Ovine Prolactin Potentiates the Action of Adrenocorticotropic Hormone on the Secretion of Dehydroepiandrosterone Sulfate and Dehydroepiandrosterone from Cultured Bovine Adrenal Cells

Summary

To determine the direct effect of prolactin on adrenal androgen secretion, the daily secretions of dehydroepiandrosterone sulfate (DHEA-S),dehydroepiandrosterone (DHEA), androstenedione and cortisol were determined in monolayer culture of bovine adrenal cells in the presence or absence of adrenocorticotropic hormone (ACTH) and/or prolactin. In the absence of ACTH ovine prolactin alone had no effect on steroid secretion during seven-day culture. Ovine prolactin, when administered in combination with ACTH, significantly potentiated the stimulatory effect of ACTH on DHEA-S and DHEA but not androstenedione secretion on the seventh day in culture. On the first day in culture prolactin showed no synergistic effect with ACTH on DHEA and DHEA-S secretion, although ACTH significantly increased DHEA and cortisol secretion. DHEA-S secretion increased as a function of prolactin concentration in the presence of ACTH. These results indicated that long-term treatment by ovine prolactin with ACTH caused the increase in adrenal androgen secretion from bovine adrenal cells. The site of action of prolactin was suggested to be the partial inhibition of adrenal 3β-hydroxysteroid dehydrogenase by the result of increases in DHEA-S and DHEA but not androstenedione secretion.

Key-Words:

Prolactin - Adrenocorticotropic Hormone - Dehydroepiandrosterone Sulfate - Dehydroepiandrosterone - Androstenedione