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Aims Epinephrine is unique among biogenic catecholamines as a potent agonist of β 2 -adrenoceptors. The β 2 -adrenoceptor mediated effects during development might be linked to the increase of epinephrine synthesis. Our purpose was to characterize β-adrenoceptor-mediated relaxation in the aorta of newborn and young rabbits (3 to 4 months old), and to relate those responses with the epinephrine content of the adrenal gland. Main methods The epinephrine levels and the tyrosine hydroxylase activity were determined in adrenal glands of newborn and young rabbits. Also, concentration–response curves to phenylephrine (selective α 1 -adrenoceptor agonist), dobutamine (selective β 1 -adrenoceptor agonist), terbutaline (selective β 2 -adrenoceptor agonist), and CL 316243 (selective β 3 -adrenoceptor agonist) were determined in isolated aortic rings obtained from both groups. Key findings The adrenal gland content and the plasma concentrations of epinephrine were lower in newborn than in young rabbits. In contrast, the tyrosine hydroxylase activity was higher in newborn than in young rabbits. On the other hand, the maximal response to phenylephrine was lower in newborn than in young rabbits. Terbutaline at concentrations selective for β 2 -adrenoceptors had no relaxing effects in neonates, in contrast to young rabbits. The potency and the maximal response of neither dobutamine nor CL 316243 were significantly different between the two groups. Significance In rabbits, as well as in humans, β 2 -adrenoceptor-mediated responses and epinephrine synthesis are both immature at birth. On the other hand, the β 1 and β 3 -adrenoceptor-mediated responses are fully developed. We conclude that epinephrine may influence the development of the β 2 -adrenoceptor-mediated responses at birth and the rabbit is an excellent model to study these issues.

Endothelin (ET)-1(1–31) is a novel vasoconstrictor peptide produced by human mast cell chymase, which selectively cleaves big ET-1 at the Try31-Gly32 bond. We investigated the localization of ET-1(1–31) in various hamster tissues by immunohistochemistry and compared it to the distribution of ET-1(1–21). We found that the localization and amount of ET-1(1–31) were different from those of ET-1(1–21) in each tissue. ET-1(1–31)-like immunoreactivities (IR) in the heart, lung, and adrenal gland were observed in the same areas as ET-1(1–21) but were significantly weaker, suggesting that ET-1(1–31) might play a role only in mast cell/chymase-related pathological conditions in these tissues. In the liver, ET-1(1–31)-like IR was strongly detected in Kupffer cells where ET-1(1–21)-like IR was seen more weakly. In the kidney, ET-1(1–31)-like IR was slightly higher than ET-1(1–21). These results suggest that ET-1(1–31) might have physiological roles distinct from those of ET-1(1–21) in some hamster tissues.

The phytochemical flavonoid genistein has been shown to act as a potent competitive inhibitor of human adrenocortical 3beta-hydroxysteroid dehydrogenase and cytochrome P450 21-hydroxylase activities in vitro [J. Steroid Biochem. Molec. Biol. 2002; 80: 355-363]. In the present study, we evaluated the effects of large amounts of genistein continuously administered to weanling rats, particularly on steroidogenesis at the pubertal stage in vivo. Serum concentrations of free and total genistein were significantly higher in the 40 mg/kg genistein administration group when compared with the control group. In genistein administered rats, adrenal weight was significantly higher. Furthermore, a clear expansion of cells was observed in hematoxylin and eosin stained tissue at the zona fasciculata and zona reticularis of the adrenal cortex. However in the testis, no differences in weights or histologic changes were observed. Serum corticosterone concentration significantly decreased to 50% of control levels by 40 mg/kg genistein administration and testosterone also tended to decrease with this dose of genistein. On the other hand, although serum follicle stimulating hormone was unchanged, adrenocorticotropic hormone and luteinizing hormone levels increased with genistein administration. These results suggest a significant effect of genistein on steroidogenesis in the adrenal gland and testis of rats, and this effect appeared to be more evident on steroid production in adrenals than in testis in vivo.

Dehydroepiandrosterone (DHEA), a major steroid secreted by the adrenal gland, is known to have antiproliferative effects but the mechanism is unclear. We recently reported that DHEA induces growth inhibition and apoptosis in BV-2 cells and these effects are inversely associated with glucose concentrations in the medium. Here, we further showed that incubation of BV-2 cells with DHEA under glucose deprivation (G0) led to dose- and time-dependent decrease in cellular ATP levels. The decrease in ATP preceded growth inhibition and apoptosis induced by DHEA and all these effects of DHEA (i.e., loss of ATP, antiproliferation and apoptosis) were prevented by glucose added at 4.5 mg/ml (G4.5) during incubation. In addition, two ATP-depleting agents, iodoacetic acid (IAA) and 2,4-dinitrophenylhydrazine (2,4-DNP), potentiated the antiproliferative and apoptotic effects of DHEA. We also determined whether decrease in nucleic acid synthesis (due to glucose-6-phosphate dehydrogenase inhibition by DHEA) contributes to DHEA-induced antiproliferation and apoptosis. Using a mixture of deoxyribonucleotides (DN) and ribonucleotides (RN), we showed that DNRN had little or no effect on DHEA-induced growth inhibition and apoptosis. We also showed that mevalonic acid (MVA) did not affect DHEA-induced antiproliferation and apoptotic effects, indicating that protein isoprenylation and membrane association are not affected by DHEA in BV-2 cells. Taken together, the present results demonstrate that depletion of ATP by DHEA plays an important role in DHEA-induced antiproliferation and apoptosis of BV-2 cells.

