ADP-ribosylation of isolated rat islets of Langerhans

Incubation of isolated rat islets of Langerhans with [adenine-2,8-3H]NAD+ results in rapid incorporation of 3H into acid-insoluble products. The major site of incorporation appears to be the cell membrane. The reaction is inhibited by nicotinamide, an ADP-ribosylation inhibitor, and stimulated by arginine, an ADP-ribose acceptor. The results demonstrate that islet membrane proteins can be ADP-ribosylated in the absence of exogenous ADP-ribosylating agents and suggest that ADP-ribosylation plays a role in pancreatic islet cell function.