Studies were carried out to compare the 5' deiodination reactions of thyroxine (T₄) and 3, 3', 5'-triiodothyronine (rT₃) in rat liver and kidney homogenates. The 5'-deiodinase activity was assayed by the 3, 5, 3'-triiodothyronine (T₃) produced from T4 or by the ¹²⁵I-iodide released from ¹²⁵I-rT₃. The two 5' deiodination reactions had similar ranges of optimal pH, incubation temperature, and apparent Km, T4 1.1 and rT₃ 1.3μM. However, the apparent Vmax values for T₄ and rT₃ deiodination reactions were 0.9 and 220 pmol/mg protein/min, respectively. Both reactions were stimulated by thiol reagent but only rT₃ deiodination showed complete thiol dependence. The inhibitory effect of 6-propy1-2-thiouracil (PTU) on the 5' deiodination of rT₃ was 50 times as great as that of T₄. Only the 5' deiodination of rT₃ was inhibited by low concentrations of calcium and magnesium. The 5' deiodination reactions in the liver and kidney tissues showed very similar substrate specificity. However, only the hepatic deiodinase activity was reduced to 60-65% of the control value after fasting, whereas the renal 5'-deiodinase activity was unaffected or even enhanced by fasting up to 72 hours. The results showed the existence of a diverse and complex 5' deiodination system in the rat tissues which is comprised of multiple similar but distinct 5'-deiodinase enzymes with respect to their substrate specificity, tissue specificity and regulation.

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Enzymatic and histological features of muscular disorders associated with primary aldosteronism and glycyrrhizine-induced pseudoaldosteronism were studied. Among 10 patients with primary aldosteronism and 3 patients with pseudoaldosteronism, 5 patients were admitted to our hospital because of muscular weakness. The serum potassium (K) level was 1.86±0.21mEq/l in a myopathy group on admission, a value significantly less than that of the 2.74±0.10mEq/l in a non-myopathy group (p<0.01). Serum creatine phosphokinase (CPK), glutamate-oxyloacetate transaminase (GOT), and lactate dehydrogenase (LDH) were increased in the myopathy group compared to the non-myopathy group; serum CPK was 1412.6±902.6 vs. 22.8-1: 5.0mU/ml, serum GOT was 186.4±75.3 vs. 24.2±5.4mU/ml (p<0.05), and serum LDH was 1133.4±377.3 vs. 387.6±42.5mU/ml (p<0.05) in the groups with and without myopathy. Analysis of CPK isozymes revealed that the MM type exceeded 95%. The elevated serum CPK, GOT and LDH rapidly decreased to the normal range and muscular strength completely improved within 6 to 13 days after hospitalization, when the serum K level remained below than normal. Light microscopic finding of damaged muscle showed the diffuse necrosis and vacuolization of muscle fibers. Electron microscopic study clearly demonstrated complete dissolution of myofilaments with disappearance of sarcoplasmic reticulum and T-tubules in the necrotic muscle fibers. These results indicate that muscular lesions may occur in primary aldosteronism and pseudoaldosteronism when the serum K level is decreased to below 2.0mEq/l. This myopathy is not periodic paralysis but hypokalemic myopathy. The mechanism by which K deficiency causes muscular damage remains unknown.

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A highly sensitive assay for angiotensin I converting enzyme has been developed by using angiotensin I as a substrate. Angiotensin II generated in the reaction mixture was measured by a newly developed specific radioimmunoassay. To protect against angiotensin II destruction, bestatin, an inhibitor of angiotensinases, was added to the reaction mixture. Pepstatin, an inhibitor of renin, was also used to inhibit plasma renin activity. The reaction was stopped by adding EDTA and MK-521, inhibitors of angiotensin I converting enzyme. The specificity of the antiserum used for the angiotensin II radioimmunoassay was very high. The cross reactivity with angiotensin I was less than 0.5% and none of the proteolytic enzyme inhibitors crossreacted in the assay. The inhibitory effect of pepstatin on plasma renin activity was very high (more than 80%) under the standard assay conditions employed. Serum angiotensinase activity was completely inhibited by the addition of bestatin. An excellent correlation was obtained between this new method and the spectrophotometric method using a synthetic substrate, Hip-His-Leu. The generation of as little as 12pM of Angiotensin II can be detected. Such low concentration have not been measurable with the usual spectrophotometric method. This new method will facilitate clinical and experimental studies on this unique enzyme, since very low levels of activity can be determined by this highly sensitive radioimmunoassay for angiotensin II.

