Search

Changes in the membrane potential and the intracellular Ca2+ concentration ([Ca2+]i) caused by somatostatin (SRIF) were simultaneously measured in human GH-producing pituitary tumor cells, by means of the nystatin-perforated whole cell clamp technique and Fura-2 AM. An application of 10(-8) M SRIF hyperpolarized the membrane and arrested Ca(2+)-dependent spontaneous action potentials. [Ca2+]i concurrently decreased during membrane hyperpolarization. When the membrane potential was clamped below the threshold for voltage-gated Ca2+ channels, [Ca2+]i decreased and SRIF did not further reduce [Ca2+]i. In cells which did not show spontaneous action potentials, SRIF hyperpolarized the membrane but it affected [Ca2+]i little. From these results it was concluded that the reduction in [Ca2+]i caused by SRIF was ascribed to the decrease in Ca2+ influx through voltage-gated channels during membrane hyperpolarization. The effect of SRIF on the voltage-gated Ca2+ channel current was also examined under the perforated whole cell clamp. SRIF (10(-8) M) inhibited the Ca2+ channel current to 80.8 +/- 15.4% (n = 5) of the control. Because SRIF-induced inhibition of the voltage-gated Ca2+ channel current was not prominent, it was considered that membrane hyperpolarization is the major cause of the reduction in [Ca2+]i in human GH-producing cells.

Serum intact parathyroid hormone (PTH) concentration was measured by a two-site immunoradiometric assay (IRMA) in normal subjects and patients with various parathyroid disorders. Serum intact PTH levels were all within the detection limit of the IRMA in normal subjects, and there was a significant negative correlation between serum calcium (Ca) and intact PTH levels. Although 3 out of 26 patients (11.5%) with primary hyperparathyroidism had a normal serum intact PTH concentration, these patients could be readily discriminated from normal subjects by plotting serum intact PTH against the serum Ca concentration. In contrast, serum intact PTH was undetectable in 16 out of 17 patients (94.1%) with idiopathic hypoparathyroidism. Patients with pseudohypoparathyroidism (PHP) type I, mostly under treatment with active vitamin D, exhibited wide distribution of serum intact PTH concentration, and appeared to belong to two distinct subgroups. One group of patients demonstrated a similar relationship between serum intact PTH and Ca levels to normal subjects. The other exhibited much higher serum intact PTH levels despite a normal serum Ca concentration, and no obvious relationship could be observed between the two parameters. These results demonstrate that an inverse relationship between serum Ca and intact PTH can be demonstrated in normal subjects with normocalcemia, that most of the parathyroid disorders can be diagnosed by measuring serum Ca and the intact PTH concentrations simultaneously, and that patients with PHP can be divided into two subgroups: one with a normal relationship between serum Ca and intact PTH, and the other with a high serum PTH level in the face of normocalcemia.

The usefulness of spot determination of urinary cortisol in the screening of Cushing's syndrome was evaluated by measuring the cortisol concentration in randomly sampled urine in 68 normal subjects and in 9 patients with Cushing's syndrome. The urinary cortisol concentration in the morning was significantly higher in patients with Cushing's syndrome but some overlap existed between normal subjects and patients with Cushing's syndrome. In contrast, there was a clear discrimination between two groups when urinary cortisol was measured in the late evening: urinary cortisol was lower than 75 micrograms per gram creatinine (microgram/gCr) in normal subjects but higher than 150 micrograms/gCr in patients with Cushing's syndrome. When 1 mg dexamethasone was administered at 2300 h in the evening, spot urinary cortisol the next morning was less than 80 micrograms/gCr in normal subjects while it was above 100 micrograms/gCr in patients with Cushing's syndrome. Dexamethasone-induced suppression of urinary cortisol in normal subjects lasted until late in the afternoon, which allows sampling of urine at any time in the morning and possibly in the afternoon. These results suggest the usefulness of spot determination of urinary cortisol in the screening of Cushings' syndrome.

In vitro responsiveness to various stimulators of aldosterone secretion was studied in a perifusion system using slices obtained from three aldosterone-producing adenomas (APAs), three adjacent nontumorous glands and three normal adrenal glands. All three APA tissues responded to angiotensin II, K and ACTH in vitro. Angiotensin II (10 nM), K (12 mM) and ACTH (10 nM) caused more than a 2-fold increase in aldosterone secretion. The sensitivity of APA tissues to angiotensin II was identical to that in normal adrenal cortex. In slices obtained from APA, angiotensin II induced rapid increases in [3H]inositol and [45Ca] efflux, both of which preceded the aldosterone response. These results suggest that APA cells have an almost normal transducing system to stimulators of aldosterone secretion.

