AJP - Endocrinology and Metabolism, Vol 240, Issue 3 297-E301, Copyright © 1981 by American Physiological Society
Effect of 17 beta-estradiol on pituitary cAMP binding and responses to DBcAMP
L. K. Tang and F. Y. Tang
Effects of 17 beta-estradiol (E2) on adenosine 3',5'-cyclic monophosphate
(cAMP) binding and luteinizing hormone (LH) and prolactin (PRL) responses
to N6-O-2'-dibutyryl cAMP (DBcAMP) were examined in pituitary monolayer
cultures prepared from female rats. Incubation with 8 mM DBcAMP for 4 h
significantly (P less than 0.05) increased both LH and PRL release into
medium by two- to threefold. E2 pretreatment augmented the DBcAMP-induced
LH release but not PRL release to 160% of the non-E2-treated controls.
However, the cellular and total accumulation of both LH and PRL were
significantly increased in cultures pretreated with E2. The effect of E2
was time dependent, and the maximal effect was observed after 3 days of
treatment. Furthermore, E2 treatment significantly increased cAMP-binding
activities to 254% of the non-E2-treated controls. The time course of the
E2 effect on cAMP-binding activities closely resembled the time course of
the E2 effect on LH and PRL accumulation as well as the DBcAMP-induced LH
release. These results suggest that the priming effect of E2 on pituitary
LH and PRL responses to DBcAMP is associated with increased hormone
synthesis and cAMP binding stimulated by E2 pretreatment.
