Seasonal variations in cholesterol concentration in the testis, adrenal, liver and plasma of the Indian palm squirrel Funambulus pennanti (Wroughton)

Abstract

Cholesterol concentration in the testis, adrenal, liver, and plasma has been estimated in the male five-striped Indian palm squirrel. The palm squirrel is a seasonal breeder and is reproductively active from January to July. A period of regression ensues during August-September, followed by a period of quiescence (October-November) when the testes are regressed. The recrudescence of the gonads and restoration of reproductive activity occur in December, followed again by the breeding season in January. The seasonal variations of the concentration of cholesterol are correlated with different phases of reproductive activity of the squirrel. The concentration of testicular cholesterol, which is minimal in the quiescent season when the testes are reproductively inactive, is maximal in the regressing season. There is an apparent inverse relationship between the adrenal and plasma cholesterol concentration. In the active season the level of adrenal cholesterol is maximal, while that of serum cholesterol is minimal; it is the reverse in the recrudescent season. The significance of the varying concentrations of cholesterol in the liver, adrenal, plasma, and testis with reference to each other is discussed.