Corticotrophin-releasing factor and arginine vasopressin in the hypothalamo-hypophyseal portal blood of rats following high-dose glucocorticoid treatment and withdrawal.

Hypothalamo-hypophyseal portal blood was obtained from rats treated with chronic, high-dose prednisolone in the drinking water and after subsequent withdrawal of the steroid for up to 7 days. Corticotrophin-releasing factor (CRF) immunoreactivity in portal blood was reduced by treatment with prednisolone but not completely abolished. There was a rapid recovery of CRF to control values within 3 days of withdrawal of prednisolone. There was no significant change in arginine vasopressin (AVP) in portal blood over the time-course of the experiment.