THE EFFECT OF PROLACTIN, HUMAN CHORIONIC-GONADOTROPIN, INSULIN AND INSULIN-LIKE GROWTH-FACTOR-I ON ADRENAL STEROIDOGENESIS IN ISOLATED GUINEA-PIG ADRENAL-CELLS

The controlling mechanism for adrenal androgen production has not been elucidated. The presence of receptors for prolactin, human chorionic gonadotropin (hCG), insulin and insulin-like growth factor 1 (IGF-1) in the adrenal cortex raises the possibility of their involvement in the control of adrenal steroidogenesis. This study was undertaken to investigate the effects of prolactin, hCG, insulin and IGF-1 in the presence and absence of ACTH on cortisol and androgen production using isolated guinea-pig adrenal cells. hCG 10(-7) and 10(-6) M significantly increased cortisol (P < 0.05) production. hCG 10(-6) M significantly increased androstenedione (A4) (P < 0.05) production. In the presence of ACTH, 10(-12) M, hCG 10(-6) M significantly increased the cortisol (P < 0.01) and A4 (P < 0.01) responses. Although the mean cortisol and A4 response to ACTH 10(-9) M was reduced in the presence of hCG 10(-6) M, this was not statistically significant. Prolactin 10(-8) M increased cortisol (P < 0.01), A4, and dehydroepiandrosterone (P < 0.05) production. In the presence of ACTH 10(-12) M, prolactin 10(-8) M increased the cortisol and A4 (P < 0.05) responses. However, the maximally ACTH-stimulated cortisol and A4 responses were not significantly altered in the presence of prolactin 10(-8) M. Insulin 10(-11)-10(-8) M and IGF-1 10(-10)-10(-7) M resulted in no significant increase in cortisol, A4 or dehydroepiandrosterone production. This study suggests that prolactin and hCG could play a role in modulation of adrenal steroidogenesis, particularly when ACTH levels are low. However, there was no evidence that prolactin or hCG is the specific cortical androgen stimulating hormone.