Inositol phosphoglycans and the regulation of the secretion of leptin:: In vitro effects on leptin release from adipocytes and the relationship to obesity

The ratio of two families of inositol phosphoglycans (IPG-A:IPG-P),, insulin second messengers, is raised in non-insulin-dependent; diabetes mellitus (NIDDM) and obesity. It is shown here that IPG A type inhibits leptin release from adipocytes, contrasting with the action of insulin (stimulation) and IPG P type (no effect). The significance of inhibitory effects of IPG A type on leptin release is important in relation to obesity and NIDDM in view of the action of leptin in promoting Lep expression and fat oxidation in muscle, in addition to its effects on. satiety. Energy conservation and oxidation via interorgan regulation by leptin could be compromised by a rise in the IPG-A:IPG-P ratio. (C) 2000 Academic Press.