Leptin is a pleiotropic hormone that regulates body weight and energy expenditure. Recent findings suggest that leptin may be involved in acute and/or chronic inflammation, however only limited results are available describing the effects of in vivo models of acute inflammation on leptin secretion. The aim of this study was to evaluate serum leptin levels in response to two well-established models of acute inflammation in rats: carrageenan rat paw induced oedema and carrageenan induced pleurisy. Our results clearly show that leptin levels rise in rats in which both oedema and pleurisy were induced. Serum leptin levels in carrageenan induced paw oedema were 3.86+/-0.16 microg/L in comparison to 1.83+/-0.17 microg/L of control animals (p0.001). A similar result was observed in carrageenan induced pleurisy animals in which leptin levels were 4.87+/-0.27 microg/L in comparison to 2.19+/-0.16 microg/L of control animals (p0.001). The increase in leptin levels induced following carrageenan-induced pleurisy appears to be dependent on adrenal function and it is markedly blunted in adrenalectomized rats. Leptin levels in carrageenan induced pleurisy, carried out on adrenalectomized rats, were lower than intact inflamed animals, suggesting a possible involvement of endogenous glucocorticoids. In summary the results here presented show that: a) an elevated plasma leptin concentration was induced during experimental models of inflammation b) this increase is mediated to a large extent by glucocorticoids. In conclusion, acute experimental models of inflammation are associated with changes in circulating leptin suggesting a possible involvement of this hormone in the anorexia/cachexia that is frequently associated with inflammatory processes. Furthermore, our data indicate the existence of a feedback loop among glucocorticoids and leptin which might contribute to the immune response to lace the inflammatory process.

Dehydroepiandrosterone (DHEA), a major steroid secreted by the adrenal gland which decreases with age after adolescence, is available as a over-the-counter product. This study demonstrates that DHEA induced lysis of human red blood cells (RBCs) in a concentration-dependent manner, with ca. 70% hemolysis at 2 mM DHEA at 37 degrees C for 1 hr. Hemolysis induced by 2 mM DHEA was rapid and involved neither hemoglobin oxidation nor lipid peroxidation. The hemolysis was also not inhibited by addition of EDTA, catalase, superoxide dismutase, glucose or a radical scavenger including mannitol, dimethylsulfoxide and alpha-tocopherol, indicating a non-oxidative mechanism. RBCs stored overnight before incubation with DHEA were hemolyzed to a lesser extent than the freshly prepared RBCs. Light microscopy of the fresh RBCs following 1-h incubation with 2 mM DHEA revealed thickened and cup-shaped deformity of the membranes, suggesting a change in the membrane structure possibly due to the intercalation of the steroid into the membranes.

Aims: The purpose of the current study was to evaluate the significance of the endothelin system in catecholamine release and synthesis in the adrenal gland. Main Methods: Primary cultures of isolated bovine adrenal medullary cells were prepared. Gene expression, intracellular calcium changes, epinephrine release, and other factors were investigated. Key findings: Expression of endothelin receptors in the rat adrenal gland was confirmed. Intravenous infusion of endothelin-1 (1.0 nmol) increased blood pressure (systolic and diastolic). Endothelin-1 stimulated intracellular calcium changes, resulting in increased nuclear factor of T cell (NFAT) activity and epinephrine release from cultured adrenal medullary cells. Furthermore, endothelin-1 increased catecholamine synthesis and caused hypertrophic changes in the cell size. Significance: Our findings indicate involvement of the endothelin system in the sympathetic regulation of the adrenal medulla., 弘前医学. 65(2-4), 2014, p.218-226

That serotonin (5HT) is involved in regulating hypothalamic-pituitary- adrenal axis (HPA) function has long been recognized. A variety of drugs including precursors of 5HT such as 5HTP, drugs which release 5HT such as fenfluramine and drugs which act directly on 5HT receptors such as ipsapirone increase cortisol and ACTH concentrations. There is a general assumption that such stimulation occurs at a hypothalamic level. However, our increasing understanding of the complex interplay between 5HT and the HPA raises questions as to the validity of this simple model. An increasing volume of experimental research indicates that 5HT can act directly on the adrenal gland and possibly on the anterior pituitary as well. These findings have major implications for the interpretation of neuroendocrine studies of 5HT conducted in psychiatric conditions, such as depression.

The mechanism of the hyperglycemic response to intraperitoneally administered serotonin (5-HT) was studied in rats. 5-HT i.p.-induced hyperglycemia was strongly antagonized by the 5-HT2A receptor antagonist ketanserin. 5-HT did not affect the serum insulin levels and increased plasma glucagon levels only at the high dose of 10 mg/kg. 5-HT dose-dependently induced a remarkable increase in plasma adrenaline levels and these effects were antagonized by ketanserin. 5-HT-induced hyperglycemia was abolished by adrenodemedullation. These results suggest that the hyperglycemic effects of 5-HT are closely related to the release of adrenaline from the adrenal gland, mediated by 5-HT2A receptors.

