Plasma prolactin and estradiol during sleep in impotent men and normal controls

There are no investigations of sleep-related changes in circulating prolactin and estradiol in impotent men without known organic pathology. This study compares plasma levels of both hormones during sleep in 17 physically healthy patients with erectile impotence and 11 normal controls. Five men had never been able to achieve intercourse (primary impotent group) and 12 suffered from a lifelong history of intermittent erectile failure (secondary impotent group). The subjects, aged 23 to 36, were studied in a sleep laboratory from 3 to 6 nights with the last two devoted to sequential blood sampling every 20 min. Samples were pooled during consecutive 2-hr periods from 11 PM to 7 AM for hormonal assessment. There were no statistical differences in sleep measures among groups. Mean prolactin and estradiol values for all subjects were within the normal range. Both impotent groups showed a significant nocturnal increase in prolactin concentration and no time-related changes in plasma estradiol. There were no statistical differences in the plasma concentration of both hormones among groups or between study nights. The results suggest that severe and long-lasting erectile failure may occur in physically healthy individuals without associated abnormalities in circulating prolactin and estradiol.