CHANGES IN RENAL FUNCTION PRODUCED BY MORPHINE IN NORMAL DOGS AND DOGS WITH DIABETES INSIPIDUS

¹ Department of Pharmacology, Baylor University College of Medicine, Houston 5, Texas
² Medical Department, Field Research Laboratory, Fort Knox, Kentucky

In normal dogs and dogs with diabetes insipidus, morphine causes a prominent reduction in glomerular filtration rate, renal plasma flow and the TmG for a period of several hours. In some animals, morphine abruptly eliminates all renal function, as measured by clearance techniques, for a period of ten to forty minutes. Smaller doses of morphine have an antidiuretic effect in both normal dogs and dogs with diabetes insipidus without producing appreciable changes in glomerular filtration rate, renal plasma flow or the TmG. Morphine antidiuresis appears to be due to at least two effects: (1) reducing the number of active nephrons, and (2) by acting as a stimulus for the release of antidiuretic hormone. The antidiuretic action of small doses of morphine in dogs with diabetes insipidus, when no change in glomerular filtration rate occurs, may be due to accessory antidiuretic hormone elaborating tissue.