Plasma testosterone during nocturnal sleep in normal men

Plasma testosterone was measured by a competitive protein binding procedure at 10 to 20 minute intervals in five normal adult men during two nights of sleep. Blood samples were obtained by means of an indwelling venous catheter while sleep was monitored polygraphically. There were 1–4 abrupt elevations of plasma testosterone concentration per night in each of the subjects with an average increase of 244 ng/100 ml ± 45.5 (SE) or 59% above the values present at the onset of the episode. The fluctuations in plasma testosterone were superimposed on a nocturnal rise of the hormone observed in seven of the nights. The average of all samples taken during each hour period through the ten nights revealed a highly significant (P<0.001) nocturnal increase in plasma testosterone. The findings did not support the existence of a relation between REM sleep and an increase in testosterone levels.