[Annual and circadian rhythms in plasma testosterone of five healthy young male Parisians (author's transl)].
Every other month, during the course of 14 months, the circadian rhythm in plasma testosterone (among others variables) of 5 healthy males (26 to 32 years) was documented. Subjects' synchronization : light-on at 07 +/-  1 hr; light-off at 23hr +/- 1.5 hr all the year long. Blood sampling 4-hourly, at fixed clock hours during 28 hrs, for radioimmunologic testosterone determinations. The cosinor method was used for statistical analyses. An annual rhythm in the testosterone 24-hr mean is detected (p less than 0.025) with a peak in October (from 16 July to 26 December, with 95% confidence limits). Annual mean (+/- 1 SE) - 759 (+/- 26)ng/100 ml. Peak-through difference = 107 ng/100 ml (from 106 to 290 with 95% confidence limits). The timing of the testosterone circadian peak, in the 24 hr-scale varies also in the course of the year. The peak is found around 08(00) in May and around 14(00) in November, this phase-shift being statistically significant (p less than 0.05). The sexual activity (daily self-recording) also has an annual rhythm with a peak in October.
D000328:Adult; D002940:Circadian Rhythm; D006801:Humans; D008297:Male; D012621:Seasons; D012725:Sexual Behavior; D013739:Testosterone / Q000097:blood*
D013739:Testosterone
Rythmes annuels et circadiens de la testostérone plasmatique chez cinq Parisiens jeunes, adultes et sains