Adrenomedullin, a novel hypotensive peptide, was discovered in human pheochromocytoma. Although adrenomedullin exists also in normal adrenal medulla and several other organs, its effect on steroidogenesis in adrenal cortex has not been studied. We examined the effect of adrenomedullin on aldosterone secretion by the dispersed rat adrenal zona glomerulosa cells. Adrenomedullin (10(-12)-10(-7) M) did not affect basal aldosterone secretion. Adrenomedullin dose dependently inhibited aldosterone secretion stimulated by 10(-9) M angiotensin II and 10 mM potassium, whereas 10(-9) M ACTH-stimulated aldosterone was not significantly inhibited by adrenomedullin. N6,O2'-dibutyryladenosine 3':5'-cyclic monophosphate (db-cAMP, 10(-5)-10(-3) M) and Ca+ ionophore A23187 (10(-8)-10(-6) M) stimulated aldosterone secretion dose dependently, and A23187-stimulated secretion was significantly inhibited by adrenomedullin (10(-8) M), but db-cAMP-stimulated secretion was not inhibited by adrenomedullin. Our data suggest the possibility that adrenomedullin is a novel inhibitory peptide of aldosterone secretion induced by increasing concentration of intracellular free calcium.

Male Sprague-Dawley rats (130-150 g) with bilateral adrenal enucleation were used in this study. Animals were sacrificed at 2, 7, and 11 days post enucleation and plasma corticosterone and adrenal gland acetylcholine-esterase (AChE), choline acetyltransferase (ChAT), corticosterone, epinephrine (EP) and norepinephrine (NE) were assayed. The results show a progressive and gradual increase in plasma and adrenal corticosterone levels, AChE, ChAT, EP, and NE levels in the regenerating adrenal cortex from day 2 to day 11 post bilateral adrenal enucleation. At day 11 post surgery, the activities of ChAT and AChE were 60% and 25%, respectively when compared to sham operated control. The EP and NE levels returned to normal levels after 11 days post surgery in the regenerating gland when compared to the sham control. The presence of both cholinergic enzymes and the availability of high levels of catecholamine strongly suggest a progressive development of sympathetic innervation in the regenerating adrenal cortex.

Aims To investigate the signaling of prolactin (PRL) in the adrenal gland during stress in Hatano high- (HAA) and low-avoidance (LAA) rats. Main methods Adrenal glands of both strains were collected at 0, 15 and 30 min after stress. The protein levels of phosphorylated STAT5 and the mRNA levels of melanocortin receptor 2 (MC2R) and PRL receptor (PRLR) were analyzed. Furthermore, the effects of bromocriptine-induced hypoprolactinemia on adrenocortical responses to stress were investigated. Key findings Adrenocorticotropic hormone (ACTH) concentrations in HAA were greater than LAA, while the difference in PRL concentrations were found only at 120 min after stress induction. No strain differences were observed in corticosterone or progesterone in response to stress. The stress-induced increase in MC2R mRNA expression was higher in HAA, but there was a lowered PRLR mRNA expression. STAT5 become highly phosphorylated in response to stress in both strains, but bromocriptine led to a reduction the STAT5 phosphorylation. Exposure to bromocriptine was associated with a reduction in plasma PRL in response to stress in both strains, while the ACTH levels were not altered. However, the decrease in corticosterone and progesterone in response to stress was observed only in bromocriptine-treated LAA rats. Significance These data show that PRL plays an important role in the regulation of corticosterone and progesterone release in LAA but not in HAA during stress. These results suggest that PRL increase in response to stress, and it acts on the adrenal cortex and thereby plays an important physiologic role in protecting against acute stress.

This work analyzes the 24-hour changes of hypothalamic–pituitary–adrenal (HPA) axis activity and leptin release in aged rats. Three- and 22-month-old male Wistar rats were killed at 6 time intervals during a 24- hour cycle (n= 8–10 rats/group). Aging augmented plasma ACTH while it decreased plasma and adrenal gland corticosterone levels. Plasma and adrenal corticosterone levels attained high levels during all the scotophase, concomitantly with the maxima in ACTH levels, whereas in aged rats only a brief plasma corticosterone peak at the early scotophase and no time of day variations of adrenal corticosterone were observed. Aging augmented circulating leptin, with a significant interaction “age × time” in the factorial ANOVA, i.e. only in young rats time of day changes were significant, with the lowest values of leptin at the middle of the light period and higher values at night. When plasma leptin was expressed on body weight basis, the age-related differences became not significant but the daily pattern of plasma leptin found in young rats persisted. Plasma and adrenal corticosterone levels correlated significantly with plasma ACTH only in young rats. Likewise, plasma leptin correlated with plasma corticosterone only in young rats. These changes can be attributed to a disrupting effect of aging on the homeostatic mechanisms modulating HPA activity and leptin release. Fil: Cano, Pilar. Universidad Complutense de Madrid; España Fil: Cardinali, Daniel Pedro. Universidad Complutense de Madrid. Facultad de Medicina. Departamento de Fisiología; España. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Spinedi, Eduardo Julio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina Fil: Esquifino, Ana I.. Universidad Complutense de Madrid; España

Chronic voluntary running of mice is known to increase the circadian peak of plasma corticosterone without change in the level of adrenocorticotropic hormone (ACTH). In order to investigate how chronic exercise modulates the circadian HPA axis, we used two weeks of voluntary wheel running of mice and confirmed the significant increase of the circadian peak of plasma corticosterone without alteration in ACTH level. To elucidate the mechanisms of exercise modulation on corticosterone synthesis, we first examined the levels of transcripts involved in corticosterone synthesis of the adrenal gland. Among them, only steroidogenic acute regulatory protein (StAR), the rate-limiting factor that transfers substrate cholesterol into inner mitochondrial membrane, showed significantly higher expression in the exercise group. Since the splanchnic nerve input to the adrenal gland has been reported as a factor involved in the direct modulation of corticosterone synthesis, we next examined the expression levels of enzymes for the catecholamine synthesis as indices of sympatho-adrenomedullary activity. We found that the only rate-limiting enzyme, tyrosine hydroxylase (TH), was significantly higher in the adrenals of exercise group. In addition to the increment of StAR and TH mRNA in response to the chronic exercise, surprisingly, we found only these factors showed the circadian variation in its expression levels that was correlated to the circadian rhythm of corticosterone. Chronic exercise seems to alter the circadian corticosterone synthesis, at least partially via altering the levels of circadian-regulated transcripts, StAR and TH of the adrenal gland.

