Aromatase, Estrogen and Male Reproduction: a Review

Abstract

The mammalian testis is both an endocrine and an exocrine gland. In addition to gonadotropins and testosterone, estrogens are found in male gonads. Estrogens regulate male gonadal functions. Estrogens perform their functions together with estrogen receptors. Estrogens participate in functions such as pubertal growth and spermatogenesis in men. The aromatase enzyme, a product of the CYP19 gene, is important in the conversion of androgens to estrogens. Aromatase is present in Leydig cells, pachytene spermatocytes, and round spermatids in the testis. Factors such as TGFβ1, TNF-α, and TH have been shown to have a negative effect on aromatase. P450 aromatase deficiency leads to disorders such as high testosterone, infertility, shrinkage and testicular weight, decreased ejaculation, and sperm motility in men. In cases such as oligospermia that develops due to the increase in serum estrogen levels, it has been observed that the level of testosterone increases by using estrogen inhibitors. In this review, changes in male gonads in aromatase deficiency and factors affecting aromatase are stated. As a result, it has been shown that aromatase expressed in the testis is important for male gonad development and spermatogenesis.