RESUMO
Obesity has recently become one of the most important public health problems. It is associated with a high rate of mortality, mainly because of cardiovascular disease, and can cause hormonal abnormalities such as hypogonadotropic hypogonadism. Weight loss is very beneficial for obese patients, because it results in improvement or even normalization of these conditions. In this report, we describe a morbidly obese patient with hypogonadotropic hypogonadism, which was probably caused by hyperprolactinemia and exacerbated by obesity-induced hormonal imbalances. After medical treatment for hyperprolactinemia and bariatric surgery, the patient's hormonal status became normal. Although morbid obesity can cause hypogonadotropic hypogonadism in men, the differential diagnosis should include other potential causes of hypogonadism if free testosterone levels are below normal.