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To evaluate the PRL secretory mechanism in patients wtih PRL-secreting adenoma (PRL-oma), plasma PRL responses to dopamine (DA) were studied in these cases and in normal subjects. Plasma PRL values showed clear decreases during the infusion of DA (5μg/kg/min for 90 min) in both 6 normal and 7 PRL-oma subjects (%decrease: 43.8±3.9% vs. 53.9±5.6%; NS) and postinhibitory increases after the termination. However, the postinhibitory increase occurred more promptly and markedly in PRL-oma patients than in normal subjects, i.e. the postinhibitory increase exceeded the basal level 45 min after the termination of DA infusion in PRL-oma patients, whereas the increase in normal subjects did not exceed the basal level even 90min after the infusion. When domperidone was injected at the termination of DA infusion, the postinhibitory increases were significantly enhanced in either PRL-oma or normal subjects. The maximal increments in plasma PRL in the combination test of DA plus domperidone were significantly larger in PRL-oma patients, but were almost the same in normal controls, compared to the single domperidone test. In contrast, TRH did not modify the postinhibitory rises in 9 PRL-oma patients. These results indicate that the secretory properties and the sensitivities of lactotrophs to decreasing action of DA might be different between PRL-oma patients and normal controls. Further, the postinhibitory rebound phenomenon in PRL-oma patients is possibly determined by an overshoot of PRL storage concomitantly with a decreasing DA action. The PRL secretory properties of lactotrophs and the hypothalamic DA might play important roles in the postinhibitory increases in PRL secretion in patients with PRL-oma.

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PK (15), a homogeneous epithelial cell line from porcine kidney which was originally established through single cell cloning from PK-2a, was found to respond to [Asu^{1, 7}] eel calcitonin with an increase in adenosine 3': 5'-cyclic monophosphate (cAMP) content, but do not respond to parathyroid hormone or arginine vasopressin.
These cells were able to grow in a synthetic medium (a 1: 1 mixture of Dulbecco's modified Eagle's MEM and Ham's F12 medium) without any supplementary factor. The medium supplemented with selenous acid, transferrin, and insulin permitted a growth rate equivalent to those in serum containing medium. When grown in the serum-free defined medium, these cells showed an increase in cAMP content in response to [Asu^{1, 7}] eel calcitonin to approximately the same degree as in the serum containing medium (10% fetal calf serum). Our present study first indicates that PK (15) cells are capable of growing in the serum-free defined medium retaining the calcitonin responsiveness of the original cells.

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We studied the in vivo and in vitro effect of p-chlorophenoxyisobutyrate (CPIB) on insulin binding and glucose transport in isolated rat adipocytes. In the in vitro study, adipocytes were incubated with 1mM of CPIB for 2h at 37°C, pH 7.4, and then insulin binding (37°C, 60min) and 3-O-methylglucose transport (37°C, 2s) were measured. Incubation with CPIB did not affect either insulin binding or glucose transport in the cells. The addition of insulin (10ng/ml) with CPIB to the incubation media also did not affect the following insulin binding and glucose transport. In the in vivo study, rats were fed a high sucrose-diet containing 0.25% CPIB for 7 days. Serum cholesterol, plasma free fatty acid, and insulin levels were significantly decreased in the CPIB-treated rats. The treated rats demonstrated an almost 2 fold increased maximal binding capacity for insulin (189, 000 sites/cell for treated vs 123, 000 sites/cell for control cells). Basal glucose transport (glucose transport in the absence of insulin) significantly decreased in the CPIB-treated rats, although insulin-stimulated glucose transport was comparable in treated and control cells. Thus, CPIB might have no direct effect on glucose transport and insulin binding, as determined by the in vitro studies. Furthermore, a relatively shortterm in vivo treatment with CPIB, such as 7 days, did not stimulate glucose transport.

