Putrescine turnover in kidneys of testosterone-treated mice

Putrescine turnover was studied in testosterone stimulated mouse kidney after labeling the endogenous pool of putrescine with the polyamine precursor [3H]ornithine. Renal putrescine was rapidly labeled after the administration of radioactive ornithine, reaching maximal activities at the time of the earliest measurement (5 min after injection). The content of labeled putrescine then declined extremely rapid with a half-life of about 15 min. Treatment with the diamine oxidase inhibitor, aminoguanidine, did not affect this rapid turnover. The decline in radioactive putrescine was not accompanied by an increase in labeled spermine. However, testosterone treatment resulted in a marked increase in urinary content of both labeled and unlabeled putrescine indicating that most of the newly synthesized renal putrescine is excreted in the urine.