What is the role of hypogonadism in the etiology of gynecomastia?

Updated: Mar 22, 2018
  • Author: George Ansstas, MD; Chief Editor: George T Griffing, MD  more...
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Conditions that result in primary or secondary hypogonadism can lead to gynecomastia in different mechanisms. Primary hypogonadism can be related to a congenital abnormality such as Klinefelter syndrome, an enzymatic defect in testosterone biosynthesis, infection, infiltrative disorders, testicular trauma, or aging. The associated reduction in testosterone production leads to a decrease in the serum testosterone concentration and a compensatory rise in leuteinizing hormone (LH) release. The excess LH results in enhanced Leydig cell stimulation with inhibition of the 17,20-lyase and 17-hydroxylase activities and increased aromatization of testosterone to estradiol; the net effect is an increase in estradiol relative to testosterone secretion. [15]

Secondary hypogonadism due to a hypothalamic or pituitary abnormality may also be associated with gynecomastia. In these patients, the production of LH is deficient, resulting in a low testosterone production rate and low estradiol production from the testes. However, the adrenal cortex continues to produce estrogen precursors that are aromatized in extraglandular tissue; the result is an estrogen/androgen imbalance.

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