摘要:

Normal 4-day cyclic rats were sacrificed at 10 a.m. and 3 p.m. on proestrus or estrus and at 10 a.m. on metestrus. Noradrenaline (NA), dopamine (DA) and tryptophan (T) concentrations varied only slightly. Serotonin (5-HT) concentrations showed characteristic changing patterns in many hypothalamic, limbic and midbrain structures with a decrease during proestrus and an increase during estrus being observed. Monoamine oxidase (MAO) activity changes were often parallel to the 5-HT changes, but were not as great. The marked changes in 5-HT early in proestrus are a further indication of its inhibitory effect on gonadotropin release mechanisms before the ‘critical period

ISSN:0028-3835    

DOI:10.1159/000122536

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Bilateral injections of 30 µg of 6-hydroxydopamine (6-OHDA, as base) into the anterolateral hypothalamic area induced constant vaginal cornification (CVC), poly-follicular ovaries and uterine hypertrophy in cyclic adult female rats. There were no important changes in the vaginal patterns or ovarian and uterine morphology in animals given injections in the same area with the solvent only and in animals given injections with 6-OHDA in the anterior amygdaloid area. It is suggested that the persistent estrus after anterolateral hypothalamic injections of 6-OHD A results from lesions of central catecholaminergic pathways, which are probably involved in gonadotropin secretion

ISSN:0028-3835    

DOI:10.1159/000122537

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Experiments were performed on dogs with hypothalamic lesions as well as on intact and hypophysectomized dogs. Adrenal venous blood samples were collected and analyzed for 17-hydroxycorticosteroids (17-OHCS). In intact dogs, a marked increase in adrenal 17-OHCS secretion was observed after an i.v. injection of histamine and following an i.v. infusion of cyanide. Adrenal 17-OHCS secretion in response to histamine was markedly reduced but not completely abolished by hypophysectomy and was partially impaired by anterior median eminence lesions and by posterior median eminence lesions, but was not significantly impaired by supramammillary lesions. Adrenal 17-OHCS secretion in response to cyanide was completely abolished by hypophysectomy, markedly reduced by posterior median eminence lesions and partially impaired by anterior median eminence lesions and by supramammillary lesions. Thus, a partial dissociation of the adrenocortical secretory responses to histamine and cyanide was observed in dogs with hypothalamic lesions, suggesting that the mechanism and the pathway to the anterior pituitary involved in the adrenocortical secretory response to histamine and cyanide are somewhat different.

ISSN:0028-3835    

DOI:10.1159/000122538

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

A morphological and ultrastructural study is described which indicates that cellular activity in the adenohypophysis correlates well with the circulating levels of corticosterone. Intense secretory activity is observed in all tropic cells of the adenohypophysis over 10 days; thereafter the cellular morphology shows a return to the control condition. There are, however, differences in the degree of adaptation between the different tropic cells. After its initial hyperactivity, corticotrope activity returned to a control level by 20 days. Thyrotrope activity was also found to adapt to control activity, but only after 40 days. Similar patterns were observed in the somatotrope and gonadotrope, where the initial hypertrophy returned to control levels by 20 days; thereafter, however, an inhibition was observed. The luteotrope however, seems to be an exception in that its level of activity increased throughout the duration of the stress procedure.

ISSN:0028-3835    

DOI:10.1159/000122539

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

The effect of unilateral ovariectomy on the protein-synthesizing activity of the hypothalamic arcuate and dorsomedial nucleus on both sides was studied in vivo as well as in vitro. Four weeks after the removal of 1 ovary, there was a significant increase in labelled amino acid incorporated into the arcuate neurons contralateral to the removed ovary as compared to those incorporated into the nerve cells of the nucleus on the ipsilateral side. In the dorsomedial nucleus, there was no difference between the 2 sides. On the basis of the present findings, the existence of a neural pathway between the ovary and the hypothalamic arcuate nucleus is assumed.

