[The inhibitory effect and its mechanism of transferrin on FSH-induced differentiation of granulosa cells].

Transferrins are a class of related metal-binding transport glycoproteins for transporting iron to various organs and tissues of the body. In recent years, it has been reported that the transferrin can play an important role in the local regulation of ovarian function, apart from its iron-binding characteristic. Transferrin could attenuate FSH-induced differentiation of rat and human granulosa cells and its mechanisms were considered as follows: (1) Transferrins partially blocked the binding of FSH with its receptors on granulosa cells and reduced the formation of intracellular cAMP, and therefore inhibited the expression of FSH receptors. (2) Acting sites beyond cAMP formation also existed for the inhibitory effect of transferrin on inhibin and estradiol production. (3) The inhibitory effect of transferrin seemed not to be involved in the changes of protein kinase C activity, the calcium release and "proliferation-differentiation reversed mechanism" in granulosa cells.