Although serotonin, serotonin uptake inhibitors and serotonin precursors (including tryptophan or 5-hydroxytryptophan) are known to have hypoglycemic action in rodents or human, it is not clear whether serotonin has hypoglycemic effect in streptozotocin-induced diabetic rats (STZ-diabetic rats). The aim of this study was to investigate the action of serotonin in regulating the plasma glucose STZ-diabetic rats. Plasma glucose, insulin, beta-endorphin and adrenaline were assessed after intraperitoneal administration of serotonin. Serotonin produced hypoglycemic effects without altering plasma insulin and adrenaline levels but increasing beta-endorphin level in STZ-diabetic rats. The glycogen content in soleus muscle was increased at 90 min after application of serotonin (0.3 mg/kg) in STZ-diabetic rats. Dihydroergotamine (non-selective 5-HT receptor blocker) and pimozide (5-HT(7) receptor blocker) abolished the hypoglycemic effect of serotonin in STZ-diabetic rats. Serotonin-induced hypoglycemic effect in association with the increase of beta-endorphin release was abolished in bilaterally adrenalectomized STZ-diabetic rats. In isolated adrenal gland of STZ-diabetic rats, the increase of beta-endorphin secretion in response to serotonin was reduced by either dihydroergotamine or pimozide. Pretreatment with naloxone (1.0 mg/kg, i.p.) prevented serotonin-induced plasma glucose lowering effect in STZ-diabetic rats. The results demonstrated that serotonin may activate 5-HT(7) receptor on rat adrenal gland to enhance of beta-endorphin secretion, which then stimulates the opioid receptor to increase peripheral glucose utilization, resulting in decreased plasma glucose levels in STZ-diabetic rats.

Exercise has been recommended as a remedy against a worldwide obesity epidemic; however, the onset of excessive weight gain is not fully understood, nor are the effects of exercise on body weight control. Activity deficits of the sympathetic nervous system, including the sympathoadrenal axis, have been suggested to contribute to high fat accumulation in obesity. In the present work, swim training was used to observe fat accumulation and adrenal catecholamine stocks in hypothalamic-obese mice produced by neonatal treatment with monosodium L-glutamate (MSG). MSG-treated and normal mice swam for 15 min/day, 3 days a week, from weaning up to 90 days old (EXE 21-90); from weaning up to 50 days old (EXE 21-50) and from 60 up to 90 days old (EXE 60-90). Sedentary MSG and normal mice (SED groups) did not exercise at all. Animals were sacrificed at 90 days of age. MSG treatment induced obesity, demonstrated by a 43.08% increase in epididymal fat pad weight; these adult obese mice presented 27.7% less catecholamine stocks in their adrenal glands than untreated mice (p

Multidrug resistance-associated proteins (Mrps) are ATP-dependent transporters which transport a wide variety of anionic and cationic compounds. The purpose of this study was to determine the tissue distribution of Mrp5 and 6 in male and female Sprague-Dawley rats in various tissues, and to investigate whether the expression is altered by cholestasis or administration of microsomal enzyme inducers (MEIs). These MEIs activate six different transcriptionally-mediated pathways, and their effects on Mrp5 and Mrp6 expression were determined. The effects of bile-duct ligation, a cholestasis model, on Mrp5 and 6 expression in male rats were quantified. Mrp5 had marked expression in adrenal gland, and moderate expression in cerebral cortex, cerebellum, and stomach. The MEIs polychlorinated biphenyl (PCB)126, phenobarbital, and PCB99 slightly repressed Mrp5, but no single class of receptor agonists induced or repressed Mrp5. Bile-duct ligation tended to increase Mrp5 expression, but was not statistically significant at a 3 day timepoint. Mrp6 expression was highest in intestine, liver, and kidney. Mrp6 was slightly repressed by phenobarbital, dexamethasone, and isoniazid, but no one class of receptor agonists induced or repressed Mrp6, and expression was also unchanged bile-duct ligation. In conclusion, Mrp5 in rats is most highly expressed in the adrenal gland, whereas Mrp6 is mainly expressed in excretory organs (liver, intestine, and kidney), suggesting markedly different functions. Hepatic mRNA levels of Mrp5 or Mrp6 do not seem to be coordinately regulated along with Phase I enzymes via receptor-mediated pathways, and are not part of the hepatoprotective upregulation of basolateral transporters that occurs during cholestasis.

