Synergism between granulosa and theca-interstitial cells in XXXX biosynthesis by gonadotropin-treated @entity35 ovaries: studies on the two-cell, two-gonadotropin hypothesis using steroid antisera.

@entity1 @entity172 @entity251 @entity1420 @entity1465 @entity342 @entity35
In @entity1 ovaries, luteinizing hormone (LH) induces @entity342 biosynthesis by theca interna cells, whereas both follicle-stimulating hormone (FSH) and LH stimulate aromatase activity by granulosa cells. The joint action of these two types of cell and pituitary hormones forms the basis of a 2-cell, 2-gonadotropin hypothesis for biosynthesis of @entity172 . We tested the synergism between these cell types using antisera against the @entity172 precursors @entity1420 and @entity251 . Ovaries were obtained from immature @entity35 two days after a single injection of pregnant mare serum gonadotropin (PMSG). Granulosa cells were obtained by puncturing the follicles, and ovarian remnants were dissociated with collagenase to derive cells from the theca interstitium. Granulosa and theca interstitial cells were cultured alone or in combination for 20 h. Granulosa cells secreted negligible amounts of @entity172 and @entity251 , but contained high aromatase activity. Treatment with both FSH and @entity1 @entity1465 increased production of @entity1420 in granulosa cells. In contrast, theca interstitial cells had negligible aromatase activity. Treatment with hCG, but not FSH, increased @entity342 production by theca interstitium; the hCG action was further augmented by the inclusion of exogenous @entity1420 . Furthermore, co-culture of gonadotropin-treated granulosa and theca interstitial cells resulted in substantial increases in @entity172 production, indicating synergism between the two types of cell. The increases in @entity172 production in the co-cultures were accompanied by decreases in @entity1420 content. To test the possibility that @entity1420 released by granulosa cells may serve as a substrate for production of @entity342 in theca cells, specific antiserum was used to adsorb @entity1420 present in the medium. Addition of the @entity1420 antibody inhibited gonadotropin-stimulated production of @entity251 (39% decrease) and @entity172 (64% decrease) by the combined cell cultures. The inhibitory effect on @entity172 production could be reversed by the addition of @entity1420 (10(-6) M) or @entity251 (10(-6) M) but not by the addition of a synthetic progestin, R5020. Since @entity251 released from theca cells may serve as the substrate for aromatases in granulosa cells, specific @entity251 antiserum was also used. Production of @entity172 by the combined cell cultures was inhibited (78%) by the @entity251 antiserum, but the inhibitory effect was completely reversed by exogenous @entity251 or @entity1420 . Thus, synergistic interactions between granulosa and theca interstitial cells are important in effecting maximal @entity172 biosynthesis.(ABSTRACT TRUNCATED AT 400 WORDS)
