摘要:

Oophorectomy accelerates the turnover of 3H-norepinephrine (3H-NE) in rat brain, but does not decrease endogenous brain norepinephrine content. If ovariectomized rats are treated with a given dose of (α-MPT), an inhibitor of norepinephrine synthesis, brain norepinephrine α-Methyl para-tyrosine levels do not fall to the same extent as in unoperated animals given the same dose of α-MPT, even though the turnover of brain 3H-NE continues to be accelerated. These data indicate that ovariectomy increases brain norepinephrine synthesis, and also decreases the sensitivity of rats to inhibitors of norepinephrine synthesis such as α-MPT. Ovariectomy or treatment with follicle-stimulating hormone (FSH) also increases the accumulation of 3H-catechols (predominantly 3H-NE) in rat brain, following the intraperitoneal administration of 3H-tyros

ISSN:0028-3835    

DOI:10.1159/000121947

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

In order to clarify a short- and auto-feedback control of FSH release from the anterior pituitary, changes in plasma and pituitary FSH and LH were investigated in rats with FSH implanted into the ME of the hypothalamus and into the anterior pituitary. FSH was bioassayed by the Igarashi-McCann method and LH by the ovarian ascorbic acid depletion method. The following results were obtained. 1. Stereotaxic implantation of FSH (NIH-FSH-ovine) into the ME of ovariectomized rats for 7 days significantly decreased plasma FSH levels in each of 3 experiments and significantly reduced pituitary FSH in 2 out of 3 experiments. Neither pituitary content nor plasma levels of LH showed any significant change in the same rats. 2. Stereotaxic implantation of FSH into the anterior pituitary for 7 days inovariectomized rats did not induce any constant change in plasma FSH levels, butsignificantly decreased pituitary FSH content in all 3 experiments. In 2 out of 3experiments, there was also a significant decrease in plasma LH levels. Pituitary LHcontent remained unchanged. 3. Stereotaxic implantation of FSH into the ME of intact adult female rats for 7 days significantly decreased both plasma and pituitary FSH, but the plasma and pituitary LH did not change significantly. 4. These results clearly demonstrate two different mechanisms of FSH secretion control: the short-feedback and the auto-feedback. The term ‘short-feedback control’ is used to characterize the ability of FSH to inhibit both FSH release and synthesis at the hypothalamic level, while the term ‘auto-feedback control’ is reserved to characterize the ability of FSH to inhibit its own synthesis at the anterior pituitar

ISSN:0028-3835    

DOI:10.1159/000121932

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The in vitro influence of dopamine on the in vitro incorporation of leucine-4,5-3H into rat pituitary gland prolactin and growth hormone was studied. This catecholamine primarily inhibited the release of newly synthesized prolactin from the pituitary gland, but had no effect on growth hormone production. Reserpine and perphenazine, agents that deplete catecholamine stores in the brain, greatly increased the synthesis and release of prolactin but not of growth hormone. Guanethidine, however, produced a slight inhibition in prolactin synthesis. The injection of iproniazid and pargyline, monoamine oxidase inhibitors, had only minimal effects on the in vitro incorporation of radioactive leucine into prolactin and growth hormone. The pituitary glands from rats bearing the prolactin- and growth hormone-secreting tumor MtTW5 synthesized significantly less prolactin than controls. Although no difference in catecholamine concentration was found in the hypothalamus of control and tumor-bearing rats, the injection of the latter group with reserpine or perphenazine restored prolactin to supernormal levels. These data suggest that catecholamines may have a physiological function to regulate prolactin synthesis and release in the rat pituitary gland.

ISSN:0028-3835    

DOI:10.1159/000121933

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The effect of acute treatment with perphenazine on the hypothalamic content of PIF was studied in adult male rats. PIF was measured in vivo by injecting hypothalamic extracts into the carotid artery of assay rats pretreated with perphenazine and pentobarbital sodium. PIF content in the hypothalami of rats 1 h after the injection of perphenazine was significantly higher than in control rats. This observation was interpreted as evidence that perphenazine produced accumulation of PIF in the hypothalamus, probably due to blockage of release of this factor from the hypothalamic neurons. The possibility of enhanced release of PRF is also discussed.

ISSN:0028-3835    

DOI:10.1159/000121934

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The mechanism of action of a new synthetic steroid, 6-dehydro-16-methylene-hydrocortisone (STC 407), which has been found useful in the treatment of Cushing’s syndrome due to adrenal hyperplasia, was studied in the rat. After treatment of normal rats with STC 407 for 11–14 days, the CRF content of the median eminence of the hypothalamus (SME), the concentration of ACTH in the anterior pituitary, the wet weight of the adrenal glands/ 100 g b.w., the adrenal corticosterone concentration/100 mg, and the plasma corticosterone level were significantly decreased. After treatment of adrenalectomized rats with STC 407 for 4 days, the concentration of ACTH in the pituitary was increased, but there was no appreciable change in CRF activity in the SME. Plasma levels of ACTH, which were elevated after adrenalectomy, decreased to undetectable levels after 4 days’ treatment with 400 µg/100 g b.w. daily. Treatment of adrenalectomized rats with this steroid for 13 days considerably reduced CRF activity in the SME, and significantly raised the pituitary ACTH content. These results indicate that STC 407 suppresses both the release and the synthesis of ACTH by the pituitary in normal rats, this effect being mediated at least in part by a reduction in hypothalamic CRF activity. In adrenalectomized rats, the predominant effect of this steroid seems to be suppression of release of ACTH by the pit

