Short-term variations of plasma testosterone concentrations in the European badger (Meles meles).

Badgers were sampled once during the sexually inactive season (July-November) and during the breeding season (February-April) and testosterone and dihydrotestosterone (DHT) concentrations were measured by radioimmunoassay after separation by chromatography. Concentrations of both hormones were higher in the breeding than non-breeding season, but the mean ratio of testosterone to DHT was greater in the breeding (14) than in the non-breeding season (7). During the breeding season (March 1979) 18 adult male badgers were bled at 12-min intervals for 3 h over a period of 24 h. Testosterone concentrations were measured without chromatography. An episodic pattern of release was observed. All the animals exhibited peaks of large amplitude (1-30 ng/ml) which lasted for about 2 h. The great variability in mean testosterone values for each animal (1-13 ng/ml) could also have been due to differences in individual sexual status.