Rats were exposed to toluene (1,500 ppm for 4 hr per day) for 7 days. The body weight of the rats was significantly lower and the weight of the adrenal gland was significantly higher in the toluene inhalation group compared to the controls. Microscopically, there was no obvious change in the medulla, but hypertrophy of the cortex was observed in the toluene inhalation group. And, the size of adrenocortical cells in treated-rats was also significantly enlarged than the control. Immunohistochemical staining did not show a clear difference in localization of aldosterone-positive cells between the control and inhalation groups. Expansion of the corticosterone-positive area consistent with the cortical hypertrophy was recognized in the inhalation group. Enhancement of 72 kD-heat-shock protein (HSP70)-expression in the toluene inhalation group was not observed. Neither stress nor damage to cortical cells due directly to toluene exposure was observed in the cortex. Also, there was no obvious difference in the anti-proliferating cell nucleus antigen (PCNA)-immunostaining between control and inhalation groups. Thus, it is suspected that cortical hypertrophy was the result of cell enlargement due to the stimulation of the cortical cells. Corticotropin-releasing factor (CRF) immunoreactivity in the paraventricular nucleus (PVN) was increased in the inhalation group. Concentration of plasma ACTH was elevated significantly by toluene exposure. The amounts of mRNA of adrenocortical steroid metabolism gene, cytochrome side-chain cleavage (P450scc), was also increased by toluene inhalation. Toluene exposure might induce adrenocortical hypertrophy via the hypothalamus-pituitary-adrenal gland (HPA) axis.

To determine if the chemotherapeutic drug cyclophosphamide influences the activity of the sympathetic nervous system, the effects of cyclophosphamide on norepinephrine concentration in the heart, adrenal gland, spleen, and thymus gland were evaluated. Male BALB/cByJ mice were administered a single injection of cyclophosphamide (15, 50, or 100 mg/kg, i.p) or saline-vehicle. Organs were collected 72 or 120 h after injection and norepinephrine concentrations were determined by high pressure liquid chromatography with electrochemical detection. Cyclophosphamide reduced spleen, thymus gland, and heart mass while also elevating spleen and thymus gland norepinephrine concentrations (both pmoles/mg tissue and pmoles/mg protein) in a dose- and time-dependent manner. Norepinephrine concentrations in heart and adrenal gland were not altered by cyclophosphamide at any drug dose or time point. Dose- and time-dependent cyclophosphamide-mediated changes in peripheral norepinephrine levels in the spleen and thymus gland are interesting because subjects administered cyclophosphamide may be more susceptible to opportunistic infections, not only because the drug is antineoplastic, but also because the drug alters nervous system-immune system communication and the neurochemical milieu in which surviving cells interact.

Chemical sympathectomy with guanethidine (Gnt) selectively destroys the postganglionic noradrenergic neurons, whereas dopaminergic fibers and nonneural catecholamine-secreting cells are spared. As a result, the relative proportions of norepinephrine (NE), epinephrine (E), and dopamine (DA) in tissues can be differentially affected. This study was done to show the possible differences in the relative amount of catecholamines in some organs and tissues that might indicate the nature of the secretory cells from which they originate. The contents of NE, E, and DA were assessed in rats neonatally treated with Gnt. Gnt-treated rats showed significantly lower levels of NE (P < 0.01) in all tissues except the adrenal gland and paraganglia. Epinephrine was present in all tissues with mean levels below 25 ng/g, with the exception of the adrenal gland (700 microg/gland) and paraganglia (100 ng/g). Only the heart showed lower values in Gnt-treated rats. Mean DA levels were also very high in paraganglia (530 ng/g). In the Gnt-treated rats, DA levels fell practically to zero except in the duodenum, mesentery, and adrenal, whereas there were high levels in the paraganglia, which were significantly different from controls. The results suggest that the three catecholamines are contained mainly in noradrenergic sympathetic fibers of muscle, white adipose tissue, heart, liver, pancreas, and spleen. The duodenum and mesentery may have dopaminergic fibers or E- and DA-containing nonneural cells. Hepatic-vagus paraganglia contain all the catecholamines in relatively high amounts in nonneural cells, and Gnt treatment raises DA levels without affecting the other amines.

High doses of diazepam (10–20 mg/kg) were shown to reduce the volume of acute carrageenan-induced inflammatory paw edema in rats. This effect was not observed after adrenalectomy or long-term use of similar doses of diazepam. The present experiment was undertaken to analyze the effects of long-term (21 daily injections) treatment with diazepam (10 mg/kg) on both carrageenan-induced paw edema (CIPE) and corticosterone serum levels. For comparison, the effects of a single and acute 10 mg/kg dose of diazepam were also analyzed. Results showed that: 1- long-term diazepam treatment induced no changes in CIPE values and corticosterone serum levels; 2- acute diazepam treatment reduced CIPE values and increased corticosterone serum levels; 3- the plasmatic levels of diazepam measured 1 hour after the single treatment or 1 hour after the last dose of long-term diazepam administration were not different. These results indicate the development of tolerance to diazepam effects on both CIPE and corticosterone serum levels and suggest a relevant role for corticosterone on diazepam-induced inhibition of acute inflammation. Data were discussed in the light of peripheral benzodiazepine receptor site (PBR) activation within adrenal gland cells by diazepam, thereby increasing the serum levels of corticosterone and thus reducing CIPE. Possible actions of diazepam on HPA axis activity and/or on cytokine network were also discussed.

