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The effects of corticotropin-releasing hormone (CRH) and dexamethasone on proopiomelanocortin (POMC) mRNA levels in cultured pituitary adenoma cells were studied in 10 patients with Cushing's disease. As a control, POMC mRNA levels in cells from nonadenomatous tissues were examined in four patients. Human POMC mRNA in the cells was analyzed by Northern blot hybridization. Human POMC DNA probe hybridized with only a single size class of RNA (approximately 1,200 nucleotides) from the adenoma and nonadenoma cells of each patient. The size of POMC mRNA did not change through the culture or after incubation with CRH or dexamethasone. CRH increased POMC mRNA levels in these cells in a dose- and time-dependent manner. The minimum concentration of CRH required to elevate POMC mRNA levels in these cells exposed for 15 h was 0.1 nM. The minimum duration of 1 nM CRH treatment required to increase these levels was 3 h under our conditions. Inhibitory effects of 1 and 10 micrograms/dl dexamethasone on ACTH release and POMC mRNA levels in nonadenoma cells were greater than those in adenoma cells. These results suggest the following: (a) that the mRNA in cultured pituitary adenoma cells is qualitatively the same as that in vivo; (b) that responses of mRNA levels to CRH are time- and dose-dependent; and (c) that adenoma cells resist the inhibitory effect of dexamethasone on POMC mRNA levels and ACTH release.

Eighteen patients with pituitary dwarfism were treated for 1 7/12 to 6 years with human growth hormone (hGH) at a dose of 0.19–0.62 unit (U) per kg of body weight per week. The mean increment in height was 2.0 ± 0.4 and 8.8 ± 0.5 cm/year before and the first year after treatment of hGH, respectively. A significant positive correlation was observed between serum levels of somatomedin A and growth rate, especially in children with bone age below 10 and a duration of treatment of less than one year (r = 0.66, P < 0.005). Long-term treatment with hGH was accompanied by a decreasing response. However, the serum levels of somatomedin A did not decrease significantly. Therefore, decreased growth increment in these situations was not due to decreased serum levels of somatomedin A.

The mechanism by which restraint stress induces suppression of food intake and the influence of intracerebroventricular (icv) administration of somatostatin on the anorexia induced by restraint stress were examined in the rat. Ninety minutes of restraint stress reduced food intake of rats to approximately 60% that of control. Anorexia induced by 90 min restraint stress was partially reversed by icv administration of α-helical CRF (9–41), a corticotropin-releasing factor (CRF) antagonist, and completely reversed by anti-CRF γ-globulin. These results provide further evidence in support of the theory that CRF is involved in the inhibitory mechanism of food intake in restraint stress. ICV administration of somatostatin 14 and SMS 201–995, an analog of somatostatin, also reversed restraint stress-induced anorexia. It is, therefore, suggested that somatostatin may counteract the suppressive action of CRF on food intake in stress.

Maternal adrenocortical function was studied by measuring plasma cortisol and urinary free cortisol during gestation. Changes in suppressibility of pituitary-adrenocortical function were determined by dexamethasone administration. Urinary free cortisol as well as plasma cortisol increased during the course of gestation. The suppressibility by dexamethasone became less effective as pregnancy advanced. These results suggest that pregnant women have pituitary-adrenocortical hyperfunction and tissue refractoriness to glucocorticoid which increases during the course of gestation.

Specific insulin-like growth factor I (IGF-I) receptors on the Madin-Darby canine kidney (MDCK) cell line were identified and characterized. [125I]IGF-I specifically bound to the cells, but [125I]insulin bindings to the cells was minimal. Unlabeled IGF-I displaced both the IGF-I and insulin bindings with potencies that were 100 and 10 times as great as insulin. By an affinity labeling technique, IGF type I receptors were present in the MDCK cells. IGF-I stimulated DNA synthesis and cell proliferation at physiological concentrations. On the other hand, insulin had a little effect on DNA synthesis. These data suggest that IGF type I receptors as demonstrated in MDCK cells are involved in DNA synthesis and cell proliferation.

To study the effect of acute stress on CRF release and synthesis in rat hypothalamus, ACTH levels in plasma, CRF contents in the median eminence (ME), and CRF mRNA levels in the hypothalamus without ME and cerebral cortex were determined after insulin-induced hypoglycemia. Plasma ACTH levels increased at 30 and 60 min, while ME CRF content decreased at 30 and 60 min, then returned to the control level at 90 min. Hybridization with a cRNA probe revealed a single size class of CRF mRNA in the hypothalamus and cerebral cortex (approximately 1300 nucleotides), and the size of CRF mRNA in these tissues did not change during the experimental period. CRF mRNA levels in the hypothalamus increased to 130% of the control value at 30 min and reached a peak (186% of the control value) at 120 min, but these levels in the cerebral cortex did not change. These results suggest that insulin-induced hypoglycemia stimulates CRF synthesis by increasing CRF mRNA levels in the hypothalamus as well as CRF release, and that release and synthesis of CRF in the cerebral cortex are independent of those in the hypothalamus.

