Human chorionic gonadotropin stimulation of relaxin secretion by luteinized human granulosa cells.

OBJECTIVE

To determine the effect of human chorionic gonadotropin (hCG) on relaxin secretion by long-term cultures of luteinized human granulosa cells (GC).

DESIGN

Luteinized human GC were collected from 10 women undergoing in vitro fertilization (IVF) cycles. Luteinized human GC from each woman were plated in replicate wells at 1 x 10(5) cells/well and exposed to medium 199 (GIBCO, Grand Island, NY), medium 199 with 1 IU/mL hCG, and/or medium 199 with 100 IU hCG/mL. Luteinized human GC were maintained for up to 40 days in culture. Spent media were changed every 2 days and assayed for relaxin and progesterone (P) at the conclusion of each experiment.

SETTING

Tertiary care center.

PATIENTS, PARTICIPANTS: Luteinized human GC were obtained from women undergoing controlled ovarian hyperstimulation for IVF with one of the following regimens: (1) clomiphene citrate with human menopausal gonadotropins (hMG); (2) hMG alone; or (3) hMG with leuprolide acetate. All women were less than 40 years of age, in good health, and were not taking medications other than those used in the ovulation-induction regimen.

MAIN OUTCOME MEASURES

Levels of P and relaxin in spent media.

RESULTS

Relaxin secretion by luteinized human GC was dependent on hCG stimulation and was detected only after a time lag in culture. After relaxin secretion was detected, it was maintained throughout the culture period (10 to 22 days). Luteinized human GC produced P immediately under both basal and stimulated conditions. Progesterone production continued throughout the culture period with hCG-stimulated cells producing significantly greater P after 4 to 8 days in culture.

CONCLUSIONS

Luteinized human GC obtained at the time of oocyte retrieval secrete relaxin in response to hCG stimulation and secrete P under both basal and hCG-stimulated conditions, thereby serving as a model to explore luteal function and control.