To determine the interrelationship between muscle dysfunction and a low T3 state, both seen in anorexia nervosa, we studied the relationship between the degree of muscle involvement, as assessed by the circulating concentration of the three muscle indicators (CPK, GOT and LDH), and serum T3 in thirty-three patients when they were admitted to the hospital. We also studied the malnutritional state, as assessed by their body weight or serum GH, serum potassium and the degree of hyperactivity exhibited. Additionally, another twelve patients were studied in order to explore the mounding phenomenon which is typically elicited in hypothyroidism. The logarithms of serum CPK and GOT correlated only with the serum T3 concentration (r = -0.35, p less than 0.05; r = -0.41, p less than 0.05; respectively). The logarithm of serum LDH highly correlated with serum T3, the percentage of ideal body weight, and the logarithm of serum GH (r = -0.55, p less than 0.01; r = -0.66, p less than 0.001; r = 0.43, p less than 0.05; respectively). The mounding phenomenon was elicited in ten out of twelve patients. In conclusion, it was implied that a low T3 state was associated with an increase in serum muscle indicators and thus with muscle dysfunction encountered in anorexia nervosa.

Studies on the electrolyte metabolism and the renin-angiotensin-aldosterone system were made in a 47-year-old female patient with factitious Bartter's syndrome induced by surreptitious use of furosemide. The diagnosis was confirmed later by detection of the diuretic in the urine. In metabolic studies patient exhibited abnormalities similar to those reported in Bartter's syndrome; viz, hypokalemic alkalosis, blunted response to exogenous angiotensin II, which reverted to normal by volume expansion with an albumin solution, and diminished fractional free water clearance per fractional distal sodium delivery. The above data, along with the known pharmacological effects of furosemide, suggest that the abnormality in Na+ or Cl- reabsorption in the ascending limb of Henle's loop is a primary cause of Bartter's syndrome.

In an attempt to clarify the underlying mechanism(s) in the disappearance of phosphaturic response to bolus parathyroid hormone (PTH) in hyperparathyroid patients, the effects of bolus bovine PTH (10 USP U) were studied in conscious thyroparathyroidectomized (T . PTX) male Wistar rats that had been infused with a dose of PTH (2.5 U/hr, for 16 hours) so as to reproduce hyperparathyroidism. These animals responded with an increase in urinary cyclic AMP, but without an increase in renal clearance of phosphate. The loss of phosphaturic response was not prevented by pretreatment with actinomycin D at a dosage close to full toxicity (0.1 mg/kg BW, ip, for 3 days). Actinomycin D at this dosage did not affect the normal stimulatory effects of bolus PTH on urinary cyclic AMP and renal clearance of phosphate in T . PTX rats. The continuous infusion of PTH produced nearly maximal phosphaturia throughout in the face of a significant depletion of phosphate. In addition, pretreatment with actinomycin D did not cause a further increase in urinary phosphate excretion during the infusion. These results, along with the report of Shah et al. (1979) indicating that the development of antiphosphaturic adaptation to acute phosphate depletion was prevented by comparable amounts of actinomycin D, indicate that the disappearance of phosphaturic response to bolus PTH by prior PTH infusion simply signifies the continuation of maximal phosphaturic response to the preceding PTH infusion. It is also suggested that the continuous action of PTH prevents, at least phenomenologically, the development of the gene-activation-mediated refractoriness to PTH or antiphosphaturia induced by acute phosphate depletion.

In this report on two cases of anorexia nervosa associated with Graves' disease, metabolism and the relationship between the two illness are considered. Case 1 was a 25-year-old female. Anorexia was associated with a stressful life situation following marriage. One year after the onset of anorexia, her condition was diagnosed as Graves' disease. In spite of high levels of serum thyroid hormone, she did not show the clinical signs and symptoms of hyperthyroidism. The hypermetabolic state of Graves' disease seems to be suppressed by the hypometabolism of anorexia. Case 2 was a 17-year-old female whose body weight, due to anorexia, at one time had decreased from 55 kg to 35.2 kg. A rebound from anorexia to bulimia increased her body weight to 80 kg in spite of an association with the hypermetabolic state of Graves' disease. In light of the abovementioned cases, it seems that the clinical picture of Graves' disease is usually hidden by the clinical symptoms of anorexia nervosa.