Human corticotropin-releasing hormone (hCRH) test was performed in 57 normal volunteers and 102 patients with hypothalamic, pituitary and adrenocortical diseases. Intravenous bolus injection of synthetic hCRH, 100 micrograms for adults or 1.5 micrograms/kg for children, increased plasma ACTH and cortisol levels in about 90% of normal subjects. In 47 patients with Cushing's disease, plasma ACTH tended to show an exaggerated response to hCRH and peak ACTH was the most frequent abnormal component among the several reaction parameters. Poor responders among normal subjects and patients with Cushing's disease had significantly higher plasma cortisol levels before CRH administration. Patients with hypothalamic hypopituitarism showed exaggerated response, whereas patients with primary pituitary lesion, isolated ACTH deficiency or adrenal Cushing's syndrome showed no ACTH response. These differences in the response of patients suggest the value of the hCRH test in their differential diagnosis.

The effect of transforming growth factor (TGF)-beta on DNA synthesis and iodine metabolism was studied in cultured porcine thyroid cells. TGF-beta dose-dependently inhibited DNA synthesis stimulated by both insulin-like growth factor I and epidermal growth factor but did not affect the number or affinity of receptors for the two growth factors, suggesting that TGF-beta inhibits postreceptor events responsible for initiation of DNA synthesis. TGF-beta was a potent inhibitor of iodine metabolism. When porcine thyroid cells were cultured with TSH for 3 days in the presence of TGF-beta, TSH-induced iodide uptake and organification were reduced at rates that were dependent on the TGF-beta concentrations. The inhibition was detectable at TGF-beta concentrations as low as 50 pg/ml, and complete suppression was seen at 1 ng/ml. Only 6 h of exposure to TGF-beta resulted in a significant inhibition of TSH-induced iodine metabolism. Treatment of thyroid cells with TGF-beta for 3 days did not reduce cAMP production stimulated by TSH. Moreover, the intracellular cAMP level of thyroid cells cultured with TSH plus TGF-beta did not differ from that of cells cultured with TSH alone. TGF-beta decreased iodide uptake stimulated by forskolin or 8-bromo-cAMP. These results strongly suggest that TGF-beta inhibits TSH-stimulated iodine metabolism, at least in part, by affecting events subsequent to cAMP production. The physiological role of TGF-beta remains to be determined, but it may be involved in the regulation of thyroid cell growth and function.

Synthetic human pancreatic GRF (hpGRF-44) was administered sc to 8 normal children with short stature and 11 patients with GH deficiency. After a dose of 100–200 μg hpGRF-44, mean plasma GH levels reached a peak at 15 min of 27.2 ± 6.4 (± se) ng/ml in normal children. However the responses were variable and peak plasma GH varied from 10.1 to 56.5 ng/ml. Eight of 11 patients with idiopathic GH deficiency did not respond to sc administration of 100–300 μg hpGRF-44. However, a plasma GH increase of more than 5 ng/ml occurred in 2 patients and to twice the basal level in 1 patient. Their GH values were 14.3, 5.2 and 3.4 ng/ml, respectively. After repetitive administration of hpGRF-44 (200 μg, twice a day) sc for 5 consecutive days, 2 of 8 patients restored their responsiveness, but the remaining patients did not show GH rise in response to both sc and iv bolus administration of hpGRF-44. Repetitive hpGRF-44 administrations for 5 days had no effect on somatomedin-C production.

One hundred and sixty-one children with idiopathic GH deficiency who received GH treatment were followed until they reached their final height. Final height was found to be influenced by gonadal function. In 108 patients who had spontaneous puberty (91 boys and 17 girls; group A), the mean final height was 151.8 +/- 6.6 (+/- SD) cm in boys and 141.7 +/- 7.4 cm in girls. In 29 patients with combined GH and gonadotropin deficiency (23 boys and 6 girls; group C), whose pubertal development was induced artificially at age 19.5 +/- 2.1 yr in the boys and 18.6 +/- 1.8 yr in the girls, the mean final height was 163.7 +/- 3.9 cm in boys and 151.0 +/- 5.1 cm in girls. The differences in final height between groups A and C were significant in both boys and girls. The shorter final height in group A was caused by the shorter pubertal duration and smaller pubertal height gain than those in normal children. In 24 patients (17 boys and 7 girls; group B) who developed early signs of puberty, gonadal suppression therapy with cyproterone acetate and/or medroxyprogesterone acetate was given. The mean SD score of the final height in these 24 patients was -2.1 +/- 0.6, significantly higher than that in group A. This beneficial effect of gonadal suppression treatment on final height was caused by increases in the duration of puberty and the pubertal height gain.