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A possible physiological role of prolactin (PRL) in human milk was studied. The concentrations of milk PRL were 36.5±5.8ng/ml on the first day after delivery and increased rapidly on the second day. Higher levels continued up to the fifth day. The levels of milk PRL showed no significant correlation with milk yield. Milk PRL was capable of binding to its receptors, suggesting its biological activities. In conclusion, human milk contains significant amounts of immunoreactive PRL. Milk PRL appears to be biologically potent, which raises the possibility that it may have certain physiological significance for the newborn.

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To examine the sensitivity to epinephrine in patients with anorexia nervosa, 20-60μg/kg body weight/min of epinephrine was infused for 30min each in 5 patients and 5 controls. The increase in pulse rate and the decrease in diastolic blood pressure were significantly smaller in the patient group. Elevated plasma GH levels in the patients were markedly suppressed by epinephrine infusion. These results indicate the β-adrenergic function is decreased at least in the cardiovascular system in patients with anorexia nervosa.

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A 52-year-old man with an acromegalic appearance of prolonged duration suffered abdominal colic attacks and hematuria during the middle of the course of the disease. The patient was diagnosed as having urolithiasis caused by increased urinary calcium. The calcium metabolic disorder was not considered to be due to hyperparathyroidism because serum calcium and PTH levels were within the normal range and no abnormality was observed in a parathyroidal scintigraph. The serum 1, 25-dihydroxyvitamin D (1, 25-(OH) 2D) levels (55.0 and 73.0pg/ml) were higher than the normal range (27.2-53.8pg/ml). A selective adenomectomy by the transsphenoidal route (Hardy's method) was performed, resulting in an improvement in the hypercalciuria and urolithiasis, and a decrease in the levels of serum 1, 25-(OH) 2D (23.0 and 23.0pg/ml). These findings suggest that GH may promote the activation of vitamin D in the kidney in acromegaly, resulting in an acceleration of calcium absorption in the intestine through the action of activated vitamin D and the induction of increased urinary calcium excretion by the urinary excretion of excessive blood calcium.

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On reviewing the preoperative clinical and laboratory findings and the surgical response seen in our series of 32 patients with renal hyperparathyroidism, the indication for parathyroidectomy was reevaluated. During the 5-year period from 1975 to 1979, parathyroid resection was performed in 9 patients who had various conditions for which surgery had been thought indicated. During the following period from January 1980 to March 1985, parathyroidectomy was carried out on 23 patients all of whom had roentgenologic evidence of generalized fibrous osteitis except for two whose indication for surgery was an elevation of the serum alkaline phosphatase level more than 45 KA units. The resected parathyroid glands had increased to 1 g or more in total weight in all the 25 patients who showed distinct postoperative improvement.
Laboratory evidence indicating the presence of generalized fibrous osteitis, such as subperiosteal resorption on phalanx roentgenograms and high serum alkaline phosphatase level, along with marked elevation of the plasma immunoreactive parathyroid hormone level, proved to be a good indicator for medically uncontrollable secondary hyperparathyroidism. Fracture, heterotopic calcification, pruritus or persistent hypercalcemia was not a parameter of severe hyperparathyroidism warranting parathyroid resection, unless there was concomitant evidence of fibrous osteitis. The preoperative use of the recently developed noninvasive techniques for parathyroid localization also proved to be useful in detecting the parathyroid glands large enough to fulfill the requirments for parathyroidectomy.

