Many young men with Type 2 diabetes have abnormally low levels of testosterone, new research shows.
Their lack of the hormone may have "profound" implications for their sexual and reproductive health, Dr Paresh Dandona of the State University of New York at Buffalo and his colleagues warn. "Whatever else is happening with diabetes and heart disease ... gross sexual dysfunction and infertility could be part of the story," Dandona told Reuters Health.
In 2004, Dandona and his colleagues reported low testosterone levels in middle-aged men with Type 2 diabetes, as well as "inappropriately low" levels of luteinizing hormone and follicle-stimulating hormone, which are essential to fertility. In the current study, the researchers tested hormone levels in 38 men with Type 1 diabetes and 24 with Type 2 diabetes, all of whom were between 18 and 35 years old. While testosterone, luteinizing hormone, and follicle-stimulating hormone levels in the type 1 diabetics were "perfect," Dandona said, with just 8% of them having subnormal testosterone levels.
One third of the Type 2 diabetics had testosterone levels that were below normal and 58% had testosterone levels below normal for their age. Men with low testosterone levels also had low luteinizing hormone and follicle-stimulating hormone levels, indicating that they met diagnostic criteria for hypogonadotrophic hypogonadism, a condition in which the testes are unable to function properly due to problems with the hypothalamus or the pituitary gland.
Obesity and insulin resistance play big part
According to Dandona, obesity, as well as insulin resistance and inflammation, likely work together to impair the hypothalamus' ability to trigger the hormonal cascade responsible for producing the necessary amounts of testosterone, luteinizing hormone, and follicle-stimulating hormone.
Treating hypogonadotrophic hypogonadism requires not only giving men testosterone to boost sex drive, but also injections of luteinizing hormone and follicle-stimulating hormone to restore fertility, the researcher said. It's not clear, he added, whether losing weight would restore hormonal balance in Type 2 diabetic men with hypogonadotrophic hypogonadism. Dandona hypothesises that "by the time you develop diabetes and you've got this problem, the reversibility element is largely gone."
Dandona and his colleagues have also found that "in some of these people semen analysis reveals hardly any spermatozoa," although they have not yet published this research. They are now planning additional research to determine if Type 2 diabetes-related hypogonadotrophic hypogonadism in men is reversible with weight loss, as well as to understand how hypogonadotrophic hypogonadism affects sexual health and fertility in these men. – (Reuters Health, September 2008)
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