Synthetic human pancreatic GRF (hpGRF-44) was administered as an iv bolus to 139 normal children of short stature and 63 patients with GH deficiency. After a dose of 1 and 2 μg hpGRF-44/kg BW, mean plasma GH levels peaked at 15 and 30 min, respectively, with corresponding values of 32.2 ± 3.6 and 31.8 ± 2.4 (± SE) ng/ml in normal but short children. There were no differences according to sex or age in plasma GH response to hpGRF-44 between the ages of 4 and 18 years. A similar plasma GH response was observed when 2 μg hpGRF-44/kg BW was administered two hours after lunch. The overall plasma GH response was greater than that of insulininduced hypoglycemia and was similar to that obtained in the glucagonpropranolol test.Thirty-five of 63 patients with GH deficiency did not respond to a 2 μg hpGRF-44/kg BW. However, plasma GH increases to greater than 5 ng/ml occurred in the remaining 28 patients. Their mean GH level reached a peak at 90 min with a value of 8.8 ± 0.8 ng/ml. The peak values ranged between 5.1 and 17.8 ng/ml with a mean of 9.5 ± 0.8 ng/ml.These results suggest that hpGRF-44 is useful for evaluating pituitary Gil reserve in children of short stature and that some patients with GH deficiency, diagnosed on the basis of established tests, have Gil responses to hpGRF-44.

The present study was conducted to examine roles of brain monoamines and opioid peptides in growth hormone (GH) secretion in unanesthetized, freely behaving rats. The administration of chlorpromazine (CPZ, 300 microgram/100 g, i.v.), an antagonist of brain monoamines, to rats that were passively immunized with antiserum to somatostatin immediately lowered plasma GH levels and inhibited episodic GH secretion. An intraventricular injection of beta-endorphin (3.5 microgram) stimulated GH secretion. This effect was completely inhibited by the prior administration of naloxone (100 microgram/100 g, i.v.), a specific antagonist of opioid peptides, but not by CPZ. In addition, the administration of naloxone did not inhibit episodic GH secretion. The results suggest that CPZ inhibits episodic GH secretion via a factor(s) other than somatostatin. It is also inferred that brain monoamines, but not opioid peptides, play major roles in the regulation of episodic GH secretion in rats.

Daily injections of methionine-free, recombinant hGH (rhGH), 8 IU, were administered in six healthy volunteers. Non-esterified fatty acid levels increased significantly from 0.45 +/- 0.06 to 1.08 +/- 0.05 mEq/litre (mean +/- SEM) at 4 hours after the first injection of rhGH (p less than 0.001). Plasma IGF-1 levels increased significantly at 24 hours after each of the four daily injections of rhGH (basal, 0.80 +/- 0.06 units/ml; 24 hours, 1.72 +/- 0.21 units/ml; 48 hours, 3.22 +/- 0.42 units/ml; 72 hours, 3.17 +/- 0.49 units/ml; 96 hours, 3.63 +/- 0.32 units/ml; p less than 0.001). Eleven patients with hGH deficiency were treated with rhGH, 0.5 IU/kg/week for 3 months. Their heights increased by between 1.1 cm and 4.1 cm during the 3 months of treatment, which was calculated to be equivalent to 4.4-16.4 cm/year, with a mean height velocity of 8.6 +/- 1.1 cm/year. Anti-hGH antibody was observed in one patient treated with rhGH and had a titre of 10.

The effect of thyroid hormone on the serum level of somatomedin A was studied using a radioreceptor assay for somatomedin A. In 13 patients with hyperthyroidism, the mean level of somatomedin A was 0.06 +/- 0.05 U/ml, which was within the normal range. Low levels were found in 19 patients with primary hypothyroidism with a mean of 0.39 +/- 0.04 U/ml. After treating these patients with thyroxine, the serum somatomedin A levels returned to the normal range. There was a significant correlation between the somatomedin A level on one hand and T3 (r = 0.49) and T4 (r = 0.55) level on the other. The serum level of somatomedin A did not decrease for 7 days after thyroidectomy nor increase after treating hypophysectomized rats with 2 microgram of thyroxine for 14 days. However, the effect of growth hormone on serum somatomedin A was augmented 42.2% by the combined administration of the same amount of T4 for 7 days. There was a positive correlation between the serum level of somatomedin A and the percentage increase in body weight (4 = 0.73). These data suggest that thyroxine potentiates the effect of GH on synthesis and/or the secretion of somatomedin A.

Effects of growth hormone (GH) excess on immunoreactive hypothalamic GH-releasing factor (GRF) and somatostatin (SRIF) were studied in rats. Hypothalamic GRF content significantly reduced after 7-day daily treatment with 160 micrograms of rat GH or after inoculation of GH-secreting rat pituitary tumors, MtT-F4 for 9 or 13 days and GH3 for 3 months. Basal and 59 mM K+-evoked release of GRF from incubated hypothalami diminished, more than the content, by 43-51% in MtT-F4 tumor- or by 67-83% in GH3 tumor-bearing rats. In contrast, there was a small but significant increase in content or release of SRIF in rats harboring the GH3 or MtT-F4 tumor, respectively. These results indicate the existence of a negative feedback loop via hypothalamic GRF as well as SRIF in control of GH secretion.

