Abstract
Neutral lipids (Sudan positive substances), unsaturated lipids and plasmalogen were demonstrated in liver, fat body, kidney, adrenals, testis, intestine and cardiac muscle of toad (Bufo melanostictus) during hibernation (February), post-hibernation (April), breeding season (August) and prehibernation (November).
In liver and fat body maximum sudanophilia has been observed during November, with decrease during February and complete disappearance during April. In August it began to accumulate again. Unsaturated lipid and plasmalogen were absent in February and rose to a maximum during August. These changes indicate that fat is being utilized during hibernation. In testis a maximum of unsaturated lipid and plasmalogen have been observed during August and a minimum during February. In February accumulation of neutral fat has been observed in the intertubular and intratubular space of this organ. In adrenals maximum sudanophilia, unsaturated lipid and plasmalogen have been observed during February, with minimums during August. These changes in testes and adrenals indicate hypofunction of the glands during hibernation. In kidney and intestine a maximum of unsaturated lipid and plasmalogen has been seen during August, with a minimum during February; cardiac muscle showed very little alteration in the lipid fractions. These changes have been ascribed to seasonal alteration in the activity of the organs; the heart, being a vital one, showed minimum alteration.