Satoshi Hane

Evidence for a physiologic role of pancreatic glucagon in human glucose homeostasis: Studies with somatostatin☆

To study the role of glucagon in human glucose homeostasis, experimental glucagon deficiency was produced by infusing somatostatin (i. v. 250 mug bolus, followed by infusion of 500 mug/hr) in six normal subjects and in two hypophysectomized patients-an insulin-dependent diabetic and a nondiabetic. In normal subjects, somatostatin lowered plasma glucagon from a mean (plus or minus SE) basal level of 85 plus or minus 15 to 33 plus or minus 10 pg/ml, p smaller than 0.001. Concurrently, plasma glucose fell from 90 plus or minus 2 to 73 plus or minus 3 mg/100 ml, p smaller than 0.001. Serum insulin and growth hormone fell slightly during somatostatin infusion, while plasma free fatty acids rose. In both hypophysectomized patients, somatostatin lowered plasma glucagon and glucose levels. In all subjects, after stopping somatostatin infusions, plasma glucagon and glucose returned promptly to control values, while serum growth hormone did not change. In additional in vitro studies, somatostatin (1 mug/ml) had no effect on muscle glucose uptake. Since it is known that somatostatin has no direct effect on hepatic glucose production, these results suggest that the fall in plasma glucose during somatostatin infusion resulted from inhibition of glucagon secretion, thus providing evidence that this hormone plays a physiologic role in the maintenance of fasting euglycemia in man.

Effect of arginine on serum levels of insulin and growth hormone in obese subjects

Abstract After the infusion of argine, serum levels of immunoreactive human growth hormone increased only slightly in obese subjects, reaching a peak value at 60 minutes of 7.9 ± 2.5 ng./ml. (mean ± S.E.M.) vs. 28 ± 6 ng./ml. in normal subjects, in spite of comparable rises in serum levels of α-amino-nitrogen. In contrast, changes in serum levels of immunoreactive insulin were similar in both groups, with a peak value at 30 minutes of 144 ± 50 μU/ml. in obese and 145 ± 17 μU/ml. in normal subjects.

Enhancement of Arginine-induced Insulin Secretion in Man by Prior Administration of Glucose

Various sequential combinations of 20 gm. of glucose and 20 gm. of arginine were given as separate, twenty-minute infusions with a thirty-minute rest interval between infusions, to six nonobese, nondiabetic subjects. The sequence of glucose preceding arginine significantly enhanced the serum immunoreactive insulin response to this amino acid. Other sequences of glucose and arginine did not result in enhancement. The effect of a separate infusion of glucose preceding arginine was quantitatively similar to enhancement of insulin secretion by glucose (20 gm.) and arginine (20 gm.) infused simultaneously over twenty minutes. The response to arginine after glucose, however, resulted in earlier peak insulin levels than did the simultaneous glucose-arginine infusion. These results imply a difference in the insulin-releasing mechanisms of arginine and glucose. It is suggested that certain time-dependent reactions, as well as a prior elevation of blood glucose are required for the enhancing influence of glucose on arginine-induced insulin secretion.

Presence of ACTH in Pituitary Gland of Pacific Salmon (O. keta)

Summary Lyophilized pituitary tissue of the Pacific salmon (O. keta) and pituitary fractions, were examined for ACTH activity in hypophysectomized rats. The results indicate the presence of a component in the teleost pituitary gland capable of depleting the stores of adrenal ascorbic acid in the rat. In this respect the preparations are qualitatively identical with corticotropins (ACTH) of mammalian origin.

Adrenal Function During Long-Term Anesthesia in Man

Summary Plasma 11-OHCS were measured in 12 subjects during 7 hr of general anesthesia with endotracheal nitrous oxide (N2O) and halothane, and halothane alone. The 5 subjects who received the N2O-halothane anesthesia showed an early rise in plasma 11-OHCS, which corresponded to the duration of the excitation phase. After the short rise, the plasma 11-OHCS fell to hypoadrenal levels. The subjects who received halothane only (rapid induction of anesthesia) showed no rise in plasma 11-OHCS, but the 11-OHCS fell to hypoadrenal levels after induction. After 2 to 4.5 hr of general anesthesia, the plasma 11-OHCS rose spontaneously and remained elevated until the end of anesthesia. The sudden rise was not due to changes in feedback threshold and did not correlate with changes in concentration of the anesthetic. The urinary catecholamine secretion was not significantly altered during the anesthesia compared to a control period.

Gas chromatographic method for the determination of testosterone in urine

Abstract A method is described for measuring testosterone in the urine using glucuronidase hydrolysis, continuous extraction with methylene dichloride, and chromatography on silica gel column as well as thin-layer and gas chromatography. This method proved to be practical for processing large numbers of samples and gave consistently reproducible results in the more than 600 specimens tested in the course of clinical evaluation of patients.

Testicular testosterone response to human chorionic gonadotropin in the rat.

Summary The testicles from hypophysectomized rats respond to small doses of HCG, with the maximal concentration found at 45 min after injection of HCG. A method is reported for measuring testicular testosterone in the rat, using gas-liquid chromatography with a hydrogen flame ionization detector.