Effects of Insulin on Excretion of Nitrogen in Normal, Depancreatized, and Steroid-Diabetic Rats

Sexually mature male rats in metabolism cages were adapted to the tube-feeding of a medium carbohydrate diet. In experiment 1, intact rats were fasted for 96 hrs. Injection of glucagon-free insulin caused an increase in urinary NPN. Cortisone caused a greater loss of NPN which was not significantly changed by addition of insulin. In experiment 2, intact tube-fed rats excreted amounts of NPN and glucose increased in proportion to the dose of cortisone. Glycosuria but not nitrogen loss was suppressed by insulin. In experiment 3, the spontaneous glycosuria of partially depancreatized rats was suppressed by insulin and the elevated urinary NPN was also suppressed. When the glycosuria of partially depancreatized rats was induced or aggravated by cortisone it could be suppressed by insulin but the level of urinary NPN remained high.