ACTH potentiating activity was found in rat serum. The extract, obtained from ACTH-free rat serum by the QUSO G 32 adsorption method, potentiated ACTH_1-24-induced corticosterone production in isolated rat adrenal cells. In our assay system, the maximal potentiation was observed with the extract of 0.5 ml of rat serum. With the extract, the log dose response curve for ACTH_1-24 shifted to the side of lower doses of ACTH_1-24. The potentiating substance was stable in the serum: the activity was hardly decreased even after leaving the serum stand for six days at room temperature. On Sephadex G-100 gel filtration of the extract, the most of activity was found between about 40, 000 to 9, 000 in molecular weight and a small portion of the activity was in the range of lower molecular weight. After hypophysectomy, the potentiating activity found in the fractions was markedly decreased, but a part of the activity still remained 30 days after the operation. This result suggests that the potentiating substance is produced mainly by the pituitary, but also produced by the other organ (s). SDS polyacrylamide gel electrophoresis of the active fractions revealed five peptides which were decreased quantitatively by hypophysectomy.

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A 24 year old woman with post-surgical hypoparathyroidism was studied during pregnancy and lactation. During pregnancy the patient required less vitamin D therapy for control of her hypoparathyroidism and, while lactating, maintained a normal serum calcium without any supplemental vitamin D.The serum parathyroid hormone concentration and plasma 1, 25 (OH)₂ vitamin D concentration were undetectable and low normal respectively at a time when the serum calcium concentration was normal and the patient was not on vitamin D therapy. Urinary calcium excretion was low during this period and may explain the normalization of the serum calcium. The mechanism by which the improvement in calcium metabolism occurred is unknown, but may be secondary to a direct effect of prolactin on calcium homeostasis.

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When we use Scatchard analysis for insulin receptor on intact cells, internalization of insulin may affect the Scatchard analysis. In this study, results from Scatchard analysis for insulin receptor on hepatocytes of streptozotocin (STZ)-induced diabetic rats were compared with those from association and dissociation studies and those from Scatchard analysis using hepatocyte membrane which does not internalize insulin.
Insulin binding was increased in both hepatocytes and the membranes from STZ-treated rats. Scatchard analysis revealed that both the receptor number and affinity constant were increased. In the dissociation study, the increase in the affinity constant was revealed to be due to a decrease in the dissociation rate constant. The association rate constant was comparable in STZ and control rats. The Scatchard plot was more concave in STZ rats than in controls, suggesting that the magnitude of the negative cooperative effect was greater in STZ rats. This was confirmed by measuring the dissociation rate constant in the presence or absence of unlabeled insulin. Increases in the receptor number, affinity constant, and negative cooperative effect in STZ rats were observed both in hepatocytes and in hepatocyte membranes.

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Using cultured normal rat chondrocytes we have investigated 1) the effects of somatomedin and insulin on glycosaminoglycan (GAG) synthesis and 2) somatomedin and insulin binding sites.
We confirmed that somatomedin and insulin stimulate GAG synthesis in normal rat chondrocytes. The maximal responses of somatomedin and insulin in GAG synthesis were the same, but the stimulation of GAG synthesis by maximally effective concentrations of insulin plus somatomedin was not cumulative. Cultured rat chondrocytes had binding sites for somatomedin and insulin, and the binding was displaced by both somatomedin and insulin. Somatomedin is much more effective than even large amounts of unlabelled insulin in displacing both somatomedin and insulin binding. Anti-insulin receptor IgG, which inhibits insulin binding to human placental membrane, did not affect GAG synthesis stimulated by insulin nor did it inhibit insulin binding to chondrocytes.
Somatomedin used for GAG synthesis and displacement was the partially purified somatomedin A with a biological activity of 80 U/mg. Therefore the possibility that substances other than somatomedin A, which was contaminated in this preparation, affected this result could not be excluded completely. However, these results suggest that somatomedin and insulin act on normal rat chondrocytes through a somatomedin receptor.

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This report describes the specific cytotoxicity of iodoacetic acid (IAA) in selectively destroying the fibroblastoid cells and stimulating the in vitro function of neonatal B cells prepared from rat pancreases. Under culture conditions with a basal medium containing 5.5mM D-glucose alone, the responses to insulin secretagogues tested were abolished by day 7 of culture. In contrast, the addition of 10μM IAA enhanced either insulin release evoked by D-glucose (16.7mM), L-leucine (10mM) and 2-ketoisocaproate (10mM) or the cellular insulin content to approximately twice the initial levels (day 0). L-Glutamine (10mM) augmented the stimulatory effect of L-leucine or 2-ketoisocaproate. Moreover, the continuous application of IAA significantly increased the rates of glutamine oxidation in endocrine cells after 7 days of culture. On the other hand, the IAA-supplemented medium did not preserve the function of A cells. The phase-contrast microphotograph examination revealed the selective removal of fibroblasts from the monolayer cultures. This corresponded very closely with a remarkable reduction in culture DNA content.

