Evaluation of the endocrine functions in dystrophia myotonica

Investigation of several endocrine functions was performed in seven patients with dystrophia myotonica (DM). All patients had hyperinsulinemia. Whereas the four female patients had normal pituitary-gonadal function, all three male patients presented evidence of a primary gonadal failure. Thyroid function was normal in all patients. Four patients displayed abnormal diurnal variations of cortisol secretion. Basal prolactin levels were elevated in three patients, one of whom also had consistently elevated levels of growth hormone. The investigation adds some new evidence of neuroendocrine dysfunction at the hypothalamic level in DM.