Antimullerian hormone

Antimullerian hormone (АМН) (also called Mullerian Inhibiting Substance) is the gonadal hormone. It is a member of the transforming growth factor-bb family of peptide growth and differentiation factors. АМН is produced in both male and female gonads - by Sertoli cells of the testis and granulosa cells of the ovaries. During the male embryogenesis АМН causes regression of Mullerian ducts, and testosterone stimulate the differentiation of wolffian system. During female embryogenesis, in the absence of АМН and testosterone, mullerian structures differentiate and develop into female internal genitalia and wolffian ducts regress. АМН continues to be produced by the granulosa cells of the ovary during the reproductive life of the women. АМН is known to inhibit resumption of meiosis in oocytes. Besides, АМН disturbs ovarian steroidogenesis: it decreases aromatase activity, leading to lowered estradiol production and hyperandrogenia in the follicle. АМН inhibits granulosa cells mitosis and decreases the number of LH-receptors on the granulosa cells. АМН is the antagonist of Epidermal Growth factor ( EGF) and might inhibit EGF-stimulated secretion of tissue-type plasminogen activator (tPA), which plays significant role in the ovulatory rupture of the follicle. Thus, АМН exerts inhibitory influence on all follicular components, including granulosa cells growth, steroidogenesis, oocyte maturation and follicle rupture process. It suggests, that АМН might play certain role in pathogenesis of chronic anovulation (polycystic ovaries syndrome).