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In order to investigate the significance of oxytocin in pregnancy and labor, oxytocin concentrations in plasma and cerebrospinal fluid (CSF) were determined using the specific radioimmunoassay. Plasma and CSF samples were obtained from 23 pregnant women (11 pre labor, 12 in labor), 15 nonpregnant women and 4 men at spinal puncture for anesthesia.
In males and nongravidas, CSF levels of oxytocin were significantly higher than plasma levels. Plasma levels in pregnant patients pre or in labor were significantly higher than those in nongravidas. No significant difference between CSF levels in prelabor gravidas (mean±SE, 9.7±1.5μu/ml) and nongravidas (10.1±1.2μu/ml) was found. However, CSF levels in gravidas in labor (18.6±2.3μu/ml) were significantly higher than the levels in prelabor gravidas.
These results strongly suggest that oxytocin levels in human plasma and CSF are controlled by different mechanisms and that the increased oxytocin could have some specific central actions.

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Detailed oro-maxillofacial studies using dental casts, pantomograms and cephalograms were performed in 28 patients with Turner's syndrome and compared statistically to the results from 23 normal short children. Small tooth crown size, short tooth roots and advanced dental age were characteristic of patients with Turner's syndrome. However, the incidence of peg shaped teeth, malocclusion, high arched palate and congenital anodontia were not characteristic of patients with Turner's syndrome. The coronal arch width (C. A. W.) and basal arch width (B. A. W.) were greater and the coronal arch length (C. A. L.) and basal arch length (B. A. L.) were less in patient's with Turner's syndrome. These data indicate underdevelopment of the maxilla in the forward direction forming the wide-, flat-shaped facial characteristic of patients with Turner's syndrome.

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Somatomedin (SM) activity, GH, T₃ and T₄ were investigated in 6 girls with anorexia nervosa during hospitalization and at outpatient clinic. On admission, serum T₃ (27-62ng/dl) and SM activity (0.24-0.55U/ml) were low in all cases, while basal GH was extremely high in 2 cases. A significant negative correlation was found between SM activity and basal GH during the course of treatment (r=-0.61, p<0.02). The change in SM activity was related to that of the serum T₃ level and a significant positive correlation was found between SM activity and serum T3 (r=0.80, p<0.001).
These data suggest that decieased SM activity may suppress the inhibitory effect of SM on GH release and may raise the basal GH level. SM activity is one of the indicators of the nutritional condition in anorexia nervosa as well as the serum T₃ concentration.

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To evaluate the clinical significance of human growth hormone (HGH) dynamics during transsphenoidal microsurgery for acromegaly, serial HGH levels during the surgery were compared with the post-operative basal HGH levels in 15 acromegalic patients, retrospectively.
In all patients, in whom the HGH level immediately after tumor resection was reduced below 5ng/ml or the decreasing rate which stood for the magnitude of decrease of HGH during resection procedure was above 80%, postoperative permanent HGH levels fell to below 5ng/ml, namely, within the normal range.
The rapid radioimmunoassay (RIA) of HGH was developed by the use of high affinity antibody in order to inform the surgeons of plasma HGH levels quickly during the surgery. It is now possible to know HGH levels about 1 hour after submitting the samples. It was verified that HGH levels measured in the rapid RIA correlated well with those obtained in the conventional way. The rapid RIA method was applied to 6 patients and the correlation between HGH levels during the surgery and post operative levels was also studied prospectively. The results were essentially identical to those in a retrospective study.
It was suggested that the HGH level immediately after tumor resection and the extent of the decrease in HGH during the resection procedure were good indicators of the prognosis of surgical results in acromegaly and the rapid RIA method was useful in order to judge HGH levels quickly during the surgery.

