Uterine arginase inhibition affect the rat embryonic development.

The presence of polyamines (putrescine, spermidine and spermine) and the enzymatic activity of extrahepatic arginase (E.C. 3.5.3.1) which catalizes the hydrolysis of L-arginine into L-ornithine and urea have been related with cellular growth and development in several tissues. The enzymatic activity of arginase in rat implantation sites and its participation in reproductive process is demonstrated. Long-Evans adult rats during the 4th or 5th days of pregnancy were utilized. Arginase activity is higher in non-decidualized tissue (86.1 +/- 33 nmoles of urea/mg protein/min-1) when was compared with implantation sites (61.7 +/- 17). Intrauterine administration of several concentrations of a new synthetic L-ornithine analogue, AIAVA (2-amine-5-iodoacetamide valeric acid), produced embryonic growth arrest concomitant with arginase inhibition but not ornithine decarboxylase. From our results it is possible to stress the metabolic importance of uterine arginase in reproductive process.