摘要:

In a sensitive animal model under the control of a dopaminergic-cholinergic balance, showing striking similarity to the extrapyramidal system, MIF did not possess dopaminergic or anticholinergic properties either with acute or chronic administration of the drug.

ISSN:0028-3835    

DOI:10.1159/000122661

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Somatic, endocrine and behavioral correlates of growth were measured in intact and hypophysectomized adult hamsters with or without electrolytic damage to the rostral septal area. Septal (SEP) lesions significantly increased somatic growth rate, food consumption and serum concentration of growth hormone (GH) and insulin. Pituitary GH content and concentration were reduced in lesioned hamsters. None of these changes were found in hypophysectomized hamsters with SEP lesions. SEP lesions did not affect the percentage of body fat. These data suggest that the septum or adjacent fibers of passage inhibit growth in adult hamsters.

ISSN:0028-3835    

DOI:10.1159/000122662

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Data that a substantial, transient release of gonadotropin-releasing hormone (GnRH) from the hypothalamus is a prerequisite for the serum luteinizing hormone (LH) surge are presented. Ovariectomized rats, in which daily afternoon LH peaks can be induced by estradiol benzoate (EB), were used as the experimental model. These rats present a homogenous, synchronized population having low hypothalamic stores of GnRH, thus facilitating detection of small physiological fluctuations in the levels of hypothalamic GnRH. Blockade, by Nembutal administration, of the serum LH surge on 2 consecutive afternoons results in elevated GnRH levels in the hypothalamus (1.79 ng in blocked rats vs 0.94 ng in controls). Abolition of LH secretion by administration of antiserum to GnRH, unlike the Nembutal blockade, does not affect GnRH levels. These results indicate that the afternoon LH surge is dependent on a transitory, enhanced release of GnRH from the hypothalamus, reflected by a depletion of GnRH stores.

ISSN:0028-3835    

DOI:10.1159/000122663

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Pharmacological and neurosurgical approaches were used to determine whether central serotoninergic systems are essential to the diurnal fluctuation of plasma corticosterone (B) and the enhanced secretion of ACTH induced by adrenalectomy. Normal and 3-week adrenalectomized (ADX) male rats were either acutely treated 24 h before sacrifice with parachlorophenylalanine methyl ester (PCPA, 250 mg/kg, i.p. injection), or were subjected to lesions of the nuclei centralis superior and raphe dorsalis, chief sites of serotonin(5-HT)-containing neurons. PCPA treatment produced a significant decrease in the 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) levels in the hypothalamus and dorsal hippocampus but did not abolish the plasma B rhythm. Lesions of the raphe nuclei did not abolish the diurnal rhythm of the steroid, either; they were followed, however, by a significant decrease in the 5-HT concentration of both brain structures, whereas no change was recorded in the noradrenergic (NE) level of either structure. Bilateral adrenalectomy induced a marked increase in the 5-HT concentration of the dorsal hippocampus. In the hypothalamus, the 5-HT level remained unaffected, whereas a slight increase in NE content was recorded. In ADX animals, raphe lesions significantly decreased the 5-HT concentration of the hypothalamus and dorsal hippocampus. No modification

ISSN:0028-3835    

DOI:10.1159/000122664

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The effect of intraspinal (i.s.) TRH administration on Prolactin (Prl) and thyrotropin stimulating hormone (TSH) serum levels was studied in order to verify the existence of a ventricular route in man for releasing factor delivery to the anterior pituitary, which has been previously reported in rats. Ten young male subjects were given 200 µg thyrotropin releasing hormone (TRH) i.s. injections and Prl and TSH were measured by radioimmunoassay (RIA) before and at various times after TRH administration. In the same subjects, an i.v. TRH test was also performed. After i.s. TRH, a prompt Prl increase (peak values at 10–30 min and return to baseline within 150 min) and a delayed increase (3–5 h following TRH injection) were observed in 7 and 5 subjects respectively, while an early elevation in serum TSH occurred in 6 subjects and a late one in other 6. In two subjects, a biphasic response of both tropins was present. Prl and TSH response to i.v. TRH was within the normal range in all cases; no late rise of the 2 hormones was observed. A kinetic experiment with 125I-TRH was also carried out to elucidate the mode of i.s. vs i.v. TRH action. These results confirm in man data reported in animals which suggest that TRH can be transported from the cerebrospinal fluid (CSF) to the portal system and the hypoph

ISSN:0028-3835    

DOI:10.1159/000122665

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The in vitro corticotropic releasing effects of vasopressin (VP) and hypothalamic median eminence (HME) extract were compared as a function of their concentration and preincubation and incubation times. Whereas HME extract augmented the ACTH secretion from non-preincubated adenohypophyses, VP released corticotropin from the pituitaries only after a 2 h preincubation period. The disappearance of endogenous VP during the preincubation time rendered the gland responsive. The maximal stimulation of ACTH secretion by VP was markedly less than that induced by HME extract. The results suggest the presence of VP receptor sites in the anterior pituitary (AP) which are probably different from the receptor sites of the hypothalamic corticotropin releasing factor (CRF).

ISSN:0028-3835    

DOI:10.1159/000122666

出版商:S. Karger AG    

年代:1977

数据来源: Karger