Modulation by dopamine and estradiol of the central effects of angiotensin II on anterior pituitary hormone release.

Abstract

The effects of iv or intraventricular (ivt) angiotensin II (All) administration on plasma levels of PRL, LH, GH, and TSH were studied in conscious ovariectomized (OVX) female rats with (and in some cases without) estradiol benzoate (Eb) priming. Both iv and ivt administration of AII increased LH levels in OVX, Eb-primed rats, but not in OVX, unprimed animals. Central All injection in OVX, Eb-primed rats induced sustained decreases in PRL and GH levels, which were reversed by pretreatment with saralasin, a specific AII receptor blocker. Systemic administration of AII in OVX, Eb-primed rats produced rapid and transient changes in PRL and GH levels. Peripheral dopaminergic receptor blockade with domperidone prevented the ivt AII-induced decline in PRL levels. Plasma levels of GH and LH were depressed after domperidone treatment, but ivt AII still induced a modest but significant decrement in GH levels. Plasma levels of TSH were not affected by either ivt or iv injection of AII Similarly, AII treatment in dom...