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Hyperestrogenism in men with Klinefelter’s syndrome linked with CYP19 expression
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The Endocrine Society's 91st Annual Meeting
Lower testosterone levels were associated with an increased conversion rate of testosterone to estradiol and a significantly higher expression of CYP19 in the testis of men with Klinefelter’s syndrome.
“Since estradiol lowers testosterone production through negative feedback, this study links the clinical observation of hyperestrogenism in men with Klinefelter’s syndrome with CYP19 expression data,” the researchers wrote.
The researchers set out to identify the molecular basis of hypogonadism in men with Klinefelter’s syndrome. They examined 120 testicular samples from men with obstructive azoospermia, non-obstructive azoospermia and Klinefelter’s syndrome.
After a 24-hour incubation with luteinizing hormone, men with Klinefelter syndrome had a 25% decrease in testosterone production compared with men with non-obstructive azoospermia (P=.035). Men with Klinefelter’s syndrome had a four-time higher estradiol to testosterone ratio compared with men with non- obstructive azoospermia (P=.03).
Further, men with Klinefelter’s syndrome had a 4.15 times higher expression of CYP19 per mg of testicular tissue. Aromatase CYP19 was expressed in Leydig and Sertoli cells only, with predominant expression in Sertoli cells.
“Our data provide scientific rationale for the use of aromatase inhibitors in men with Klinefelter’s syndrome,” the researchers concluded.
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