The effects of intravenously given human growth hormone-releasing hormone (1-44) NH2 (hGRH-44) on growth hormone (GH) secretion were studied in normal men.A wide variability of intersubject GH response to hGRH-44 was observed. The peak plasma GH levels in response to 50, 100 and 200μg hGRH-44 in 7 normal men were 9.1±3.2ng/ml (Mean+SEM), 19.3±3.3ng/ml and 22.4±4.0 ng/ml, respectively. Both the mean peak values for plasma GH response to 100 and 200μg were significantly greater than that for 50μg hGRH-44 injection (p

Pituitary growth hormone (GH) responses during a 10-h iv infusion of saline or human GH-releasing factor (hGRF-44) at 500 ng/kg/h, followed by an iv bolus injection of hGRF-44 at 2 μg/kg body weight, were studied in 10 patients with GH deficiency. During saline infusion in 4 patients, small plasma GH increase were observed in 2 patients. However, during hGRF infusion in 6 patients, up to 4 or 13 pulses of GH secretion were observed. The mean integrated GH pulse area during hGRF infusion was 22.5 ± 5.2 (se) ng/ml × h, which was greater than that obtained during saline infusion. Plasma somatomedin C levels did not increase after hGRF infusion. After saline or hGRF infusion all patients responded to an iv bolus injection of the peptide. These results indicate that hGRF infusion augments GH secretion by increasing the number and amplitude of GH pulses and that the infusion does not cause pituitary somatotrophs to lose their capacity to respond to hGRF subsequently.

Specific insulin-like growth factor I (IGF-I) receptors on a human erythroleukemia cell line (K-562 cells) were identified and characterized. [125I]-IGF-I specifically bound to K-562 cells and the binding was displaced by unlabeled IGF-I in a dose dependent manner, and half maximal inhibition of the binding was observed at 7 ng/ml IGF-I. [125I]IGF-I binding to the cells was displaced by multiplication stimulating activity (MSA) and by porcine insulin, with potencies that were 10, and 100 times less than that of IGF-I, respectively. By an affinity labeling technique, IGF type I receptors were found to be present in the K-562 cells. When the cells were differentiated by hemin (40 microM), specific binding of [125I]IGF-I to the cells was decreased to 56.8 +/- 5.0% of that for undifferentiated cells. Furthermore, at physiological concentration of IGF-I stimulated thymidine incorporation into DNA and increased the number of cells. These data demonstrate that K-562 cells have specific receptors for IGF-I which may be functionally important for these cells, and that the IGF-I binding sites decrease with cell differentiation. This system might be useful in studying the interaction of IGF-I receptors.

Transforming growth factor (TGFs) are a family of peptide(s) defined by their ability to induce anchorage-independent growth of non-neoplastic indicator cells in soft agar. We found that acid-ethanol extracts of human anterior pituitary tissues were able to stimulate colony growth of normal rat kidney fibroblasts in soft agar. When subjected to gel-filtration on a column of Bio-Gel P-60 in 1 M acetic acid, the majority of TGF activity eluted in fractions corresponding to an apparent mol wt 15,000. The activity was heat- and acid-stable, but was inactivated by treatment with trypsin and dithiothreitol. Pituitary TGF-like materials did not compete with epidermal growth factor (EGF) for receptor binding and did not require EGF for colony-forming activity. Thus, human pituitary TGF was not like type α or type β TGF.

Effects of chlorpromazine (CPZ) on plasma GH and prolactin levels were observed in conscious rats provided with chronic indwelling right atrial cannulae. The administration of CPZ (200 μg/100 g b.w. iv) suppressed episodic plasma GH burst and resulted in significant elevations of plasma prolactin levels. These were also observed in rats in which two types of hypothalamic deafferentation, i.e. anterior and complete, had been carried out. The data suggest that CPZ acts within the medial basal hypothalamus and inhibits episodic plasma GH secretion. In addition, it is inferred that catecholamines are involved in the generation of episodic plasma GH burst.

Synthetic rat atrial natriuretic factor (ANF) was found to attenuate, in a dose-dependent manner, basal and corticotropin-releasing factor-induced secretion of proopiomelanocortin-derived peptides from cultured anterior and intermediate lobe cells of rat pituitary. ANF was also found to suppress basal and growth hormone-releasing factor-stimulated secretion of growth hormone from anterior lobe cells of rat pituitary. These results, together with reports of the existence of ANF-positive neurons in the hypothalamus and ANF-positive fibers in the median eminence, suggest that hypothalamic ANF is probably involved in the regulation of pituitary hormone secretion, especially that of proopiomelanocortin-derived peptides and growth hormone.

