Physiological correlates of musth: lipid metabolites and chemical composition of exudates.

Physiological changes related to lipid metabolism, behavior, and chemicals released in body exudates were studied during musth in the Asian elephant, Elephas maximus, as a case study. During musth, changes in serum testosterone and triglyceride concentrations followed similar patterns, with the former increasing sooner than the latter. Deviant behavior increased during changing androgen levels. The observed high concentrations of testosterone were positively and significantly correlated with increased triglycerides. Lipase activity elevated significantly immediately before and after musth. Blood pH increased significantly in alkalinity. Urine and temporal gland secretions released variable amounts of compounds, some of which may be chemical signals. During musth, temporal gland and urinary exudates demonstrated increased acetone and other ketones indicative of lipid metabolic alterations. Large quantities of nonmethane hydrocarbons, especially 2-butanone, were released from the seemingly dry orifice of the temporal gland before the start of overt musth and before maximum blood elevations were observed; isoprene release was similar. However, maximal acetone levels occurred simultaneously in blood, temporal gland secretions, and urine. Metabolically, musth is a series of interwoven, changing stages of increasing and decreasing hormones and lipid-related constituents. Released chemicals can be quantitatively related to these internal physiological events; some observed behaviors appear to result from altered chemical signals.