摘要:

We examined the role of vasopressin (VP) in brain-adrenal function by comparing the plasma corticosterone concentrations of rats genetically deficient in VP [Brattleboro rats, homozygous for diabetes insipidus (Dl-homo)] with those of control animals. Rats were subjected to stressful situations and exogenous ACTH, and their adrenal sensitivity to ACTH was assessed in vitro. Some Dl-homo rats were treated chronically with VP and their plasma corticosterone concentrations were examined during stress. We confirmed that Dl-homo rats have lower than normal plasma corticosterone concentrations during stress and this was at least partially due to adrenal glands relatively insensitive to ACTH.

ISSN:0028-3835    

DOI:10.1159/000122269

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Prolyl-leucylglycinamide (PLG) wasfound to augment the behavioral effects of DOPA and pargyline in mice and rats when administered orally. Behavioral studies in the DOPA test with repeated doses of PLG over 5 days did not reveal either cumulative or tolerance effects. Ablation of the pituitary, adrenals, ovaries, testes, pineal, spleen, thyroid, parathyroid, one kidney, or thymus did not disrupt this behavioral potentiation of DOPA by PLG. Furthermore, a neurochemical study in mice and rats did not show any significant increase in the content of dopamine, norepinephrine, or serotonin in the mouse brain. These studies suggest that PLG may have direct stimulatory effects on the mouse brain which do not require the presence of a number of somatic organs.

ISSN:0028-3835    

DOI:10.1159/000122270

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

A single subcutaneous injection of either 1.8 or5.4 µg lysine vasopressin (LVP) into parafascicular (pf) lesioned rats induced a dose-dependent preservation of a pole-jump shock avoidance response. The effect of the higher dose of LVP lasted for a minimum of 5 days whereas the effect of the lower dose was present for only 2 days. These results can be contrasted with the effect of 1.8 µg LVP in sham-operated rats in which the avoidance response is maintained for many days after injection. Daily subcutaneous administration of either 1 or 9 µg of the ACTH analogue (ACTH 4–10) to pf rats did not preserve the pole-jump response. However, in sham-operated animals, 1 or 3 µg ACTH 4–10 was effective in preserving the avoidance response in a dose-dependent way. Because ACTH 4–10 does not preserve avoidance behavior in pf-lesioned animals, the results of these experiments support the conclusion that the parafascicular area is essential for the behavioral effects of this peptide. In contrast, the fact that LVP is effective in lesioned animals (even though higher doses are required than are normally used), together with the earlier finding that local application of LVP in the posterior thalamic region results in a preservation of the avoidance response, indicates that LVP may have its site of action in the parafascicular area as well as in other brain s

ISSN:0028-3835    

DOI:10.1159/000122271

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Experiments were performed to examine the mechanism by which the stimulation of teats of heifers and cows leads to prolactin release. It was found that the height of the prolactin peaks is strictly dependent upon the number of teats stimulated. When the teats are stimulated at short intervals, a type of sensitization to the stimulus occurs. This response may be further enhanced if the degree of stimulus (i.e., the number of teats stimulated) is increased. Heifers responded significantly more intensely to stimulation of teats than cows did. The stimulation of teats induces only a slight prolactin release in bulls.

ISSN:0028-3835    

DOI:10.1159/000122272

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

The effect of small bilateral hypothalamic lesions on the rate of aldosterone production by adrenal glands from sodium-deficient rats was studied in vitro. Lesions located in the median eminence (ME) or in the ventromedial nucleus (NVM) reduced both aldosterone and total corticosteroid production (in vitro). Lesions in the nucleus paraventricularis (NPV), the nucleus supraopticus (NSO) or the supraopticoneurohypophysial tract (Tr.S.) caused a substantial decrease in the rate of aldosterone production. Treatment with growth hormone (GH) restored aldosterone production by the adrenals of rats with NPV-lesions but had no effect in rats with lesions of the Tr.S. In contrast, treatment with vasopressin failed to affect aldosterone production of rats with NPV-lesions but restored the rate of aldosterone production of rats with lesions of the Tr.S. The increased water intake which resulted from lesions of the Tr.S. was normalized by the administration of vasopressin in doses which also restored aldosterone production in these animals. It is concluded that the hypothalamus controls aldosterone production in the sodium-deficient rat through various pituitary hormones.

ISSN:0028-3835    

DOI:10.1159/000122273

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Light deprivation by blinding leads to involution of the reproductive organs and cessation of cyclic vaginal phenomena in adult fe-male hamsters. Associated with the atrophy of the reproductive system are elevated LH levels and depressed prolactin levels in the anterior pituitary gland. Chronic treatment (15 or 30 days) of blind hamsters with synthetic luteinizing hormone releasing factor (LRF) decreased pituitary levels and elevated plasma titers of LH. Neither pituitary nor plasma levels of prolactin were influenced by LRF treatment. Pinealectomy completely reversed the effects of blinding on the reproductive organs and on the pituitary levels of LH and prolactin.

ISSN:0028-3835    

DOI:10.1159/000122274

出版商:S. Karger AG    

年代:1974

数据来源: Karger