The uptake in the pancreatic islets of nicotinamide, nicotinic acid and tryptophan and their ability to prevent streptozotocin diabetes in mice.

The uptake of the nicotinamide adenine dinucleotide (NAD)-precursors nicotinamide, nicotinic acid and tryptophan in the pancreatic islets of mice was studied by use of autoradiographic methods. The ability of these substances to prevent streptoxotocin diabetes was studied in the same species. It was found that only nicotinamide was strongly accumulated in the pancreatic islets and nicotinamide was also the only NAD-precursor which protected against the streptoxotocin diabetes. Apparently there is a relationship between the ability of the NAD-precursors to be taken up in the pancreatic islets and their ability to prevent streptoxotocin diabetes.