Hypothalamic-pituitary function in myotonic dystrophy.

Function of the hypothalamic-pituitary axis was investigated in seven patients with myotonic dystrophy (MD). HGH and ACTH secretion were normal. TSH response to TRH was impaired in about half the cases, without concomitant thyroid dysfunction. LH and FSH levels were often elevated, with inconsistent response to LH-RH stimulation, Gonadotrophin disturbances in MD have previously been attributed to a primary gonadal lesion, characteristically seen in this disease. High prolactin levels in six of our seven patients however suggest that gonadal failure may be also be due to hyperprolactinemia through the direct anti-gonadal effect of prolactin and its interference with hypothalamic-pituitary regulation of gonadotrophin secretion.