Regulation of steroid and steroid sulfate production and aromatase activity in cultured human granulosa-luteal cells

Abstract

The regulation of the production of steroids and steroid sulfates and the activity of aromatase in human luteinized granulosa cells were investigated. The cells were cultured for 48 h in the presence or absence of hCG and FSH. Basal production of pregnenolone (Pre, 0.3 ± 0.03 ng/μg protein) and progesterone (P 19.3 ± 17. ng/μg protein) were high compared with that of other steroids beyond P in the steroidogenic pathway. The concentration of 17α-hydroxyprogesterone (17-OHP) was lower 0.17 ± 0.06 ng/μg and that of other steroids in the 4-ene and 5-ene pathways and steroid sulfates <0.05 ng/μg. Both hCG and FSH (100 ng/ml) stimulated the production of Pre and P 3- to 5-fold, but only minimal stimulation of other steroids and steroid sulfates was observed. Aromatase activity of granulosa-luteal cells was measured from the rate of formation of 3H 2O from 1β-[ 3H]androstenedione (1β[ 3H]A) after exposing the cells to hCG, FSH or estradiol (E 2) for 48 h. Basal aromatase activity was relatively low, but hCG and FSH stimulated aromatase 8- and 4-fold, respectively. The incubation of granulosa-luteal cells with E 2 did not affect basal aromatase activity, but E 2 augmented FSH-stimulated aromatase 1.4-fold ( P < 0.025). The results suggest that there is low 17α-hydroxylase and steroid sulfokinase activity in human granulosa-luteal cells. Aromatase activity in these cells is regulated by both hCG and FSH, and intra-ovarian estrogens may regulate granulosa cell aromatase activity.