Seasonal variations in plasma luteinizing hormone and testosterone levels in the European badger Meles meles L

Although active spermatogenesis occurs throughout the year in the male European badger Meles meles L., seasonal fluctuations of testicular activity were observed. The present study compared the pattern of luteinizing hormone (LH) and testosterone (T) secretions throughout the annual cycle. LH secretion was investigated by means of a heterologous radioimmunoassay using anti-ovine LHβ antiserum and canine reference standard. Seasonal and nycthemeral changes in LH and T secretions were observed. During the year a period of maximal values for both hormones is well correlated with the breeding. Moreover, episodic LH releases occurs during the period of minimal testosterone values, indicating resumption of hypothalamo-pituitary activity well before the breeding period.