The effect of metoclopramide, a dopamine blocker, on arginine vasopressin (AVP) secretion was investigated in normal males. After a bolus injection of metoclopramide (10 mg), all subjects (n = 7) demonstrated an increase of 80.3% (from 0.71 +/- 0.12 (Mean +/- S.E.) to 1.28 +/- 0.24 pg/ml, P less than 0.005) in plasma AVP at 15 min. In controls (n = 7) plasma AVP levels did not change after saline injection (2 ml). Because plasma osmolality and blood pressure did not change, the elevation of plasma AVP levels induced by treatment with metoclopramide may be due to its central effect as a dopamine inhibitor. Although plasma AVP levels increased again at 90 and 120 min after a bolus injection of metoclopramide, accompanying falls in blood pressure (4-5%) make the interpretation concerning the contribution of dopamine to AVP secretion in a late phase uncertain. In summary, plasma AVP levels were shown to be significantly increased by a metoclopramide bolus, suggesting that AVP secretion is under tonic inhibition by dopamine.

To investigate hypothalamic-pituitary functions and the primary site of the lesion in idiopathic pituitary dwarfism, various pituitary function tests, especially the pituitary hormone responses to the hypophysiotropic hormones were studied in 23 patients with idiopathic pituitary dwarfism. A few cases showed slight responses of GH to GH stimulation tests. Gonadotropin deficiencies were most frequently noted among pituitary hormones. The basal levels and the responses of plasma LH and FSH to LH-RH test were diminished markedly in all of the cases except in 5 cases with isolated GH deficiency. Responses of LH and FSH to LH-RH improved markedly after a long term administration of LH-RH for a period of one month in 2 patients with gonadotropin deficiency. As to TSH axis, half of the cases accompanied hypothyroidism. However, the responses of TSH to TRH were normal in all of the cases regardless of the thyroid function. The basal levels and the responses of plasma cortisol and 11-deoxycortisol to the rapid metopirone test were also impaired in about half of the cases. Basal levels of plasma prolactin were normal in all of the cases and the responses of prolactin to TRH were normal in cases with normal thyroid function, but slightly delayed in cases with hypothyroidism. It is concluded from the above observations that the incidences of various pituitary hormone deficiencies were quite high in this disorder and hypophysiotropic hormone deficiencies may cause pituitary hormone deficiencies. Therefore, it is suggested that the primary site of the lesion in this disorder might be at the hypothalamus.

Although the presence of atrial natriuretic factor in the blood has been demonstrated by radioimmunoassay, its biological activity and physiological significance has not been elucidated. Using specific antiserum against atrial natriuretic factor, we investigated the effect of passive immunization in rats. A significant reduction of urine output and urinary sodium excretion lasted for about 30 min after intravenous administration of antiserum. The effects were more pronounced in rats pretreated with deoxycorticosterone acetate and saline. Plasma renin activity was increased after the administration of antiserum. No significant effects on the urinary sodium excretion was observed following injection of normal rabbit serum. The results of this study provide evidence indicating that endogenous atrial natriuretic factor plays an important role in the regulation of urinary water and sodium excretion and plasma renin activity.

IM-9 cultured human lymphocytes were treated with N-linked glycosylation inhibitors, N-linked oligosaccharide processing inhibitors, or neuraminidase to study the effect of glycosylation modification on human growth hormone binding and molecular weight of surface hGH receptor. One mg/l tunicamycin and 20 mmol/l glucosamine decreased 125I-hGH binding to the cells to 46.3 ± 2.4% (mean ± sem) and 21.9 ± 0.2% of the controls, respectively. The hGH binding was 33.0 ± 18.4% of the control value in the cells treated with monensin. The inhibition of binding was due to a decrease in the hGH receptor number without any affinity changes in these cells. Neither 1 mg/l swainsonine nor 100 mg/l castanospermine had any effect on the hGH binding. On the other hand, 125I-hGH binding to neuraminidase-treated cells was significantly enhanced with accompanying affinity changes. When 125I-hGH was cross-linked to IM-9 cells, there were no differences in the molecular weight of hGH receptor complexes (140K) between untreated cells and cells treated with tunicamycin, glucosamine, monensin, or castanospermine. However, the 128K hGH-receptor complex appeared in swainsonine-treated cells; this complex was sensitive to endoglycosidase H. These data show that the altered carbohydrate moiety changed hGH binding and the size of surface hGH receptor and suggest that glycosylation of receptor is important for the binding of hGH and for its physiological action.

The effects of Na ion and choline choride on the release of atrial natriuretic factor (ANF) and growth hormone-releasing factor (GHRF) from rat hypothalmic fragments including the organum vasculosum of the lamina terminalis (OVLT) were examined in vitro. Although the release of ANF was stimulated by Na ion, choline chloride, and glucose in concentration-dependent manners, the release was more sensitive to a change in concentration of Na ion than to those of choline chloride and glucose. On the other hand, the change in Na ion concentration did not affect the release of GHRF. It can be therefore proposed that Na ion is the first candidate controlling ANF release from the brain tissue and that ANF in the hypothalamus and/or OVLT may play some role in the regulation of the Na ion and water balance in the central nervous system.

