In Vitro Insulin Stimulatory Effect on Glucose Uptake and Glycogen Synthesis in the Gills of the Estuarine Crab Chasmagnathus granulata

Abstract

The aim of the present study was to examine the effects of insulin on glucose uptake and glycogen synthesis in crab Chasmagnathus granulata gills. We observed an increased glucose uptake and incorporation of d-[14C]glucose into glycogen when posterior C. granulata gills were incubated in the presence of insulin; however, this was not observed in anterior gills, despite the presence of similar insulin receptors. In posterior gills, basal glucose uptake in the summer was significantly higher than in the winter. Moreover, in the summer, the insulin dose required to stimulate glucose uptake was twice as high as in the winter. However, there was no significant difference in terms of basal glycogen synthesis in summer and winter. In crustaceans, the endogenous insulin/IGFI substance might be involved in the rapid restoration of glycogen levels in the gills, increasing glucose uptake and glycogen synthesis. Bovine insulin seems to have a stimulatory effect on glycogen metabolism only in posterior gills.