A 23-year-old man with primary hyperparathyroidism which was typical except for reduced alkaline phosphatase activity is reported. Histological examination of surgical specimens revealed chief cell hyperplasia of the parathyroid glands. Systemic abnormalities of alkaline phosphatase were demonstrated, i.e., marked reduction of all isoenzymes and undetectable osseous enzyme in the serum, abnormal distribution of the enzyme in hepatocytes and diminished enzyme activities in leukocytes. In addition, diminished bone remodeling activity was revealed in a biopsy specimen of the rib. The association of hypophosphatasia is highly unlikely, because of normal urinary excretion of phosphoethanolamine, lack of osteomalacia, and no indication of an hereditary factor. The causal relationship between low remodeling activity and abnormalities in alkaline phosphatase was suggested.

In an attempt to verify the importance of calcium ions in mediating alpha -adrenergic stimulation, the effects of a calcium channel blocker, verapamil, on phenylephrine-induced glycogenolysis and calcium efflux in perfused livers prepared from fed rats were determined. The blocker inhibited phenylephrine-induced glycogenolysis in a noncompetitive and dose-dependent manner between 50 micro M and 500 micro M. However, it did not affect 2, 4-dinitrophenol-induced glycogenolysis. It had no significant effect on 45 Ca uptake by the perfused liver, but inhibited basal as well as phenylephrine-induced efflux of 45Ca from 45Ca-loaded liver. The inhibitory effects on basal 45Ca release and phenylephrine-induced glycogenolysis and 45Ca released correlated very well. All the the effects of verapamil were reproduced by another calcium channel blocker, diltiazem, suggesting that these effects are common to a variety of calcium channel blockers. These results indicate that the process of calcium influx and the function of phosphorylase per se are not directly involved in the inhibitory action of the blocker. Although it is possible that verapamil interferes with binding of the alpha -adrenergic agonist to the plasma membrane, the good correlation between the inhibitory effects of verapamil on basal 45Ca released and on phenylephrine-induced release of 45Ca suggests another mechanism, involving calcium ions. The blocker appears to inhibit the glycogen phosphorylase activity induced by phenylephrine via a cell-membrane mechanism in which calcium ion flux changes are intimately involved.

A female patient with classical gonadal dysgenesis associated with Graves' disease is reported. The karyotype was mosaicism of 45,X/46,X,i(Xq). The relationship among Graves' disease, Hashimoto's thyroiditis and Turner's syndrome is discussed along with a review of the reported cases.

The effects of intravenous salmon calcitonin on tissue carbohydrate and redox metabolism were studied in rat kidney in situ and were compared to the effects of EGTA infusion. Calcitonin (0.8 MRC U, in bous) caused, after 10-20 min, a reductive shift of the cytosolic NAD redox pair, and an oxidative shift of the mitochondrial NAD redox pair. It also caused a stimulation of glycolysis with the cross-over between phosphoenolpyruvate and pyruvate. These results were reproduced by treatments of hypocalcemia with EGTA or with thyroparathyroidectomy. Most of the effects were opposite in direction to the reported effects of CaCl2 and parathyroid hormone. The above results suggest that in kidney calcitonin causes a stimulation of pyruvate kinase, and/or inhibition of phosphoenolpyruvate carboxykinase, and that the effects are related to changes in the intracellular calcium.

The effects of high-fiber diet on the metabolic states in streptozotocin-induced diabetic rats were investigated. The animals were divided into three groups: group A fed on a diet containing 5% of fiber (bagasse), group B paired-fed on a control diet and group C fed on a control diet ad libitum. The body weight gain was greater and the fasting blood sugar level was lower in A than B and C. The plasma triglyceride level was lowest in A, while no significant difference in the serum total cholesterol level was observed between A and B. Plasma glucagon levels were decreased in A and increased significantly in B and C. Plasma insulin levels were not changed in these groups. These results support the theory that a high-fiber diet is an effective therapeutic regimen for the control of metabolic derangement in diabetics.

In an attempt to study the influence of vitamin D metabolites on PTH secretion, serum calcium and urinary excretion of cAMP were sequentially measured in conscious perfused rats, and the effects of a single iv injection of the metabolites on these parameters were examined. Four hours after the administration of 0.25 microgram/kg (0.6 nmol/kg, probably a physiological dose) of 1 alpha, 25-dihydroxycholecalciferol [1 alpha, 25 (OH)2D3], the urinary excretion of cAMP decreased to a level compatible with that of parathyroidectomized rats (approximately 60% of the initial value; P less than 0.05) and this level was sustained for nearly 24 h. Serum concentrations of calcium (total and ionized) did not change. In parathyroidectomized rats which were continuously infused with bovine PTH (1 U/h), the vitamin D metabolite had no significant effect on the urinary excretion of cAMP. 24 R, 25-dihydroxcholecalciferol (12.5 microgram/kg) had no significant effect either on the urinary excretion of cAMP or on serum calcium. These results suggest that in rats, a physiological dose of 1 alpha, 25(OH)2D3 inhibits PTH secretion without causing a significant rise iu serum calcium, reflecting a feed-back mechanism between active vitamin D metabolite, 1 alpha, 25(OH)2D3 and the parathyroid glands.