Synthetic human pancreatic GRF (hpGRF-44) was administered as an iv bolus to 28 normal children with short stature and 27 patients with GH deficiency. After a dose of 1 or 2 micrograms hpGRF-44/kg BW, mean plasma GH levels peaked at 15 and 30 min, respectively, with corresponding values of 30.1 +/- 4.7 and 33.2 +/- 3.7 ( +/- SE) ng/ml in normal but short children. The overall plasma GH response was greater than that of other GH stimulation tests such as insulin-induced hypoglycemia, glucagon-propranolol or L-dopa administration. Plasma LH, FSH, TSH, PRL, and cortisol levels were not altered by hpGRF-44 injection. Sixteen of 27 patients with GH deficiency did not respond to a 2 micrograms/kg BW hpGRF-44. However, plasma GH increases to greater than 5 ng/ml occurred in the remaining 11 patients. Their GH levels reached peaks between 15 and 90 min, with values ranging between 5.8 and 17.8 ng/ml. Two of these responding patients were infused iv with hpGRF-44 at 2.5 micrograms/min for 90 min after receiving an iv bolus injection of 2 micrograms/kg BW. Their plasma GH levels increased and remained near peak values throughout the infusion period. However, no increase in plasma GH levels occurred after a second bolus injection of hpGRF-44 given at the end of the infusion. These results suggest that hpGRF-44 is useful for the diagnosis of GH deficiency in individuals with short stature and that some patients with GH deficiency, diagnosed on the basis of established tests, have GH responses to hpGRF-44.

The concentration of somatomedin A (SMA) in various rat tissues was determined directly by the radioreceptor assay in supernates of tissue homogenates at 100,000 x g for 60 min. The SMA concentrations in pancreas, kidney, lung, liver, spleen, testis, brain and muscle were 2.56, 2.40, 2.28, 2.16, 1.56, 1.44, 0.60 and 0.30 U/g of wet tissue, respectively. The SMA content in rat serum was 6.66 U/ml. The SMA concentration in tissues never exceeded that in serum. When the 100,000 x g pellet of liver was treated with a hypotonic solution, the SMA content in the hypotonic solution was about 35% of that in the initial supernate. This result indicates that about 30% of the SMA in liver was stored in organellae. SMA in tissues decreased with incubation at 37 degrees C, though SMA in serum did not. This decrease could be precluded by adding 0.75 mM HgCl2 to the liver homogenate. The SMA content of the liver homogenate was dependent on growth hormone in experiments both in vivo and in vitro.

To elucidate the mechanism of humoral hypercalcemia elicited by human esophageal carcinoma cells (EC-GI), which constitutively produced interleukin-1 alpha (IL-1 alpha) and PTH-like factor, the effects of IL-1 alpha and PTH-related protein (PTH-rP) on bone resorption in vitro and on serum calcium concentrations in vivo were investigated. Nude mice transplanted with EC-GI cells invariably developed hypercalcemia, although their urinary cAMP excretion remained within the normal range. IL-1 alpha or PTH-rP-(1-34) stimulated 45Ca release from prelabeled fetal mouse forearm bones in a concentration-dependent manner, and when combined, IL-1 alpha and PTH-rP-(1-34) synergistically stimulated bone resorption in vitro. Injection of PTH-rP-(1-34) into mice three times a day for 2 days increased the serum calcium concentration in a dose-dependent manner. Continuous infusion of IL-1 alpha occasionally increased the serum calcium concentration. Simultaneous administration of IL-1 alpha at rates of 1-2.7 micrograms/day and PTH-rP-(1-34) at doses of 15-30 micrograms/day synergistically increased the serum calcium concentration in vivo. These findings suggest that PTH-rP and IL-1 alpha produced by the tumor cells were synergistically responsible for the humoral hypercalcemia observed in both the original patient and the tumor-bearing nude mice, and that at least two bone-resorbing factors [PTH-rP and another nonadenylate cyclase-stimulating bone-resorbing factor(s)] are active in patients with malignancy-associated hypercalcemia, in whom nephrogenous cAMP excretion is neither increased nor decreased.

The plasma GH response to GH-releasing hormone (GHRH), TRH, or GnRH administration was examined in 25 acromegalic patients. Plasma GH levels increased in 21 patients after GHRH, in 19 after TRH, and in 4 after GnRH. The four GHRH nonresponders had had acromegaly longer than had the GHRH responders. No specific combination of GH responsiveness to these 3 releasing hormones was found among the patients. Infusion of 1 mg GHRH for 150 min gradually increased plasma GH levels, with some fluctuations, from the beginning to the end of infusion in normal subjects and in 7 patients who were GHRH responders, but a bolus injection of 100 micrograms GHRH at the end of the infusion did not further elevate plasma GH levels. These results suggest that desensitization to GHRH occurred in the normal subjects and acromegalic patients. However, in 5 acromegalic patients who responded to both GHRH and TRH, a bolus injection of 500 micrograms TRH given at the end of the 150-min infusion of 1 mg GHRH evoked a further plasma GH rise. In 5 normal subjects and 2 patients who were responders to GHRH but not TRH, a bolus injection of 500 micrograms TRH did not cause plasma GH elevation at the end of 150-min infusion of 1 mg GHRH. These results imply that TRH and GnRH stimulate GH secretion from the adenoma cells in vivo through receptors different from those for GHRH. In vitro studies using cultured pituitary adenoma cells from 2 patients revealed that the responses of GH secretion to GHRH were similar to those in vivo. These data, therefore, suggest that the responsiveness of GH secretion to stimuli is determined by the specificity of the receptors on adenoma cells. The action of somatostatin-28 was more potent than that of somatostatin-14 in the suppression of GH secretion from adenoma cells.