Selective REM sleep deprivation was carried out under the conditions designed to minimize the adverse influence of environmental conditions and restricted movement, and the influence of REM sleep deprivation on adrenocortical steroid metabolism was investigated by measuring the steady-state levels of mRNAs encoding steroid metabolism-related genes, steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme cytochrome P450 (P450scc) and steroid 5alpha-reductase (5alpha-R), in rat adrenal glands. Selective REM sleep deprivation caused a significant decrease in StAR mRNA and an increase in 5alpha-R mRNA levels without any notable change in P450scc mRNA levels in the adrenal gland. In contrast, non-selective sleep disturbance, resulting in the partial reductions of non-REM and REM sleep, tended to increase both StAR and P450scc mRNA levels without any statistical significance. These results indicate that REM sleep deprivation by itself may affect the expression of steroid metabolism-related genes in the adrenal gland, suggesting a possible relation between REM sleep and adrenocortical steroid metabolism.

Stress proteins (heat shock proteins, HSP) play essential roles in folding, assembly and translocation of polypeptides and also in maintenance of the integrity of polypeptides as molecular chaperones. Since long-lasting hyperglycemia causes modification of cellular proteins, it is possible that expression of molecular chaperones may be altered during the course of diabetes. Here, we examined the cellular levels of stress proteins such as HSP105, HSP90 and HSC70/HSP70 in various tissues of streptozotocin-induced diabetic rats. In comparison to controls, the levels of HSC70 were markedly decreased in the liver but not in the brain, adrenal gland and pancreas of diabetic rats. The levels of HSP105 and HSP90 were not significantly changed in these tissues of diabetic rats. Furthermore, the induction of HSP70 as well as HSC70 by hyperthermia was significantly reduced in the liver and adrenal gland of diabetic rats. These results suggested that the expression and induction of HSC70/HSP70 may be altered during the course of diabetic disease and may result in impairment of the cytoprotective ability of diabetic rats.

Tissue distribution of bikunin mRNA, which encodes a Kunitz-type serine protease inhibitor of the inter-alpha-inhibitor family (IalphaI), was studied in rats and mice by the reverse-transcripsion polymerase chain reaction (RT-PCR). We found that the liver as well as other tissues, such as the kidney, testis and adrenal gland, expressed bikunin mRNA. Although signals of bikunin mRNA were faint in the whole brain of rats and mice, distinct signals were found in limited portions of rat brain, such as the hippocampus, cerebral cortex and pituitary, but undetectable in cerebellum, medulla oblongata, hypothalamus, striatum, midbrain and choroid plexus. In three distinct types of cells, such as neurons, astrocytes and meningeal cells, in primary cultures isolated from the cerebral cortex and meninges of 1-day-old newborn rats, only neurons positively expressed bikunin mRNA. These results suggest that, in addition to peripheral tissues, neurons in the hippocampus and cerebral cortex produce bikunin, suggesting a potential role of bikunin/IalphaI family in these brain regions.

Endothelins (Et-s) are biologically active peptides which play a physiological and pathological role in the cardiovascular regulation. The aim of our study was to verify, in a model of experimental long term myocardial ischemia (15 weeks) in rats, whether there was a modification in the ET binding sites of aorta and adrenal glands. Additionally, Ang II binding sites in adrenal glands were studied. The principal finding of the present study was the down-regulation of ET binding sites in adrenal glands of chronic infarcted rats, whereas no modification of binding parameters for Et-1, in thoracic aorta, nor for Ang II, in adrenal glands, were found.

To clarify functional compensation between the sympathetic nerves and the adrenal medulla, the effects of adrenodemedullation and chemical sympathectomy on norepinephrine (NE) turnover in some sympathetically innervated tissues and on NE and epinephrine (E) turnover in the adrenal gland were studied in rats. The rate of NE turnover was significantly accelerated by bilateral adrenodemedullation in the pancreas and in interscapular brown adipose tissue (IBAT). Chemical sympathectomy accelerated E turnover in the adrenal gland. These data indicate that some adrenergic nerves show functional compensation under conditions of depression of the adrenal medulla, and that compensatory acceleration of the adrenal medullary function occurs under conditions of adrenergic dysfunction.

Summary In separate experiments, nine (n-20) and fifteen (n-12) month old rats were treated with either 6% ethanol or 12% sucrose (to balance caloric intake) in the drinking water to examine the effect of chronic ethanol consumption on the hypothalamic-pituitary-adrenal axis of aged rats. Rats were maintained on these treatment regimens for thirty days and were killed by decapitation. Blood was collected and plasma concentrations of adrenocorticotropin (ACTH) and corticosterone were determined by radioimmunoassay. Adrenal glands were cleaned, quartered and used to test in vitro responsiveness to ACTH. Anterior pituitary glands from all 15 month old rats and one half of the nine month old rats were collected, frozen and extracted for measurement of tissue ACTH concentration. The remaining anterior pituitary glands from the nine month old rats were challenged with corticotropin releasing hormone (CRH) to test in vitro responsiveness. In nine month old rats, chronic ethanol consumption decreased plasma ACTH and corticosterone (P,0.05). Pituitary ACTH concentrations were unchanged in treated nine month old rats, but the amount of pituitary ACTH released in response to CRH was decreased (P,0.05) in rats consuming ethanol. In vitro responsiveness of the adrenal gland to ACTH in nine month old rats consuming ethanol was unchanged (P,0.05). Plasma ACTH and corticosterone concentrations were also decreased in 15 month old rats chronically consuming ethanol (P~0.05). No differences were noted in responsiveness of the adrenal gland or in the amount of pituitary ACTH due to ethanol consumption in 15 month old rats (!)>0.05). The results of these experiments indicate that chronic ethanol consumption decreases hypothalamic-pituitary-adrenal function in aged rats. Alcohol abuse and dependence are serious health problems that affect approximately 10% of the adult population in the United States and contribute to at least 3% of all deaths annually (1). A recent report indicated that a history of heavy alcohol consumption was a predictor of impaired physical, psychological and social health, as well as social functioning in elderly men (2). Studies examining the effect of chronic ethanol consumption in laboratory animals have largely been limited to mature animals but have not examined the effect of chronic ethanol consumption in the aged (9 to 15 month) rat. For example, the following studies have been conducted in rats of 3 to 6 months of age. Chronic exposure to ethanol has been shown to result in elevated concentrations of ACTH due to increased CRH secretion (3) and to increase sensitivity of the anterior pituitary gland to CRH (4,5). Other researchers have shown depressed hypothalamic-pituitary-adrenal (HPA) function in response to chronic ethanol consumption. Dave and coworkers (6) found that long term consumption of ethanol decreased pituitary CRH receptor number, pituitary adenyl cyclase activity and anterior pituitary proopiomelanocortin levels. Rivier et ai. (7) recently reported that basal ACTH and corticosterone