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A T₄ suppression test involving 24-h thyroidal ¹³¹I uptake was carried out on patients with Graves' disease during therapy with an antithyroid drug.Thirty-three patients received propyithiouracil (PTU) for at least 1 year. Each patient was given 75 μg L-T₃ daily for 8 days in conjunction with PTU (50 mg/day) at the time of the experiment and then the 24-h thyroidal ¹³¹I uptake (post T₃ uptake was measured).Twenty-two patients had normal levels of serum T₃ and T₄-I before L-T₃ administration and were divided into 2 groups, positive T₃ suppression (post T₃ uptake ≤ 35%, group I) and negative T₃ suppression (post T₃ uptake> 35%, group II).Eleven patients showed elevated serum T₃ or T₄-I concentrations before L-T₃ administration (group III).The T₄ suppression test was then performed on the same patients.Each patient was given 300 μg L-T₄ daily for 8 days in conjunction with PTU and the 24-h thyroidal ¹³¹I uptake (post T₄ uptake) was measured.Some patients receiving PTU (50 mg/day) were switched to MMI (5 mg/day) and the T₄ suppression test was done one month later.A significant correlation between the two suppression tests during PTU therapy was observed (r 0.961, p<0.01).None of the patients complained of side effects during the T₄ suppression test.The mean post T₄ uptake in group I was 18.8±3.3% during PTU therapy and 5.4±1.3% during MMI therapy.The mean post T₄ uptake in group III was 53.5±.7.0% during PTU therapy and 16.4±5.8% during MMI therapy.
The present findings indicate that the T₄ suppression test with the lower toxicity reported herein is equivalent to the conventional T₃ suppression test.However, it appears to be difficult to evaluate the results of the T₄ suppression test on the basis of the 24-h uptake during MMI therapy.

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Five healthy adult men were given metoclopramide (10mg and 20mg) iv and the effects of L-dopa and dexamethasone on metoclopramide-induced increases in the plasma pregnenolone concentration were determined. After an injection of 10mg metoclopramide, the pregnenolone level rose slightly, though not significantly vs a control. After injecting 20mg metoclopramide, the pregnenolone level rose significantly vs both the control and the basal level. The pregnenolone increase was not inhibited by L-dopa pretreatment, whereas pretreatment with dexamethasone did suppress it significantly. The data suggest that metoclopramide increases pregnenolone secretion through an ACTH-dependent effect and that dopamine does not modulate pregnenolone secretion in man. This means that dopaminergic modulation does not affect the early steps (cholesterol to pregnenolone) of steroid biosynthesis in man.

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After incubation of various tritiated C-19 steroids (androstenedione, testosterone, dehydroepiandrosterone, dehydroepiandrosterone sulfate) with human fetal liver, adult liver and hepatoma tissue homogenates, estrone, estradiol and estriol were analysed after a series of purification steps involving column chromatography, thin layer chromatography and co-crystallization. The findings indicated that the human fetal liver extensively aromatized various C-19 steroids to estrogens, whereas human adult liver and hepatoma tissues exhibited little or no aromatase activities.
The formation of estradiol from androstenedione in human fetal liver indicated the presence of 17β-hydroxysteroid dehydrogenase in this tissue.
It was therefore concluded that although the liver participated in the aromatization process during the fetal stage, extensive aromatization did not take place in the adult liver.

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In order to elucidate the relationship between cyclic AMP and the Ca²⁺-calmodulin system in the steroidogenic response to adrenocorticotropic hormone (ACTH), the effects of calmodulin inhibitors (trifluoperazine and W-7) on cortisol production and cellular cholesterol ester hydrolysis induced by ACTH or dibutyryl cyclic AMP in bovine adrenocortical cells were examined in the absence of extracellular Ca²⁺. These calmodulin inhibitors inhibited not only the cortisol production and the cholesterol ester hydrolysis induced by ACTH in the absence of extracellular Ca²⁺, but also inhibited the dibutyryl cyclic AMP-induced cortisol production and the cholesterol ester hydrolysis in the absence of extracellular Ca²⁺. These results suggested the possibility that cyclic AMP action was mediated by the Ca²⁺-calmodulin system in the activation process of cellular cholesterol ester hydrolysis in the steroidogenic response to ACTH.