The effect of plasmapheresis on thyroid hormone secretion was studied in the dog. Approximately 10% of body weight volume of blood was exchanged with red blood cells suspended in dextran solution over a period of 10-30 min. A striking increase in thyroid hormone release was observed within 2 hr. Addition of thyroid hormone to the blood cell suspension, however, did not prevent this response. Although the increase in thyroid hormone release was not universally seen in hypophysectomized dogs, in decerebrate dogs and in some hypophysectomized dogs a moderate response was observed. These results suggested the possibility that some mechanism other than pituitary-thyroid feedback might be involved. Since no marked change was observed local perfusion of the thyroid with blood cell suspension, extrathyroidal humoral factors were probably involved in this response. (Endocrinology 86: 1281, 1970)

IN RECENT years the relationship between hormones and the mechanism of pigmentation has come to the fore. In this report it will be shown that the pituitary gland elaborates a melanocyte-stimulating hormone (MSH) which affects melanin pigmentation in man. The “peculiar change” in skin color described by Addison in patients with adrenocortical insufficiency, the decreased pigmentation of panhypopituitarism, and the melasma of pregnancy seem to depend in large part upon the activity of MSH. Because the developments leading to this conclusion have involved many people and many aspects of research, it is worthwhile to review the historical background of this problem. In 1916 Smith and Allen, two biologists working independently, almost simultaneously reported that removal of the pituitary gland of tadpoles was followed by loss of skin color (1–4). Three years later Atwell showed that when tadpoles were immersed in pituitary extracts their skin became darker (5). Atwell, Smith, Swingle, and later Zondek found ...

Summary The responses of plasma HGH during psychiatric shock therapies were investigated, and the mechanisms of HGH secretion and of shock therapies were discussed. 1. The response following a sinall dose of i.v. insulin administrotion. a) The plasma HGH following 0.1 U/kg of i.v. insulin in schizophrenic patients showed marked elevation in six out of seven cases. It reached to the peak value of 30.4±9.2 mμg/ml between 60 and 90 minutes after i.v. insulin. b) This type of response was not affected by the various psychotropic drugs that were administered orally in controlling the mental symptoms of the patients. c) Intramuscular injection of chlorpromazine (30–50 mg) did not alter the pattern of the plasma HGH response. 2. Insulin coma therapy a) A marked elevation of plasma HGH level was observed in all cases of schizophrenia during insulin coma therapy. The peak value was 9–32 mμg/ml (average 22.6±8.1 mμg/ml). b) A tendency of delay in reaching the peak value was observed in the determination performed in the second week of coma days as compared to the initial determination in the early days of insulin coma. A tendency was observed that better therapeutic results were correlated with the absence of or decrease in the delay in reaching the peak value in the course of insulin coma therapy. c) The protracted insulin coma was associated with the marked decrease in the magnitude of the peak value of plasma HGH as compared to the initial determination, suggesting the presence of a fatigued state of the central mechanism regulating the secretion of HGH. 3. Electroshock therapy a) Elevation of the plasma HGH level was observed after electroshock therapy in five of six cases of schizophrenia. A non-responsive case was found to be moderately obese. A case of depression and a case of atypical psychosis lacked HGH response after EST in the absence of obesity. b) The peak value after the electroshock therapy was lower than the one during insulin coma therapy or after administration of a small dose of i.v. insulin. The average peak value after EST was 8.1±6.8 mμg/ml. c) The responsivity of plasma HGH was found to be unrelated to the various prernedications, such as i.v. thiopental and succinylcholine chloride. It was also concluded that the presence or absence of generalized convulsion was not related to the responses of HGH following EST. d) No correlation was found between the changes of blood sugar level and the type of plasma HGH responses following the EST. It was suggested that the elevation of HGH at the time of electroshock therapy was induced by the direct electric stimulation of the hypothalamic center, but the effect of stimulating the HGH secretion was much lower than that induced by the insulin coma or i.v. insulin administration.

