Plasma testosterone and sleep: relationship to sleep stage variables.

A study was performed to determine whether the pattern of secretion of testosterone (T) during the night bears a systematic relationship to the cyclically recurring periods of rapid eye movement (REM) and non-REM (NREM) sleep. In four healthy male volunteers, 10-20 min sampling of plasma for T was carried out through a long indwelling catheter in conjunction with all-night polysmonography. Analysis of plasma T, comparing the samples drawn during the REM and NREM stages, did not reveal a significant difference in the mean concentration of T between the two sleep stages or among specified time segments of the NREM-REM cycles. A more exacting approach to exploring for a correlation of the secretory pattern with the sleep-stage cycle was then undertaken. This method used the NREM-REM cycle as the independent variable in the analysis. We were able to demonstrate that the positions of the peaks and troughs of T concentration in each REM-NREM cycle are discriminable when examined in relation to the time of REM sleep onset in each cycle. The tendency for peaks in T concentration to be associated with repetitive inaugurations of REM sleep is coordinate with a pattern of serial "upswing" in T concentrations that occurs in the period from 30 to 10 min before the transition from NREM to REM sleep. Accordingly, it proved possible to demonstrate certain signs of interaction between the activity of the pituitary-gonadal system and the mechanisms that regulate central nervous system state in sleep. The more traditional parameter of comparison (mean concentration of hormone in REM and NREM sleep) did not detect the association.