Recombinant follicle-stimulating hormone stimulates ovarian androgen synthesis in down-regulated ovulatory women.

In order to study androgen secretion during controlled ovarian hyperstimulation for in-vitro fertilization-embryo transfer, an open randomized study comparing the response to recombinant or urinary follicle-stimulating hormone (FSH) in down-regulated cycles was performed. During FSH administration significant increases in testosterone, androstenedione and dehydroepiandrosterone sulfate (DHEAS) levels were observed. During the same period a slight decrease in luteinizing hormone (LH) levels was seen. At all times during the stimulation period a significant correlation between estradiol and testosterone or androstenedione levels was observed. We conclude that FSH, through granulosa derived paracrine factors, initiates thecal androgen synthesis and secretion.