摘要:

In each of two experiments, groups of 7–10 adult male rats were injected once daily for 6 days with alkaline saline vehicle, 8 µg T3 or 16 µg T3. The rats in experiments 1 and 2 respectively, were 4.5 and 6.5 months old. The animals were bled by heart puncture and then autopsied on day 7. Treatment with T3 resulted in significant body weight losses and increased serum glucose levels but did not affect feed intake. Treatment tended to reduce testicular weights but did not affect pituitary levels of gonadotropins or serum levels of follicle-stimulating hormone. In experiment 1, ventral prostate weights were not affected by treatment but in experiment 2, seminal vesicle weights were increased by the high dose of T3. In experiment 1, serum levels of luteinizing hormone tended to be decreased by treatment and in experiment 2 the serum levels of luteinizing hormone were significantly reduced by the high dose of T3

ISSN:1663-2818    

DOI:10.1159/000178631

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

The glucose tolerance test (GTT) has been studied in thyroidectomized (T) rats 10 and 30 days after operation and in their age-paired controls. We have found that in normal growing animals the clearance rate of plasma glucose and the pancreatic insulin secretion to glucose stimulus were paralleled to increasing body weight. On the other hand, an impairment of the glucose tolerance was observed in T rats; this effect was more intense 30 days after the operation than 10 days after wards. On the other hand, the highest values of circulating insulin were significantly delayed, and pancreatic insulin secretion was also more intensely reduced when the hypothyroid condition was more fully developed. Very small daily doses of L-thyroxine (T4), 0.20 µg/10 g body weight for 10 days reinitiated growth, normalized the clearance rate of plasma glucose, and restored the glucose-induced pancreatic insulin secretion in thyroidectomized animals. Moreover, when T rats were treated with porcine growth hormone (GH) 100 µg/100 g body weight or with pituitary homogenates (Pt. H.), ½ pituitary/100 g body weight per day for 10 days, they showed a more normal patterns of pancreatic insulin release and glucose removal rate during the GTT. Our data suggest that the low clearance rate of plasma glucose and the diminished pancreatic insulin response to a physiological stimulus such as glucose in T rats might be related to impairment of the anterior pituitary function which accompanied it to the hypothyroid state. Furthermore, they point out that available levels of plasma GH are required for normal pancreatic insulin secreti

ISSN:1663-2818    

DOI:10.1159/000178632

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

The uptake of 3H-labelled glibomuride wasstudied in microdissected pancreatic islets of ob/ob-mice. The islets rapidly accumulated this insulin-releasing sulfonylurea derivative in amounts exceeding the sucrose space. Steady-state was reached within 5 min, suggesting that the drug was bound to the β-cell plasma membrane. The uptake of glibomuride was greater than that of tolbutamide but smaller than that of glibenclamide. It was significantly inhibited by serum albumin and, to a lesser extent, by glibenclamide. Tolbutamide as well as four analogues of tolbutamide and glibenclamide that lack blood-sugar-lowering capacity had no significant effect on the uptake of glibenclamide. It is suggested that the insulin-releasing potency of sulfonylureas depends on the magnitude of their binding to the β-cell plasma membran

ISSN:1663-2818    

DOI:10.1159/000178633

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Results are described giving prolactin plasma concentrations, as determined by radioimmunoassay, in 5 non-lactating female and 4 male calves from a few days after birth to an age of 20 or 24 months. The blood samples were always collected at the same time of day (8–9 a.m.). Prolactin concentrations were shown to be dependent on the season, higher values being found in the summer, lower values in the winter. A significant correlation (r = 0.9; p < 0.001) was found between prolactin levels and the number of daylight hours and temperatur

ISSN:1663-2818    

DOI:10.1159/000178634

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

The insulin-releasing activities of cyclic and non-cyclic nucleotides were studied with isolated pancreatic islets from obese-hyperglycemic mice. Substitution of cytidine, inosine, guanosine, or uridine for the adenosine moeity of cyclic 3’,5’-adenosine monophosphate was associated with a total loss of insulin-releasing ability. The 5’-nucleotide tri-phosphate derivatives of these nucleotides were all ineffective. It is suggested that cyclic AMP potentiation of glucose-stimulated insulin release in the mouse is highly specific for this nucle

ISSN:1663-2818    

DOI:10.1159/000178635

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

The urinary excretion of catecholamine acid metabolites, vanylmandelic acid (VMA) and homovanillic acid (HVA), in adrenalectomized and hypophysectomized rats was determined. The two above manipulations resulted in markedly increased excretion of both VMA and HVA in 24-hour urine samples and demonstrated high statistical significance from control rats. The increases were more profound after adrenalectomy. The administration of 5 mg of hydrocortisone daily to adrenalectomized rats produced gradual declines in VMA excretion after 3rd, 6th and 10th. After the 10th injection of hydrocortisone, the VMA excretion in the adrenalectomized rats was statistically insignificant from control rats. The administration of 4 IU of ACTH or 5 mg of hydrocortisone to hypophysectomized rats also returned the increased excretion of VMA to normal level. The HVA excretion followed similar pattern as VMA. After hypophysectomy and adrenalectomy urinary HVA increased significantly from control rats. The daily administration of hydrocortisone or ACTH, respectively, to adrenalectomized or hypophysectomized rats produced marked declines in HVA excretion. The results suggest that adrenal glucocorticoids serve as an inhibitory factor for catecholamine metabolite formation in normal rats. The absence of glucocorticoids is followed by increased levels of VMA and HVA.

ISSN:1663-2818    

DOI:10.1159/000178636

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Plasma adrenaline and noradrenaline in rabbits on the 30th day of pregnancy show significant increases. On the 31st day of pregnancy a sharp decline in plasma noradrenaline was observed, but adrenaline was higher than the controls. Adrenaline in plasma returned to control level at parturition, and no change occurred 4 h after parturition. Plasma noradrenaline was insignificant from controls at parturition but an increase was observed 4 h post partum. The determination of adrenaline stores of adrenals during pregnancy showed marked decrease at 30 days. This decrease continued up to 31 days. At parturition the adrenal adrenaline was higher than at 31 days. The ratios adrenaline to adrenaline + noradrenaline show increased sympathetic activity during the last part of pregnancy. The results suggest that variations in hormonal concentrations during the last part of pregnancy induce higher activation of the sympathetic nervous system which results in higher release of adrenaline and noradrenaline from the adrenals.

ISSN:1663-2818    

DOI:10.1159/000178637

出版商:S. Karger AG    

年代:1974

数据来源: Karger

ISSN:1663-2818    

DOI:10.1159/000178638

出版商:S. Karger AG    

年代:1974

数据来源: Karger