ISSN:0028-3835    

DOI:10.1159/000121935

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The action of some steroid drugs on aggressive behaviour was studied in mice and rats, using fighting isolated mice and muricide rats for this purpose. It was seen that hydrocortisone increased aggressiveness while hydroxydione decreased it, in both the above-mentioned tests. Desoxycorticosterone decreased the muricide reaction in rats, but failed to change the aggressive responses of isolated mice. In contrast, G-strophanthin decreased mice aggressiveness but exerted no effect on the rat muricide reaction. These findings are discussed in the context of the action of adrenal steroid hormones and other steroid drugs on various parts of the central nervous system.

ISSN:0028-3835    

DOI:10.1159/000121936

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Electrolytic lesions of three different sizes were placed in and around the ventromedial hypothalamic nuclei (VMN) in weanling rats. After three weeks, during which food intake was measured, the rats were killed and the following parameters were measured: plasma growth hormone (GH), insulin and glucose, carcass fat, water and lean body mass, pituitary weight and GH content, and ponderal and linear growth. Progressive decreases in pituitary weight, pituitary and plasma GH, linear growth, and carcass water and lean body mass were produced by increasing lesion size. Concomitant increases occurred in plasma insulin and carcass fat. Ponderal growth and plasma glucose were unaffected by any of the lesions and none of the experimental groups exhibited hyperphagia. The data indicate that the VMN are a control site for GH and insulin secretion. The lack of correlation between parameters of growth and those of obesity suggests that the two hormonal control mechanisms are subserved by independent neuronal assemblies.

ISSN:0028-3835    

DOI:10.1159/000121937

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Administration of purified porcine TRH to mice by intravenous subcutaneous, intraperitoneal, or intramuscular routes produced a significant release of TSH from the anterior pituitary gland. Subcutaneous administration of TRH in dilute acetic acid or 5% carboxymethylcellulose produced a prompt but somewhat smaller response at 2 h that increased between 2 and 4 h. Subcutaneous injections of TRH emulsified in glycerol and in sesame oil were associated with an approximately 30% decrease in response at 2 h as compared with intravenously administered TRH. TRH emulsified in Freund’s adjuvant and injected subcutaneously was associated with a 62% decrease in response at 2 h followed by marked increase at 4 h. It is suggested that Freund’s adjuvant, glycerol, and sesame oil slow the rate of absorption of TRH from the injection site. Plasma radioactivity levels, after the injection of tritiated TRH, correlate with the patterns of response seen when TRH is followed by bioassay using the same vehicle and mode of administrat

ISSN:0028-3835    

DOI:10.1159/000121938

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The acute effects of a single injection of perphenazine on pituitary and blood prolactin levels were studied in male rats and rabbits. Prolactin from both sources was determined by bioassay. A significant rise in blood prolactin became visible as early as 0.5 h after injection of perphenazine – earlier times were not studied – and remained high for at least 4 h. The prolactin peak following intravenous injection in rabbits was attained after 1 h, while in rats injected sub-cutaneously, it was reached after 2 h. Concomitantly, pituitary prolactin in rats decreased, falling to a minimum level within 2 h, and remaining low for at least 4 h. These results are interpreted as further evidence that perphenazine induces immediate release of prolactin from the pituitary into the blood. This release is probably due to suppression of the hypothalamic prolactin-inhibiting factor. The possibility that perphenazine promotes prolactin synthesis is also discus

ISSN:0028-3835    

DOI:10.1159/000121939

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The present study deals with the 5-HTPD activity in the rat pineal gland from birth up to the 20th day of life, as well as the effect of constant light or darkness from birth and of substrate administration on enzyme activity during this period. No activity was found on the first day of life. However, in 3-, 6-, and 10-day-old animals, the 5-HTPD activity corresponded to 1/12, 1/3, and ½, respectively, of the adult values. Enzymatic activity in the pineal gland of 6- and 10-day-old rats kept from birth under constant light conditions was significantly higher than in control animals kept under alternate 12-h periods of light and darkness. No modifications in the developmental pattern of 5-HTPD was observed under constant darkness conditions, or after the administration of substrate. 5-HT content increased 45 min after the application of 5-HTP, only in 20-day-old rats

ISSN:0028-3835    

DOI:10.1159/000121940

出版商:S. Karger AG    

年代:1970

数据来源: Karger