Decreased androgen levels and obesity in men.

Obesity in males is accompanied by a significant decrease in testosterone levels. This decrease is essentially a consequence of the decrease of the sex hormone binding hormone (SHBG) binding capacity, itself probably the consequence of the increased insulin levels. In moderate obesity, free testosterone levels are normal, however, and there does not exist a real hypogonadism. In massively obese males, on the other hand, there is real hypogonadotrophic hypogonadism, with decreased free testosterone levels. The latter are the consequence of functional alterations at the hypothalamopituitary pole of the testicular axis, characterized by a decreased amplitude of the LH pulses. The decrease in adrenal androgen (DHEAS) levels is moderate and although it has been claimed that the increased insulin levels may play a causal role, the exact mechanism of this decrease is still a matter of controversy.