[Blood prolactin levels in male hypogonadism (author's transl)]

Prolactin levels were measured in 84 patients aged 20 years with hypogonadism, both under baseline conditions and after stimulation with TRH. In those with impuberty from delayed puberty or gonadotropin insufficiency, baseline blood prolactin levels were normal but the response after stimulation was reduced in a significant manner. In patients with Klinefelter's syndrome, both baseline and reserve blood prolactin levels were increased. No correlation was observed between these abnormal levels and the usual clinical and biological disturbances found in this disorder (gynaecomastia, diabetes, hyperinsulinism, changes in 5-alpha-reduction). The significance of this hyperprolactinaemia remains obscure.