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We have produced two antisera (R-1 & R-2) to human growth hormonereleasing factor (GRF)[1-44] NH₂. Both antisera can be used for human GRF radioimmunoassay (RIA) at a final dilution of 1: 50000. The antiserum R-2 was specific for the C-terminal amidated sequence of human GRF-44 and selectively recognized GRF [1-44] NH₂ but not GRF [1-44] OH or GRF [1-40] OH. The antiserum R-1 also significantly bound ₁₂₅I-rat GRF [1-43] OH at a final dilution of 1: 5000 and enabled us to establish RIA for rat GRF. In both RIA systems, intra- and inter- assay coefficients of variation at 50% inhibition were 8 and 12%, respectively. A median effective dose was 90-120 pg in human GRF RIA and 250-300 pg in rat GRF RIA. Utilizing the RIA, we demonstrated that the hypothalamic GRF content in rats which received monosodium glutamate during the neonatal period was less than 20% of that of controls. However, the hypothalamic GRF content was not altered in rats made hypothyroid by methimazole administration, another condition known to greatly impair GH secretion. An iv administration of the antiserum R-1 significantly suppressed GH release following the injection of antisomatostatin serum. Thus, these antisera can be a useful tool in examining the physiological and/or pathophysiological roles of GRF in human and rat.

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The change in, the amount of immunoreactive oxytocin in human term placental tissue due to cycloheximide, an inhibitory agent of protein biosynthesis, was observed by a tissue culture method.
The immunoreactive oxytocin content per gram tissue was 1.81ng/g and significantly decreased to 1.17-1.11ng/g when the concentrations of cycloheximide were at 1-10pg/ml in culture medium.
The total quantity of immunoreactive oxytocin including medium content was 1.82ng/g and significantly increased to 3.06ng/g in the control group. However, those of the groups in which added cycloheximide was at 1-10pg/ml, were 1.91-1.85ng/g and showed no remarkable changes after incubation.
The data suggest that immunoreactive placental oxytocin can be synthesized in the human placenta itself rather than in other tissues.

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Synthesized α-human atrial natriuretic peptide (α-hANP), at 10^-6M, failed to inhibit short-circuit current and basal and 10mU/ml vasopressin-stimulated osmotic water flow in the bladder either pretreated with cyclooxygenase inhibitor, or preincubated with arachidonic acid, a precursor of PGE₂. These results indicate α-hANP to have no direct effect on sodium transport and water permeability in the bladder, and no evidence was obtained indicating that α-hANP suppresses vasopressin-stimulated water flow by increasing PGE₂ production.

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Pituitary prolactin (PRL) responses to 4-day continuous infusion of thyrotropin- releasing hormone (TRH) and vasoactive intestinal polypeptide (VIP) were investigated in unanesthetized male rats using Alzet osmotic minipumps. The TRH dose infused was 3.6μg/day and the VIP dose was 32.8μg/day. Infusion of TRH with osmotic pumps elevated the plasma PRL level compared to controls over the 4-day infusion period. However, mean levels of PRL tended to decrease during the 4-day infusion. On the other hand, continuous VIP infusion elicited a significant continuous PRL release over the 4-day infusion period. Thus, it may be said that the PRL responses to infused TRH and VIP were maintained during the 4-day infusion.

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Changes in plasma glucose and insulin concentration in response to palatinose tingestion were compared with those to sucrose in eight normal volunteers. When 50 g of palatinose was administered, the plasma glucose gradually increased to its peak of 110.9±4.9mg/dl at 60 min after administration and maintained a plateau during the 120 min of the experiment. The peak value of plasma glucose to 50g sucrose in the same group was 143.3±8.8mg/dl at 30 min after administration and then the value sharply decreased to the fasting level. The cumulative increase in plasma glucose (ΣΔPG) to palatinose was significantly smaller than that to sucrose. The changes in the plasma insulin level almost paralleled those in the plasma glucose level. These results indicate that palatinose is more slowly absorbed than sucrose and therefore useful as a sweetener for diabetic patients.

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