Glucocorticoid negative feedback and glucocorticoid receptors after hippocampectomy in rats

ANA M MAGARIÑOS; GUSTAVO M SOMOZA; ALEJANDRO DE NICOLA; GUSTAVO M SOMOZA

HORMONE AND METABOLIC RESEARCH

GEORG THIEME VERLAG KG

Año: 1987 vol. 19 p. 105 - 109

0018-5043

In rats with dorsal hippocampectomy, glucocorticoid receptors in the hypothalamus and anterior pituitary, as well as the pituitary transcortin-like compound, are preserved, in spite of a 60% depletion of glucocorticoid receptors in the hippocampus. In the hippocampectomized group, basal levels of serum corticosterone (CORT) were increased, although there was a normalresponse to ether stress. Inhibition of the response to ether with dexamethasone (DEX) was dose-dependent: whereas 100Mg/kg completely suppressed serum CORT, 10 Mg/kg were ineffective. However, we observed a reduced sensitivity to DEX inhibition with 25 fig/kg inhippocampectomized animals. These results indicate that the hippocampus is involved in negative feedback mechanisms, although different doses of DEX are needed for this demonstration. The inhibition of serum CORT due to 100 Mg/kg DEX suggests that negative feedback at sites other than the hippocampus was still operative, in agreement with normal levels of glucocorticoid receptors in the anterior pituitary and hypothalamus of hippocampectomized rats.