Plasma androgen patterns during delayed implantation in the European badger (Meles meles L.)

Androstenedione and testosterone were measured by radioimmunoassay after chromatography on celite microcolumns throughout the delayed implantation period in the European badger (Meles meles L.). Androstenedione and testosterone concentrations varied from 0.05 to 22 ng/ml, and from 30 pg/ml to 359 pg/ml, respectively. There was a typical biphasic pattern in the fluctuation of these two steroids. Androstenedione levels increased between June and August (X= 7.9 +/- 0.8 ng/ml), decreased from September to November (X = 2.3 +/- 0.3 ng/ml), and then increased again from December to February (X = 6.1 +/- 0.7 ng/ml). The same fluctuations of the testosterone levels were observed throughout the diapause, but the concentrations were lower. The overall correlation between androstenedione and testosterone was highly significant (r = 0.75, P less than 0.001). There was also a similarity between the androgen and progesterone patterns of secretion (r = 0.31), particularly at the end of the delay period (r = 0.73, P less than 0.001). No correlation could be demonstrated between androgens and estrogens.