Bifunctional role of transforming XXXX -beta during granulosa cell development.

@entity268 @entity1420 @entity7813 @entity2140 @entity5987 @entity1810 @entity35 @entity4742 @entity1928
Regulatory actions of transforming @entity2140 -beta ( @entity1810 ) on granulosa cell function were analyzed in cells cultured from the ovaries of @entity4742 -implanted @entity35 . In the presence of a suboptimal concentration of FSH (5 ng/ml) that increased LH receptors by 100-fold during a 72-h culture, @entity1810 augmented this response in a dose-dependent manner with a maximal effect at 16 pM. In contrast, the @entity2140 inhibited the @entity7813 response to an optimal dose of FSH (50 ng) by up to 50% and was inactive in the absence of gonadotropin. @entity1810 also enhanced the formation of @entity268 by 5 ng FSH and partially inhibited the effects of higher FSH concentrations. However, the actions of @entity1810 were more prominent on @entity7813 induction than on @entity268 production with either low or high amounts of FSH. In addition, @entity1810 had little effect on @entity268 production stimulated by cholera toxin or @entity1928 , but amplified the actions of these ligands as well as that of @entity5987 on @entity7813 expression. @entity1810 also modulated the steroidogenic activity of the granulosa cells, with increased production of @entity1420 in response to 5-100 ng FSH. The bifunctional actions of @entity1810 on FSH-induced @entity7813 formation were observed throughout a 96-h culture period. However, the presence of the @entity2140 was not required for the first 24 h of culture, indicating that @entity1810 alters the later events involved in @entity7813 formation. @entity1810 augmented the stimulatory actions of 5 ng FSH on LH receptors in the absence or presence of insulin, but its inhibitory effect on these receptors was only observed in cells treated with insulin. These results indicate that @entity1810 modifies FSH action during granulosa cell development in a biphasic manner. @entity1810 can exert stimulatory or inhibitory effects depending upon the concentration of FSH and the presence of insulin, and these are due to alterations in @entity268 action as well as @entity268 production. Autocrine and/or endocrine actions of @entity1810 during granulosa cell differentiation may be involved in the processes of follicle selection and development.
