A superfusion system technique for the study of the sites of action of glucocorticoids in the rat hypothalamus-pituitary-adrenal system in vitro. II. Hypothalamus-pituitary cell-adrenal cell superfusion.
Basal and stimulated CRF release by hypothalamic blocks was studied by coupling the effluent of superfused hypothalamus tissue to a joint pituitary cell-adrenal cell superfusion system and measuring corticosterone production. Log dose-response curves of the adrenal cells for ACTH and of the pituitary cell-adrenal cell system for CRF were linear over the ranges used. Ca++-independent basal CRF release by the hypothalamus could be blocked in vitro by 0.2 mug/ml dexamethasone in the medium, or in vivo by treating the hypothalamus donor rats with corticosterone, 1 mg/rat ip 30 min before decapitation. These treatments did not impair CRF release caused by Veratridine (5 x 10(-6)M or by electrical stimulation. Adrenalectomy increased only basal but not stimulated CRF release. These results indicate that glucocorticoids have a hypothalamic site of action.
D000311:Adrenal Glands / Q000502:physiology*; D000315:Adrenalectomy; D000818:Animals; D003345:Corticosterone / Q000378:metabolism / Q000494:pharmacology; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D003366:Cosyntropin / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004558:Electric Stimulation; D005260:Female; D007031:Hypothalamus / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D008473:Median Eminence; D010477:Perfusion; D010902:Pituitary Gland / Q000502:physiology*; D051381:Rats; D014020:Tissue Extracts; D014701:Veratridine / Q000494:pharmacology
D014020:Tissue Extracts; D003366:Cosyntropin; D014701:Veratridine; D003907:Dexamethasone; D003346:Corticotropin-Releasing Hormone; D003345:Corticosterone