NEPHROTOXIC EFFECTS OF MONOMETHYLHYDRAZINE IN MONKEYS

Abstract : The increased emphasis on use of monomethylhydrazine (MMH) as a propellant in space systems has made it necessary to determine the toxic effects of this compound. Previous studies indicated a nephrotoxic effect in dogs after MMH exposure. This study was designed to determine possible effects on kidney function in monkeys following single and repeated injections of MMH. Renal function tests and needle biopsis for electron microscopic examination of kidney tissue were performed on monkeys exposed to MMH. The left kidney of each animal was surgically translocated to a subcutaneous pocket and baseline needle biopsy samples taken; baseline renal function tests, i. e., glomerular filtration rate, renal plasma flow, and maximum tubular excretion rate, were determined. One group of monkeys was exposed to a single injection of 7.5 mg/kg MMH, one group to 2.5 mg/kg daily for 14 days, one group to 5.0 mg/kg every other day for 14 days, and one group to 5.0 mg/kg daily for 5-10 days. The renal function tests were repeated 24 hours after the final exposure and renal biopsy samples taken 48 hours after exposure. There was no statistically significant change in the renal function tests in any group. However, examination of the renal biopsy samples revealed major changes in the subcellular morphology in all groups of monkeys following MMH exposure.