The mode of involvement of sex steroids in the growth spurt during adolescence was studied in Wistar rats with a special reference to the level of serum somatomedin A (SMA) determined by radioreceptor assay. Intramuscular administration of testosterone propionate (T; 1 mg/day, alternately for 10 days) to female or gonadectomized male rats provoked a small but significant increase in their body weight or body length without affecting the serum SMA level. In contrast, in hypophysectomized (hypox) male rats T caused a considerable increase in body weight and the serum SMA level only when administered concurrently with bovine growth hormone (bGH; 0.2 U/day, ip). T did not affect the sulfation activity in vitro. These results suggest that androgen participates in the growth spurt during adolescence by enhancing the SMA effect and/or potentiating the SMA production by GH. Estradiol benzoate (E2; 100 micrograms/day, alternately for 10 days) caused a decrease in the serum SMA level and the growth rate in normal male rats. However, E2 produced an increase in the SMA level when administered to hypox male rats, although the growth was retarded and sulfation potency of the serum was sharply reduced. These results indicate that E2 may suppress the growth by lowering SMA generation in normal rats and cause a production of biologically inactive SMA in hypox male rats.

The effects of intravenous carrier-free salmon calcitonin on renal clearances of phosphate, calcium, magnesium, sodium and potassium were studied in male parathyroid-ectomized (PTX) and intact rats. Both natural and synthetic hormone, when infused at constant rates (0.005 approximately 0.5 MRC U/hr), produced a rapid increase (peaking at about 60-90 min) in phosphate clearance. However, the maximal increase was transient in nature in PTX rats. In intact rats, the phosphaturic response was somewhat more pronounced and the decline after the peak was rather modest. When a large amount (4 MRC U) of calcitonin was given in divided doses, the second dose produced a lesser extent of phosphaturia in both intact and PTX rats. The phosphaturic response was accompanied by an increase in sodium and potassium clearances in PTX rats and by an increase in potassium clearance in intact rats. A fall in the apparent clearance values for calcium and magnesium occurred and was maintained throughout the infusion period of hormone in both intact and PTX rats. In conclusion, PTX rats respond to the intravenous administration of salmon calcitonin with a transient phosphaturic response which is accompanied by parallel diuresis of sodium and potassium along with sustained retention of calcium and magnesium by the kidney.

A 22 year old man with two extra-adrenal pheochromocytomas located in the mediastinum and in the pelvis is presented. We believe this is the first report in Japan of extra-adrenal multiple pheochromocytomas in adult located in the two distant places.

A 57-year old woman with thyroid carcinoma manifesting overt thyrotoxicosis is presented. After the patient had been made euthyroid with propylthiouracil, right lobectomy and lymph node dissection were performed. Permanent paraffin sections revealed follicular adenocarcinoma with capsular and vascular invasion. Metastases to the right humerus, both femurs, the skull and pleural cavity became prominent with the recurrence of thyrotoxicosis and the patient died 2 years and 3 months after operation. The clinical evidence indicates that thyrotoxicosis in the present case is caused by the excessive secretion of thyroid hormone by both the original carcinoma and the secondary deposits. Twenty three similar cases reported in the English and Japanese literatures are summarized.

A calcium ionophore (A-23187, 20 mug/ml) stimulted 14C-1-glucose oxidation in dog thyroid slices to an extent equivalent to that obtained by the optimal concentration of dibutyryl cyclic AMP (1mM). Furthermore, the ionophore augmented the stimulation by dibutyryl cyclic AMP much more than the simple additive effect. The ionophore also enhanced the effect of TSH, but to a lesser extent. Under conditions where organic binding was blocked, T/M ratio of radioiodine concentration was lowered in slices by the ionophore; the findings similar to those obtained with TSH and dibutyryl cyclic AMP. The ionophore exhibited a slightly depressive effect on the basal cyclic AMP level. The elevation by TSH of cyclic AMP levels was also slightly depressed by the ionophore, but statistically insignificant in most cases. These results indicate that calcium ion may play an important role in the TSH regulation of iodide transport and glucose metabolism in the thyroid, in some cases by augmenting the effects of cyclic AMP.