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Since C-peptide immunoreactivity (CPR) is excreted at a much higher rate than insulin in the urine, the urinary CPR (U-CPR) level could be a good measure of pancreatic B-cell function. In 10 normal subjects and 17 patients with non insulin-dependent diabetes mellitus (NIDDM), the 24-hour U-CPR level was 49.6 ± 4.5 (mean ± SE)μg, and 59.1 ±7.9 μg, respectively. When measured repeatedly during 4-37 consecutive days, the mean levels of coefficient of variation (c.v.) of 24-hour U-CPRs in each individual in normal and diabetic patients were 23.4 ± 3.2%, and 39.1 ± 1.2%, respectively. Thus, the daily fluctuation of U-CPR was considerably large not only in NIDDM but also in normal healthy sub jects. In order to investigate factors responsible for these U-CPR variations, we analyzed the effect of food constituents on U-CPR excretion in this paper. In 8 healthy subjects 5-hour U-CPR excretions were measured after ingesting 5 kinds of isocaloric 300 kcal test meals, i.e. glucose, starch, protein, fat, and mixed meal which consisted of equal kcal of starch, protein and fat. Five hour U-CPR excretion after glucose, starch and protein meal ingestion was 9.5 ± 1.3 μg, 13.7 ± 1.9 μg, and 7.4 ± 0.9 μg, respectively. Fat meal induced no increase in U-CPR excretion. After the mixed meal ingestion, 5-hour U-CPR was 8.2 ± 0.6 μg, which was approximately the mathematical average for the U-CPR after 3 meals. We conclude that the cause of variations in the U-CPR excretion may be ascribed not only to the ingested total calories, but also to the nutritional components of the diet. Therefore, care must be taken in reading a daily U-CPR measurement in assessing pancreatic B cell function.

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A transplantable tumor CUB-II, a subline derived from the Dunning R 3327 rat prostatic adenocarcinoma, contains a unique sex steroid-binding protein. The protein possesses binding sites for androgens as well as for estrogens, and the binding affinity to androgen is higher than that to estrogen. The sedimentation coefficient of the protein is 10S. Sodium thiocyanate inhibits the binding to both sex steroids. This type of binding is not present in the 0.4 M KCl extract of nuclei. These results suggest that the binding protein is not the receptor for steroid hormones in spite of its high affinity binding to androgens and estrogens. Since the original tumor does not contain such protein, production of this binding protein seems to take place during culture in vitro and/or serial transplantations of the tumor.

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The effect of calcium ion on 3, 5, 3'-triiodothyronine (T₃) binding to rat kidney outer mitochondrial membranes was examined in vitro. The outer mitochondrial membranes were prepared by using a discontinuous sucrose density gradient centrifugation. The membrane fraction, which is enriched with monoamine oxidase activity, contained specific binding sites for T₃. Scatchard analysis of T₃ binding to outer mitochondrial membranes gave an association constant (Ka) of 0.53 × 10¹⁰M^-1. The binding of [¹²⁵I]-T₃ to the membranes was inhibited by the addition of CaCl₂ (0.25 × 10^-4-2.5 × 10^-3M). 50% inhibition was obtained by 0.75 × 10^-4M CaC1₂ in the presence of 0.1 mM EGTA. When outer mitochondrial membranes were solubilized with Triton X-100, four main T₃ binding activities were isolated by a gel filtration study. On the other hand, the binding of [¹²⁵I]-T₃ to the solubilized T₃ receptors derived from outer mitochondrial membranes was not strongly inhibited by calcium.
When outer mitochondrial membranes were preincubated in the presence of 1 mM calcium, the number of T₃ binding sites in the membranes was decreased, and this was associated with an increase in the number of T₃ binding sites in the supernatants of the incubation mixture. Scatchard analysis showed that the number of T₃ binding sites in the membranes is decreased by calcium ion without any change in the association constant. In studies with gel filtration of receptors which are released by Ca²⁺ from outer mitochondrial membranes, three main T₃ binding activities were isolated. Mg²⁺, Mn²⁺, Zn²⁺ and Cu²⁺ did not affect T₃ binding to outer mitochondrial membranes.
The results indicate that calcium ion regulates T₃ binding to the outer mitochondrial membrane through the release of T₃ receptors from the membranes.