Adrenal quarters from adult male or female hamsters were incubated in the presence of melatonin (10−7 or 10−4 M), and cortisol concentration in the incubation medium was assayed by RIA. Melatonin did not change cortisol output by adrenals obtained from the male hamsters, while a slight stimulatory effect was observed in female glands, the lower concentration of melatonin being more effective than the higher one. At both concentrations tested, melatonin notably stimulated corticosterone output by isolated rat adrenocortical cells derived from the males, and lowered corticosterone secretion by the cells obtained from the female glands only at a concentration of 10−7 M. The lower concentration of melatonin increased ACTH (0.1 mU. m1−1) -stimulated corticosterone output by the cells of male and female rat adrenals. The pineal hormone was ineffective at a concentration of 10−4 M, as well as in the presence of a higher dose of ACTH (1.0 mU.m1−1). These findings indicate a distinct sex-dependent effect of melatonin on in vitro cortisol and corticosterone production, and demonstrate that the modulatory effect of melatonin of the secretion of steroid hormones is more effective at lower concentrations.

By use of a mass fragmentographic technique the distribution of piperidine in tissues and changes in levels under physiological conditions were examined. Only trace amounts of piperidine existed in the brain of several animal species, although higher concentrations were detected in other species. In the brain of rats and rabbits, some regional differences were seen and high concentrations were found in the striatum. Piperidine levels in the brain and adrenal gland similarly showed the daily and seasonal rhythmic fluctuations.

Levels of GTP cyclohydrolase, neopterin and biopterin were determined in tissues and body fluids of humans, monkey, dog and mouse. Highest levels of GTP cyclohydrolase and biopterin were found in pineal, liver, spleen, bone marrow, whole adrenal gland and small intestine. High levels of biopterin were found in the urine of all species examined. High levels of neopterin were found only in the urine of humans and monkeys, very low levels could be detected in dog, while none could be detected in mouse, rat, guinea pig or hamster urine.

The response of adrenomedullary catecholamine synthesizing enzymes to repeated immobilization was studied in hybrid (F 1 ) offspring of 2 inbred rat strains (LEW and F344). Immobilization-induced increases in tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine-N-methyl-transferase (PNMT) activities in one of the parental strains (F344) previously were shown to be dependent upon intact adrenal gland innervation but independent of the pituitary gland, while responses in the other parental strain (LEW) were independent of adrenal innervation but dependent upon pituitary function. Factors determining immobilization-induced increases in adrenal enzymes of F 1 offspring were enzyme-specific. Increased PNMT activity was pituitary dependent in F 1 rats, whereas increased TH and DBH activities after immobilization were dependent upon an intact adrenal gland innervation. These results suggest that the factor(s) regulating PNMT responses are differentiable from those regulating TH and DBH responses. The results also indicate that analysis of PNMT responses to immobilization in backcross populations is feasible, and could indicate whether strain-specific response mechanisms are heritable.

Recent studies have shown that biologically active peptides and monoaminergic neurotransmitters coexist in certain neuronal cell populations. Using the immunofluorescence technique, we have examined the localization of enkephalins, vasoactive intestinal peptide (VIP) and tyrosine hydroxylase in the adrenal gland of the frog Rana ridibunda. Most chromaffin cells which stained for tyrosine hydroxylase contained VIP-like immunoreactivity, whereas methionine- (Met-) and leucine- (Leu-) enkephalin-like immunoreactivity was detected in about 40% of the cells revealed by the anti-tyrosine hydroxylase serum. No VIP- or enkephalin-like immunoreactive nerve fibres were observed. Since in the frog, the chromaffin cells are in close contact with the adrenocortical (interrenal) tissue, a possible action of VIP and opiates on corticosteroidogenesis has been investigated. At doses 10(-6) and 10(-5) M, 20-min infusions of synthetic porcine or chicken VIP elicited a significant increase in corticosterone and aldosterone production by perifused frog adrenals, in a dose-dependent manner. As compared to ACTH, VIP was several orders of magnitude less effective in stimulating corticosteroid production. Morphine, Met- and Leu-enkephalins (10(-5) M) had no effect on spontaneous secretion of corticosteroids. In addition, Met- and Leu-enkephalins (10(-5) M) did not alter the production of corticosterone induced by ACTH. THese results suggest that VIP contained in the chromaffin cells of the frog adrenal gland may exert a local action in stimulating corticosteroid production by the interrenal tissue.