ISSN:0028-3835    

DOI:10.1159/000122540

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

The effect of fornix transection on plasma corticosterone and on midbrain (MID), septum/preoptic (S/POA) or hippocampal (HIP) tryptophan hydroxylase activity (THA) was studied in adult male rats. A mild stress resulted in higher levels of plasma corticosterone in operated as compared to sham-operated rats 6 and 40 h post-transection; however, at 30 days post-operation no difference was found. The response of THA to fornix transection was region-specific. No significant change in the S/POA region was found at any time. THA in the HIP, a terminal area of 5-HT fibers, showed a progressive fall over time to values 80% below normal levels. This result suggests that most of the 5-HT fibers to the HIP had been severed. A 28 h half-life for HIP THA was calculated. THA in the MID, an area known to contain the majority of 5-HT cell bodies with ascending fibers, was significantly reduced compared to sham controls at 6 h, 40 h, and 8 days post-transection. However, at 30 days post-operation no difference was found. The depression in MID THA by its rapid onset, the distance from the fornix transection site, and its return to normal after 30 days, is thought to be due to a transneuronal effect on the serotonin-containing neurons in MID raphe. The fall in MID THA at a time when plasma corticosterone levels are increased in fornix-transected rats may be compared with the situation in normal, stressed and adrenalectomized rats where MID THA and plasma corticosterone levels change in the same direction. The data suggest that the glucocorticoid effects on MID 5-HT-containing neurons are mediated transneuronally through the hormone concentrating cells in the HIP.

ISSN:0028-3835    

DOI:10.1159/000122541

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

In vivo specific nuclear binding of [2, 4, 6, 7 (n)-3H] estradiol (3H-E2), as indicated by diethylstilbestrol(DES)-blockable radioactivity, was measured 1 h after injection in adult intact male, untreated and testosterone propionate (TP)-pretreated or 5α-dihydrotestosterone (DHT)-pretreated gonadectomized (GDX) male and female rats. There was no sex difference in specific 3H-E2 binding in brain areas and anterior pituitary (PIT) of untreated GDX animals. DHT pretreatment had no effect on binding in any tissue. Specific nuclear binding in the preoptic area-anterior hypothalamus (POA-AH), median eminence-basal hypothalamus (ME-BH), amygdala (AMYG), septum (SEP), and dorsal hypothalamus (DH) was lower in intact males and TP-pretreated GDX males and females than in untreated GDX animals. Uptake in the PIT was not affected by TP pretreatment or by the presence of the testes, suggesting that the reduction in nuclear 3H-E2 binding observed in other tissues was caused by competition by estradiol formed in situ from TP or endogenous androgens for nuclear binding sites. Thus, the reduction in 3H-E2 uptake caused by the presence of TP or the testes could be used to estimate the degree of aromatization that occurred in these brain areas. In males, specific nuclear binding o

ISSN:0028-3835    

DOI:10.1159/000122542

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

12-day-old female and male pups were killed 10 min after the injection of either saline or thyrotropin releasing hormone (TRH), and plasma growth hormone (GH) and prolactin (PRL) levels were measured by radioimmunoassay (RIA). At all doses used (0.15, 0.3, 0.6 and 1.5 µg/100 g b.w.i.p.), TRH induced a significant, although not dose-related, increase in plasma GH levels, but was effective in releasing PRL only at the greatest dose level (1.5 µg/100 g b.w.). The GH-releasing effect of TRH was even more evident in 12-day-old pups subjected to central sympathectomy by 6-hydroxydopamine (6-OHDA, 60 µg/10 µl by intraventricular route) 1 week before; in these animals, TRH was ineffective in releasing PRL even at the greatest dose level (1.5 µg/100 g b.w.). In pups pretreated with 6-OHDA, the GH-lowering effect of insulin hypoglycemia or cold exposure was markedly reduced, while the PRL responses were unmodified. Baseline plasma PRL levels were markedly increased following 6-OHDA administration. It is proposed that in the infant rat, the greater GH than PRL responsiveness to TRH, which opposes the pattern of response present in the adult animal, may be due to the existence of a ‘physiologic’ functional disconnection between the central nervous system (CNS) and the anterior pituitary (AP). Results obtained following central sympathectomy by 6-OHDA, which further disrupted CNS-AP links, substantiate t

ISSN:0028-3835    

DOI:10.1159/000122543

出版商:S. Karger AG    

年代:1976

数据来源: Karger

ISSN:0028-3835    

DOI:10.1159/000122544

出版商:S. Karger AG    

年代:1976

数据来源: Karger

ISSN:0028-3835    

DOI:10.1159/000122545

出版商:S. Karger AG    

年代:1976

数据来源: Karger