Immunocytochemical localization of prolactin binding sites in mouse adrenal gland.

1. Prolactin (PRL) has been previously associated with adrenal secretion of either corticosterone, progesterone, or aldosterone. 2. PRL binding sites have been previously demonstrated in rat adrenal cellular membrane preparations. 3. No studies have reported specific zonal sites of PRL binding. 4. The current study demonstrates presence of both endogenously bound PRL and free receptor for PRL in zona fasciculata of mouse adrenal cortex. 5. This finding is consistent with a role for PRL in regulating adrenal secretion of either corticosterone or progesterone in the mouse.