We report the first demonstration of an Aldosterone Secretion Inhibitory Factor (ASIF) in acid extracts of bovine adrenal medulla. Following separation from catecholamines and enkephalins, this factor leads to an 80% inhibition of PGE1-stimulated secretion of aldosterone from bovine adrenal zona glomerulosa. ASIF is retained on cation exchange gels and behaves as a small 5K-dalton peptide on Sephadex G-50. This factor cross-reacts in a radio-receptor assay for [125I] atrial natriuretic factor (ANF). ASIF is distinct from all neuropeptides formerly detected in the adrenal medulla, e.g. somatostatin, enkephalin, neuropeptide Y, dynorphin, neurotensin. In the adrenal gland, this ANF-like factor is predominantly found in the medulla (4 pmo1/mg protein), with only trace amounts in the cortex (0.1 pmo1/mg protein). ASIF might perhaps correspond to the endogenous ligand for the receptor sites that we have previously identified with [125I]ANF in bovine adrenal cortex and could contribute to the formerly reported attenuating influence of the adrenal medulla on mineralocorticoid production.

Newly synthesized tyrosine hydroxylase ( TH ) induced by reserpine was compared with the enzyme in control rats in terms of the molecular and physiological properties. When repeated doses of reserpine were given at daily intervals for three days, the enzyme activity measured in homogenates of the adrenal glands was increased 3-fold. Furthermore, when TH in the adrenal glands from both control and reserpine-treated rats was purified, both total activity of the enzyme and the enzyme protein content purified from reserpine-treated rats were also about 3-fold higher than those of the control rats. The two purified enzymes revealed similar properties; a single subunit with a Mr of 60,000 was observed by SDS polyacrylamide gel electrophoresis, and the Km value for a pterin cofactor, 6-methyl-tetrahydropterin was about 300 μM. In contrast, in situ TH activity measured under physiological conditions at pH 7.2 in adrenal tissue slices was elevated 6-fold by reserpine pretreatment for 3 days, and was stimulated by carbachol (0.1 mM) and elevated K+(52 mM) in a roughly proportional rather than additive way relative to slices from untreated rats. These results indicate that newly synthesized TH induced by reserpine in rat adrenal gland had similar properties as the enzyme in control rats and that reserpine increased not only the amount of TH molecules but also the in situ activity of TH. Since reserpine also increases the biosynthesis of tetrahydrobiopterin as demonstrated by Viveros and co-workers, this 6-fold increase in in situ TH activity may depend both upon the 3-fold increase in the amount of enzyme molecules and upon the increase of the physiologically available tetrahydrobiopterin in the adrenal gland.

Lithium ions accumulated consistently in the pituitary and thyroid of rats at concentrations significantly greater than in plasma. There was also a significant, although lower, accumulation of Li + in the adrenal gland. No accumulation of lithium ion was noted in the testis or in the ovary. The possible significance of these findings with regard to some of the side effects of lithium carbonate treatment is discussed.

In previous studies we have established that intracisternal (i.c.) but not peripheral (intravenous) administration of neurotensin (NT), a brain and gastrointestinal tridecapeptide, totally prevents the development of gastric lesions produced by cold-restraint stress (CRS) with food-deprived rats. In this investigation, removal of the pituitary and adrenal gland, anterior pituitary hormone secretion and gastric acid secretion were evaluated independently as potential intermediates for NT's protective effect. NT (30 micrograms) produced a significant reduction of gastric lesions incidence and severity in intact and sham-operated controls. Adrenalectomy, but not hypophysectomy totally blocked the protective effect of i.c. NT. In addition, replacement therapy with s.c. prednisone (1 mg/kg) for 5 days following adrenalectomy did not restore the protective activity of central (i.c.) NT in adrenalectomized rats. A significant reduction of serum levels of TSH, PRL and GH following i.c. NT (30 micrograms) was observed after 2h of CRS. The gastrosecretory studies revealed that i.c. NT (30 micrograms) did not affect gastric acid secretion in pylorus ligated rats. However, blockade of peripheral (gut) cholinergic (muscarinic) receptors with i.p. atropine methylbromide (1 mg/kg) significantly raised gastric pH and reduced gastric acid concentration and output. In conclusion, the results of this study indicate that the acute protective effect of brain NT appears to be mediated, at least in part, by the sympathoadrenomedullary axis, and not by the pituitary gland or substances derived from the pituitary or by inhibition of gastric acid secretion.

Intraperitoneal injection of caerulein produced a pronounced increase in plasma corticosterone levels in intact rats. Since this effect was not observed in hypophysectomized rats, it is assumed that the peptide does not affect the adrenal gland directly. Intracerebroventricular injection of caerulein was also ineffective in stimulating corticosterone secretion, and in vitro experiments for ACTH release indicated that caerulein could not affect pituitary tissue itself. The fact that the effect of caerulein disappeared after subdiaphragmatical vagotomy suggests that the action site is at a peripheral level, but not in the central nervous system.

Inbred male CDF rats were bilaterally adrenalectomized and received either two pituitaries under each kidney capsule or were sham operated. They were tested at approximately four, seven and eight weeks after surgery. Between the first and second behavioral test, the animals received corticosterone replacement therapy. In each of the three tests, grafted animals exhibited deficits in male sexual behavior as compared to sham-grafted controls. These results suggest that, at least in CDF inbred rats, the adrenal gland is not necessary for the reduction in male sex behavior resulting from chronic hyperprolactinemia.