Altered androstenedione to testosterone ratios and LH concentrations during musth in the captive male Asian elephant (Elephas maximus)

摘要

Summary. Greater concentrations of androstenedione than testosterone were usually present during periods of non-musth in plasma collected weekly for various periods up to 2 years in 8 male Asian elephants (4–35 years of age). For the 6 males that exhibited musth the androstenedione/testosterone ratio shifted greatly in favour of testosterone. The severity of musth was assessed weekly using a scale of 1 to 5 for each of 8 behavioural traits including urine dribbling, temporal gland secretion and aggression. A significant correlation (P < 0·05) was noted between plasma testosterone concentrations and the musth score value in 5 of 6 musth episodes. Brief shifts in the ratio of the two androgens when testosterone predominated (n = 106) were seen during the non-musth period in 3 of the males studied continuously for 2 years. In 82% of these instances, stimuli of a sexual or aggressive nature had occurred in the preceding 48 h (x2, P < 0·01).