[A study on cellular interaction between theca and granulosa cells in estradiol biosynthesis by the human ovary].

Cellular interaction in estradiol biosynthesis by two types of cells in the ovary has been suggested by previous studies. To verify this, steroidogenesis by theca and granulosa cells, separated or combined, was investigated using a two cell combined monolayer culture method. Granulosa and theca cells were harvested from preovulatory follicles of women with normal menstrual cycles. RIA measurements of steroidogenesis revealed the following: 1) Estradiol (E2) production by the combined culture after 24 h and 48 h was significantly higher than the total for each separated culture. 2) delta 4-androstenedione (delta 4) production by the combined culture after 24 h was significantly lower than total delta 4 production by each separated culture. 3) E2 production by the combined culture revealed higher values than the delta 4-added granulosa cell culture after 24 h. These data suggest that cellular interaction is of a synergistic character and it may be attributed not only to aromatase substrate (delta 4), but also to some intercellular E2 stimulating factor.