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We compared A-14 and A-19 ¹²⁵I-labelled insulin in receptor-binding and degradation. Percent receptor-binding of A-14 and A-19 ¹²⁵I-labelled insulin to 2.4×10⁹/ml erythrocytes after 210 min incubation at 15°C was 7.8 and 4.9%, respectively. Percent insulin-receptor binding of A-14 insulin was 1.6 times greater than that of A-19 insulin. A similar result was obtained in an adipocytes insulin binding study. Percent receptor-binding of A-14 and A-19 insulin to 2 × 10⁵/ml fat cells after 30 min incubation in the above buffer was 3.9 and 2.4%, respectively. Degradation of A-14 and A-19 insulin in rat adipocytes was also studied by molecular sieve column chromatography. Isolated rat adipocytes were allowed to associate with A-14 and A-19 ¹²⁵I-insulin for 60 min at 37°C, pH 8.0 in a HEPES-phosphate buffer, and then cells were separated from the buffer by centrifugation. After solubilization with triton X-100, both the solubilized cells and the incubation medium were applied to the Bio-Gel P-30 column to assess the insulin degradation. Degradation of A-14 ¹²⁵I-insulin by the isolated rat adipocytes was 1.6 times greater than that of A-19 ¹²⁵I-insulin. Furthermore, the peak which was thought to be intermediate degradation products of insulin was obtained between the peak of intact insulin and that of ¹²⁵I-tyrosine. Such a peak of intermediates was much smaller in the incubation media than in the cell-associated materials. Since insulin was mostly degraded by the receptor-mediated process in rat adipocytes, these results suggested that iodination at the A-19 region of insulin affected receptor-mediated insulin degradation due to decreased affinity for insulin receptors.

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The binding of human calicitonin (CT) was investigated in the plasma membrane fraction obtained from normal rat liver. The liver plasma membrane bound ¹²⁵I-labeled ([¹²⁵I]) human CT, with increasing concentrations of the plasma menbrane protein from 4.6-80 μg/ml, in a both time and temperature dependent manner. Specific binding of [¹²⁵I] human CT was competitively inhibited by concentrations of unlabeled homologous hormone more than 0.05 nM. Half-maximal inhibition of specific binding was observed with 0.5 nM human CT. Scatchard analysis of the data suggested the presence of one class of binding site with an apparent affinity constant of 4.08 × 10⁹M^-1. The binding of human CT was highly specific ; half-maximal inhibition of binding was observed with 100 nM synthetic [Asu^{1, 7}] eel CT, ACTH having no effect in this system. These results demonstrate that specific binding receptor sites for CT are present in the plasma membrane of rat liver, compatible with the CT function in these cells.

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The family history of diabetes in parents and siblings was analyzed in relation to the age of onset and previous obesity in patients with non-insulindependent diabetes mellitus (NIDDM). The frequency of a positive family history of diabetes in parents was higher in patients with the onset of diabetes earlier than 40 years of age than in those who developed diabetes after 50 years of age (32% vs 12%, p<0.001). The frequency of a positive family history in siblings was about 20% and fairly constant in patients who became diabetic after 30 years. The prevalence of diabetes in siblings was higher in patients with diabetic parents than in those without diabetic parents (p<0.001). The higher frequency of diabetes in parents of young-onset patients remained significant even in a comparison of patient groups of similar ages (50-59 years) at the interview. Patients with definite obesity in the past had a significantly lower frequency of family history of diabetes in parents (p<0.001), and a lower prevalence of diabetes in their parents (p<0.001) and siblings (p<0.05) than did patients without obesity. The frequency of patients who had diabetic siblings did not differ between obese and lean groups. These data suggest that implications of the presence of diabetes in parents and in siblings are different in family history studies. The higher frequency of a family history of diabetes in parents of young-onset and non-obese NIDDM patients may mean that exogenous diabetogenic factors such as obesity and aging are less important in the occurrence of diabetes in those who have diabetic parents than in those without diabetic parents.

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Synthetic human pancreatic growth hormone releasing factor (pGRF) was administrated intravenously to 14 acromegalic patients, and the response of plasma GH to pGRF was compared with that to TRH, GnRH or other GHstimulating agents in these patients. Three patients hyperresponded (more than 8 times), 4 patients responded (2-4 times), 4 patients hyporesponded (1.5-2.0 times) and 3 patients did not respond at all. There was no correlation between the responses to TRH and pGRF, however, an intimate relationship was observed between responses to pGRF and GnRH in the patients who hyperresponded to pGRF. A patient not responding to pGRF showed a marked response to insulin or clonidine and another patient not responding to insulin or clonidine did respond to pGRF. Similarly, some patients not responding to FK 33-824, a met-enkephalin analog, or arginine did respond to pGRF.

