DELAYED DIAGNOSIS OF PSYCHOLOGICAL ERECTILE DYSFUNCTION BECAUSE OF THE PRESENCE OF MACROPROLACTINEMIA

Idiopathic hyperprolactinemia can be found in men with either normal o r low serum testosterone (T) levels. The explanation for the differing effects on T of similar PRL levels has not been found. Macroprolactin emia, as a clinical entity, has been reported mostly in women. These m acromolecules are biologically less active and/or are transported less easily across the capillary bed than the 22-kDa molecules. Therefore, women with elevated PRL levels retain normal menses and fertility. We studied six men, aged 28-53 yr (mean, 45 yr), in whom hyperprolactine mia was initially considered to be the cause of their erectile dysfunc tion. PRL levels ranged from 25-92 ng/mL (normal, 2-15 ng/mL), but T a nd gonadotropin levels were normal, suggesting that PRL was not disrup ting gonadotropin and gonadal steroid function. The results of magneti c resonance imaging studies of the pituitary gland were normal. Separa tion by Sephadex G-100 column chromatography showed a predominance (85 -90%) of big (60-kDa) and big big (>150 kDa) PRL, in contrast to the p redominance of 22-kDa PRL in normal subjects. Nocturnal tumescence tes ting was normal, supporting the diagnosis of psychogenic impotence in these subjects, and potency returned after counseling. Hence, the biol ogically inactive macroprolactinemia did not cause any organic derange ment in erectile function. It further obscured and delayed the appropr iate diagnosis and treatment of these individuals.