EFFECT OF HOST FASTING AND SUBSEQUENT REFEEDING ON THE GLYCOGEN METABOLIZING ENZYMES INHYMENOLEPIS DIMINUTA(CESTODA)

Abstract

During host fasting, total glycogen synthase activity in Hymenolepis diminuta increased to a maximum at 48 h and decreased thereafter. The activity ratio of glycogen synthase I to total glycogen synthase(I/T), however, decreased before rising again. The increase in the active form of glycogen synthase after 48 h of host fasting might prevent complete exhaustion of glycogen during prolonged starvation. The total and active glycogen phosphorylase activities increased throughout the whole fasting period.Twenty-four hours after refeeding the fasted host, the glycogen synthase and phosphorylase activities in H. diminuta decreased. In vitro studies, however, revealed an immediate increase in the glycogen synthase activity when glucose was available.Protein content of worms artificially reduced in length, from normal hosts was comparable to that of the 48 h starved worms but not to their glycogen content, glycogen synthase, and phosphorylase activities.