Paracrine Regulation of Reproductive Function by Inhibin and Activin

Abstract

Conclusions

Inhibin has been confirmed as a factor produced in the gonads and capable of specifically regulating FSH release by the pituitary. However, inhibin and the related activins seem to play important paracrine roles in locally regulating testicular and ovarian function. They are also involved in paracrine regulation in the placenta, the pituitary, and other nonreproductive tissues. The local effects of these factors may be modified by the presence of binding proteins and the receptor or receptors expressed.

The specific type of activin or inhibin produced and the net effect locally may vary as a function of the sexual development of the organism or the stage of the reproductive cycle. A more complete understanding of these complex relationships will develop with advances in our ability to measure the proteins, their binding proteins, and cell surface receptors.