Central modulation of immunoreactive arginine vasopressin and oxytocin secretion into the hypophysial-portal circulation by corticotropin-releasing factor.

Corticotropin-releasing factor (CRF), a potent ACTH secretagogue, has been found to exhibit many characteristics of central neurotransmitter/neuromodulatory substances. In this capacity, hypothalamic CRF might participate in postulated autoregulatory processes which regulate net secretion of adenohypophysical ACTH. We have examined the actions of centrally injected ovine CRF on the secretion of immunoreactive CRF, arginine vasopressin (AVP) and oxytocin (OT) into the hypophysial-portal circulation of urethane-anesthetized rats. Our observations do not support a short-term autoregulatory role for CRF. However, central administration of CRF was associated with a dose-dependent inhibition of hypophysial-portal concentrations of immunoreactive AVP and OT, suggesting potentially important central interactions among putative ACTH-regulatory factors.