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Changes in the concentrations of progesterone, 17β-estradiol and 13, 14-dihydro-15-oxo-prostaglandin F2α(PGFM) were evaluated in the peripheral plasma of rabbits during late pregnancy by treating trilostane, an inhibitor of 3β-hydroxysteroid dehydrogenase, in an attempt to obtain further insight into the involvement of progesterone and prostaglandin (PG) in the initiation of parturition. The concentrations of progesterone were 18.8±2.2 ng/ml (mean±SE, n=6) before administration of the inhibitor, significantly (p<0.05) fell to 7.6±1.0 ng/ml (n=6) at 30 min, and remained low until 10 h after the drug administration. The concentrations of progesterone were still low (5.4±0.5 ng/ml, n=6) at 20-24 h after administration of the inhibitor, and were also low (4.9±2.2ng/ml, n=6) at delivery. Premature deliveries occurred at 28.8±2.0h after injection of trilostane (on days 29 of gestation). Increased concentrations of PGFM were observed at delivery. However, administration of trilostane induced no discernible changes in the concentration of estradiol. These findings suggest that delivery is induced by progesterone withdrawal and that synthesis prostaglandin F2α is remarkably increased at delivery in the rabbit.

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In a significant proportion of patients with acromegaly, a non-specific increase in plasma growth hormone (GH) has been recognized following administration of thyrotropin-releasing hormone (TRH) or luteinizing hormonereleasing hormone (LH-RH), probably due to the lack of the specificity of the receptor in their tumor cells. In this study, the effects of corticotropin-releasing factor (CRF), a newly isolated hypothalamic hormone, in addition to TRH and LH-RH, on plasma levels of GH and the other anterior pituitary hormones were evaluated in 6 patients with acromegaly. Synthetic ovine CRF (1.0μg/kg), TRH (500μg) or LH-RH (100μg) was given as an iv bolus injection, in the morning after an overnight fast. Blood specimens were taken before and after injection at intervals up to 120 min, and plasma GH, adrenocorticotropin (ACTH), thyrotropin, prolactin, luteinizing hormone, follicle-stimulating hormone and cortisol were assayed by radioimmunoassays. A non-specific rise in plasma GH was demonstrated following injection of TRH and LH-RH, in 5 of 6 and 2 of 5 patients, respectively. In all subjects, rapid rises were observed in both plasma ACTH (34.3±6.2μg/ml at 0 min to 79.5±9.5μg/ml at 30 min, mean±SEM) and cortisol level (9.1±1.3μg/dl at 0 min to 23.4±1.2μ/dl at 90 min). However, plasma levels of GH and the other anterior pituitary hormones did not change significantly after CRF injection. These results indicate that CRF specifically stimulates ACTH secretion and any nonspecific response of GH to CRF appears to be an infrequent phenomenon in this disorder.

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A 16-year old girl of short stature, with round face, mental retardation, and Albright's dimple sign was admitted for evaluation of hypocalcemia. Her serum calcium levels were 6.3-8.0mg/dl, and phosphorus 6.9-7.8 mg/dl. Although a diagnosis of pseudohypoparathyroidism was initially suggested, her serum iPTH concentration was low (0.1 ng/ml). Furthermore, an injection of synthetic human parathyroid hormone (100 U, hPTH (1-34)) was followed by a marked increase in urinary excretion of cyclic AMP and phosphorus. This case suggests that a shortened metacarpal is not a reliable guide in distinguishing between idiopathic hypoparathyroidism and pseudohypoparathyroidism and that a standard Ellsworth-Howard test is a prerequisite to differential diagnosis.

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TSH-receptor antibody (TRAb) activity and LATS activity of Graves' sera were compared. All of 50 LATS-positive cases were TRAb positive, although only 63% of LATS-negative cases were TRAb positive.
Binding of ¹²⁵I-TSH to the TSH receptors was inhibited dose-dependently by LATS-immunoglobulin. However, no correlation between TRAb activity and LATS activity was observed.
TRAb was positive in 2 LATS-positive cases even when the symptoms of hyperthyroidism were controlled by treatment (antithyroid or radioisotope). The positive TRAb was not changed in 4 Graves' disease patients whose LATS activity had disappeared following antithyroid treatment. These clinical studies show that TRAb is more sensitive than LATS and suggest that LATS may be one of a heterogenous population of antibodies to the TSH receptor in Graves' disease.

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The frequencies of HLA-antigens in A, B, C and DR loci were examined in 34 Japanese patients with acromegaly. The frequency of DRW9 was slightly higher and the frequency of DR4 was slightly, but not significantly, lower than the controls.

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