The effect of an acute reduction of thyroid hormone level in the circulating blood on thyroid function has been studied in the dog. PBI and free thyroxine index in the blood of a recipient dog were decreased to approximately 70% of their previous levels by means of exchange transfusion from a thyroidectomized-hypophysectomized dog. Thyroid hormone secretion was estimated by determination of PB l31I concentration in thyroid venous blood. No increase in thyroid hormone secretion was observed within 4 hr in either chloralose anesthetized dog or curare immobilized dog. A long-term observation revealed that peripheral blood PBI recovered significantly 2 weeks after exchange transfusion, and free thyroxine index 5 days after. These results suggest that the feedback mechanism does not respond to a moderate reduction of circulating thyroid hormone in the dog immediately, but rather sluggishly over a period of days. (Endocrinology 84: 1161, 1969)

The serum ChE level in the normal persons and the patients of various disease was determined manometrically. The value was expressed in terms of CO2cmm. per 1 min. per 1 cc. serum freed from the Ringer's solution of 0.015M acetylcholine chloride (Roche). 1) Average value of serum ChE in normal persons is 65.4. The variation is from 50 to 90. 2) The serum ChE level in the patients of liver- and neoplastic diseases is low. The decrease of the value is remarkable in the cases of serious damage of the liver and in gastric cancer. The decrease of serum ChE can occur despite the negative results of many liver function tests. The serum ChE level correlates with the results of bromsulfaleine test better than those of other liver function test. 3) In pulmonary tuberculosis, the variation of the serum ChE level is in a very wide range. Serious cases showed very low value, while in others normal or higher level was found. 4) In the cases of the endocrine disturbance, nervous disease or other various diseases, no characteristic change of the serum ChE level was found. However, regardless of the sort of disease, the serum ChE level is low in the serious cases.

A study was made, of 14 acromegalic patients, to correlate the fasting plasma HGH (Human Growth Hormone) concentrations with other indices of activity, such as plasma inorganic phosphorus level, BMR (Basal Metabolic Rate), glucose tolerance test, and clinical impressions. Neither plasma inorganic phosphorus level nor BMR had a correlation with the plasma HGH concentrations. Clinical impressions of activity were in relatively close agreement with the plasma HGH concentrations. Association of diabetes mellitus was not related to either fasting plasma HGH concentrations or the duration of disease. The results of urinary HGH excretion and non-suppression of plasma HGH concentrations following 100 gram glucose administration are also discussed.

Calcium tolerance test and calculation of “Parathyroid Index” was carried out on 8 hyperthyroid and 10 euthyroid subjects. Abnormal parathyroid response to hypercalcemia was observed in hyperthyroid subjects. Functional relationship between thyroid and parathyroid glands was briefly reviewed.

Growth hormone content in the pituitary gland was measured by radioimmunoassay in 48 human fetuses at various gestational stages. None of the fetuses of 6 weeks gestation contained detectable amounts of growth hormone. However, growth hormone was measurable in some fetuses starting at the 7th week, and by the 9th week it was detected in all fetuses studied. Thereafter, growth hormone content increased in excess of the body weight gain. Growth hormone concentration in cord blood was also studied in 7 fetuses. It ranged from 18 ng/ml in a 10-week-old to 120 ng/ml in a 4-month-old fetus. It was concluded that human fetuses synthesize and store growth hormone as early as the 7th gestational week.

ALTHOUGH periodic paralysis is a rare disorder, its association with hyperthyroidism has been reported by several investigators (1–15). In reviewing the literature, it was found that only about 30 such cases have been reported from the United States and Europe, whereas more than 70 cases have been reported from Japan. Possibly the association of these two disorders is less rare in Japan. As the Japanese reports were all concerned with relatively small numbers of patients with hyperthyroidism, the incidence of the association of these two disorders in Japan could not be estimated. In order to obtain a fairly good estimate, the incidence of periodic paralysis among 6,333 cases of hyperthyroidism operated upon in three thyroid hospitals in Japan was studied. These hospitals were located in different parts of country—Noguchi Hospital in Beppu, Kyushu (southern part of Japan), Kuma Hospital in Kobe (central part of Japan) and Ito Hospital in Tokyo (eastern part of Japan), so the study provided data on a cross ...

A study of total exchangeable potassium, sodium and total body water was undertaken in 8 normal subjects, 7 patients with thyrotoxicosis without periodic paralysis, 8 patients with idiopathic periodic paralysis and 7 patients with thyrotoxic periodic paralysis. Our findings show that total exchangeable potassium is modestly but significantly reduced in idiopathic periodic paralysis, but within normal limits in thyrotoxic periodic paralysis.

In order to observe the alterationsin intrathyroidal iodine metabolism which occur in response to chronic iodide administration, iodine metabolism in rats given 500 µg of iodide/ day (iodide group) was compared to that in rats given 10 μg of iodide/day (control group). Ratswere given 126I with 127I in their drinking water for 4 weeks until the time of sacrifice. Rats were also injected with 131I and killed at various time intervals up to 48 hr after 131I. In the 2 groups, thyroidal 127I content and serum iodothyronine- 127I concentrations did not differ significantly from each other, while absolute iodine uptake calculated from thyroidal clearance of 131I multiplied by the serum 127I concentration was 2.5 times greater in the iodide group than in the control. With respect to both m I and 131I, the. proportion of iodothyronines as a per cent of total thyroidal organic iodine did not differ greatly in the 2 groups. This indicated the apparently contradictory results that the iodide group took up 2.5 times a...