摘要:

To investigate the location of estrogen-responsive neurons active in feedback processes, the effect of hypothalamic deafferentation upon gonadotropin (GTH) secretion was measured both by the morphology of intrasplenic ovarian grafts in ovariectomized rats and by radioimmunoassay of their serum GTH levels. Either complete or anterolateral deafferentation was performed with the anterior position of the knife cut varied over a 2-mm range. After either cut, luteinization of intrasplenic ovarian grafts was correlated with the precise location of the rostral portion of the deafferentation. As long as the knife cuts were positioned so as to include the region of the suprachiasmatic nuclei (SC) within the de-afferented hypothalamus, intrasplenic grafts were fully luteinized and serum levels of LH were comparable to those of control ovariectomized animals. If the knife cuts excluded the SC area from the deafferented hypothalamus, intrasplenic ovaries were polyfollicular and LH levels were significantly lower than in the control group. FSH titers were elevated above reported levels for the intact diestrous rat in all groups even though the morphology of the ovarian grafts was different, and no significant inter-group differences in FSH were observed. These data are consistent with the localization of important estrogen-responsive neurons within the SC region. Uterine weight and FSH measurements suggest that intrasplenic ovaries may secrete systemically-active levels of steroids, although at titers insufficient to alter the vaginal epithelium.

ISSN:0028-3835    

DOI:10.1159/000122276

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

To test the possibility that the septum is essential forrhythmic pituitary-adrenal function, septal nuclei and fibers were re-moved by suction from adult female rats. Rhythmic pituitary-adrenal function was assessed by fluorometric measurement of non-stress plasma corticosterone in blood samples obtained at different times during the 24 h light-dark cycle. At 3 and 5 weeks after surgery, a.m. and p.m. non-stress plasma corticosterone levels were comparable in all groups, and all groups showed significant diurnal variations in steroid levels. Diurnal steroid patterns were studied in individual rats at 9 weeks after surgery by collecting 3 blood samples (0.5 ml) at 10 h intervals (07.00, 17.00, 03.00). Septal ablation, with concomitant interruption of fornix, was compatible with normal diurnal variations in plasma corticosterone concentrations. Lesioned rats demonstrated vaginal cycles and normal numbers of tubal ova at estrus. The data indicate that the diurnal pituitary-adrenal rhythm persists in the absence of septum and fornix and suggest that these structures are not essential for this rhythm.

ISSN:0028-3835    

DOI:10.1159/000122277

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Bilateral lesions produced with a platinum electrodewere placed in the anterior or central parts of the mediocortical amygdaloid nuclei, or in the anterior and basal region of the ventral hippocampus of 22-day-old female rats, and the effects on vaginal opening (VO), first puberal ovulation and subsequent vaginal cyclicity were recorded. Lesioning of the anterior part of the amygdaloid mediocortical nuclear complex resulted in precocious puberty, whereas lesions located in the central parts of these nuclei did not influence the onset of puberty. On the other hand, a significant delay of VO and the first ovulation was observed after bilateral hippocampal damage. The results suggest an inhibitory action of the anterior mediobasal amygdala on the prepuberal gonadotropin secretion and indicate a reciprocal relationship between the anterior amygdala and the ventral hippocampus in the control of female puberty.

ISSN:0028-3835    

DOI:10.1159/000122278

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Previous studies have indicated that septal ablation produces an exaggeration of adrenal activation in response to stress and have suggested further that the threshold for activation might be lowered. In order to examine the threshold for activation, rats lesioned in the septal area were subjected to various levels of electric shock, after which corticosterone and prolactin responses were examined. Although baseline corticosterone values were unaltered, plasma corticosterone concentrations in lesioned animals were elevated in response to stimuli that did not produce a corresponding elevation in sham-lesioned and unlesioned animals. Neither baseline nor stress levels of prolactin were affected by septal lesions at the times studied. It is concluded that a septal lesion lowers the stimulation threshold for activation of the pituitary adrenal axis and is suggested that corticosterone and prolactin stress responses are under different neural control.

ISSN:0028-3835    

DOI:10.1159/000122279

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Because of sleep alterations in schizophrenia, 4 schizophrenic patients were studied to evaluate sleep-associated GH release. The GH night pattern was studied for 2 consecutive nights using a continuous blood sampling procedure, with simultaneous EEG, EOG, and EMG scoring. Sleep-related GH secretion was impaired in 3 out of 4 patients. No close correlation was evident between EEG sleep stages and GH secretion. Finally, correlations between biogenic amine disturbances in schizophrenia and GH night release impairment are discussed.

ISSN:0028-3835    

DOI:10.1159/000122280

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

This study was aimed at determining whether 3-iodo-L-tyrosine (mono-iodotyrosine, MIT), a potent but short-lived inhibitor of tyrosine hydroxylase, is able to release prolactin secretion from dopamine inhibition. Administration of MIT (100 mg/kg, i.p.) to normal rats caused a highly significant elevation of serum prolactin levels within 30 min. This rise was not due to the initial metabolites of MIT. The properties of MIT suggest its use in clinical studies of prolactin secretion.

ISSN:0028-3835    

DOI:10.1159/000122281

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Intraperitoneal injections of alpha-methyl-para-tyrosine and reserpine had clear-cut second metamorphic effects, identical to those induced by prolactin, in the red eft (terrestrial stage) of the redspotted newt, Notophthalmus viridescens. Pentobarbital had less pronounced effects, and alpha-methyl-meta-tyrosine had no effect other than the darkening of the skin.

ISSN:0028-3835    

DOI:10.1159/000122282

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

To study the site of the gonadotropin-inhibitory action of estrogen, implants of crystalline estradiol benzoate were placed in the medial basal hypothalamus of spayed female rats. The implants depressed circulating luteinizing hormone (LH) levels, without decreasing the responsiveness of the pituitary to LH-releasing factor. Thus, estrogen can apparently suppress LH-controlling mechanisms in the brain, and the negative feedback effects of these intracerebral implants do not result from diffusion to the pituitary gland.

ISSN:0028-3835    

DOI:10.1159/000122283

出版商:S. Karger AG    

年代:1974

数据来源: Karger

ISSN:0028-3835    

DOI:10.1159/000122284

出版商:S. Karger AG    

年代:1974

数据来源: Karger

ISSN:0028-3835    

DOI:10.1159/000122285

出版商:S. Karger AG    

年代:1974

数据来源: Karger