The Annual Testicular Cycle and Androgen Production in Vitro in the Masked Civet Cat, Paguma L. Larvata

Summary. The seasonal changes in the capacity of the testicular tissue of the masked civet cat, Paguma l. larvata, to produce testosterone from radioactively labelled pregnenolone in vitro, has been measured chromatographically, together with an analysis of the spermatogenic cycle and the lipid cycle of the interstitial Leydig cells. Testosterone is the main androgen produced by the civet cat testis in vitro and its production, assessed as a percentage conversion from the precursor added, closely follows the interstitial lipid cycle and seasonal spermatogenic cycle, reaching a peak in March and rapidly declining at the end of the reproductive season. The most active period of testosterone production takes place at a time when the interstitial cells are becoming rapidly depleted of their lipids, and the very rapid decline which takes place in July is marked histochemically by the interstitial tissue entering a heavily lipoidal end-phase. The possible relationship between the seasonal histochemical events and the rate of androgen synthesis is discussed.