A patient with Graves' disease who experienced various allergic reactions to both PTU and MMI is reported. She developed fever, skin rash, lymphadenopathy, liver damage and moderate leukopenia during PTU administration. Furthermore, she developed an MMI-induced lupus-like syndrome characterized by generalized lymphadenopathy, migrating, polyarthritis and myalgia, and results of tests for anti-DNA antibody and anti-nuclear antibody, and LE were positive. All these abnormalities reverted to normal upon discontinuation of medication after subtotal thyroidectomy.

Treatment with concanavalin A at 100 micron/ml or higher concentrations significantly increased 14C-1-glucose oxidation in dog thyroid slices as reported in other tissues. This treatment exerted no effect on tissue cyclic AMP levels. Neuraminidase at the same concentrations also had similar effects on these parameters. Neither concanavalin A nor neuraminidase at the concentrations up to 100 microng/ml had the TSH effect on both tissue cyclic AMP and 14C-1-glucose oxidation. These results indicate that modification of carbohydrate moieties of glycoproteins on the cell surface may cause an increase in glucose metabolism without any critical effect on cyclic AMP system and in the process of TSH response.

Two postpartum and 7 spontaneous episodes of transient hypothyroidism developed during 5 years of observation in a florist with autoimmune thyroiditis and seasonal allergic rhinitis. The spontaneous episodes recurred twice a year regularly in spring and in autumn, the seasons of her allergic rhinitis. In most of these episodes as well as in the postpartum ones, hypothyroidism was preceded by transient thyrotoxicosis. In addition to the similarity in the clinical course, the changes in antimicrosomal antibody titers in pregnancy-unrelated episodes were almost identical to those in postpartum episodes. Throughout the observation periods, she had supranormal serum total immunoglobulin (Ig) E concentrations and high antigen-specific Ig E levels for various pollen extracts such as cedar and ragweed. However, we failed to demonstrate a correlation between thyroid function and total or any antigen-specific Ig E level. The present findings suggest that the pregnancy-unrelated thyroid dysfunction in our patient developed as a result of silent thyroiditis and through similar immunological mechanisms to those in postpartum thyroiditis. And it is suspected, though unproved, that the seasonal recurrence of pregnancy-unrelated thyroiditis has some causal relation to her allergic disease.

35S incorporation into embryonic chick pelvic cartilage was measured using the method of somatomedin bioassay and the effects thereupon of the bovine parathyroid extract (PTE) and the synthetic [Asu1,7]-eel calcitonin (CT) were examined. Bovine PTE potentiated 35S incorporation stimulated by normal human serum. [Asu1,7]-eel CT did not affect the sulfation activity in the presence of normal human serum. However, it showed a slight stimulation of 35S incorporation in the absence of normal human serum. No definite interaction on 35S incorporation between PTE and CT was observed. It is speculated from these results that PTH may be involved in the stimulation of the cartilage growth in concert with somatomedins in vivo.

The effects of intravenous carrier-free salmon calcitonin on renal clearances of phosphate, calcium, magnesium, sodium and potassium were studied in male parathyroidectomized (PTX) and intact rats. Both natural and synthetic hormone, when infused at constant rates (0.005 approximately 0.5 MRC U/hr), produced a rapid increase (peaking at about 60-90 min) in phosphate clearance. However, the maximal increase was transient in nature in PTX rats. In intact rats, the phosphaturic response was somewhat more pronounced and the decline after the peak was rather modest. When a large amount (4 MRC U) of calcitonin was given in divided doses, the second dose produced a lesser extent of phosphaturia in both intact and PTX rats. The phosphaturic response was accompanied by an increase in sodium and potassium clearances in PTX rats and by an increase in potassium clearance in intact rats. A fall in the apparent clearance values for calcium and magnesium occurred and was maintained throughout the infusion period of hormone in both intact and PTX rats. In conclusion, PTX rats respond to the intravenous administration of salmon calcitonin with a transient phosphaturic response which is accompanied by parallel diuresis of sodium and potassium along with sustained retention of calcium and magnesium by the kidney.

In an attempt to elucidate the dopaminergic involvement in the regulation of the effect of angiotensin II on the adrenals, plasma aldosterone response to angiotensin II infusion (5 ng/kg/min, for 60 minutes) was studied in five normal volunteers in various experimental conditions. Prior infusion of dopamine (3 micrograms/kg/min) or saline (1000 ml/hour) caused an attenuation of the aldosterone response to angiotensin II. Concurrent infusion of a dopaminergic antagonist, metoclopramide (10 micrograms/kg/min), abolished the inhibitory effect of dopamine and saline. These results suggest that the dopaminergic mechanism is involved in the adaptive aldosterone response of the adrenal to acute saline loading in man.