Modifiers of the secretion of FSF and LH
The secretion of the sexual pituitary hormones is controlled by GnRH which stimulates them and gonadal hormones which reduces them by a negative feedbacK mechanism.
Two glycoproteins, of theTGF-beta (transforming growth Factor-beta) family secreted by the gonads take part in the regulation of secretion of FSH: inhibin which reduces it and activin which stimulates it. In the follicular fluid there is also a protein called follistatin whose role is poorly understood but which binds inhibin and activin. Moreover, in blood inhibin and activin are bound to alpha-2 macroglobulin.
Among artificial hormonal compounds inhibiting FSH and LH secretion and consequently that of estradiol and progesterone, danazol has a particular place. It has an androgenic effect explained by its chemical structure derived from that of ethisterone. Danazol is used for the treatment of endometriosis and hereditary angioneurotic edema. This last disease is characterized by a deficiency of C1 inhibitor and danazol induces its hepatic synthesis. Its adverse effects result from its androgenic effect (acne, seborrhea, hirsutism, voice modification, fluid retention, etc) and from the inhibition of gonadostimulin secretion
Others such as clomifene increase the secretion of FSH and LH by suppressing the negative feedbach of estradiol on the hypothalamic- pituitary complex. It is used for the treatment of female infertility due to anovulation. Its principal adverse effect is ovarian overstimulation resulting primarily in abdominal pains as well as the possibility of multiple pregnancies. It can give visual disorders through mechanisms which are not well understood.
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