Glucose-6-phosphate dehydrogenase and 'malic' enzyme activities during adaptive hyperlipogenesis in migratory starling (Sturnus roseus) and white wagtail (Motacilla alba)

Abstract

The changes in the activities of glucose-6-phosphate dehydrogenase and 'malic' enzyme in the liver and adipose tissue were studied in two migratory birds, viz., rosy pastor and white wagtail, which have different dietary habits during their post- and pre-migratory periods. Activities of both the enzymes in the liver of these birds increased during their premigratory period which correlated well with premigratory hyperlipogenesis. It is suggested that hyperphagia, diet, and hormones are involved in induction of the enzyme activities and premigratory hyperlipogenesis. Data on enzymatic studies indicate that 'malic' enzyme catalyzed reaction plays a major role in generation of NADPH2 and the liver is the main site for lipogenesis in these birds.