Figure 1.

Suggested pathophysiologic vicious cycle for explanation of the possible beneficial role of GnRHa in minimizing the gonadotoxic effect of chemotherapy. Alkylating agents such as cyclophosphamide destroy many follicles; therefore, the levels of estrogens and inhibins are reduced, bringing about an increase in FSH secretion, due to decreased negative feedback. The increased FSH recruits many follicles to enter the unidirectional path of folliculogenesis, to be destroyed by the alkylating agents. The GnRHa, by its effect to prevent increased gonadotropin concentration, may minimize this vicious cycle. The AMH may also play an important role in this pathophysiologic process. AMH indicates anti-Müllerian hormone; FSH, follicle-stimulating hormone.