RESUMO
Seven healthy and sexually adult bulls were slaughtered and their reproductive system was isolated. Different tissues including: testes, epididymis, vas deferan, ampulla, accessory sex glands [seminal vesicle, prostate and bulbourethra], muscular and mucosal layer of pelvic and penile urethra were carefully dissected. Total soluble protein and arginase specific activity [ASA] were measured by Lowry and modified paranitrophenylglyoxal [PNPG] method, respectively. The results indicate that the highest arginase specific activity [51.28 +/- 8.79 x10[-3] IU/mg of protein] is present in muscle of pelvic part of urethra. Based on ASA, bulls reproductive system was categorized in three tissue groups: high, medium and low. Muscular layer of penile urethra with the highest ASA level [> 50 X10[-3] IU/mg tissue protein] is in the 1st group, Testes, bulbourethral gland and mucosal layer of penile urethra [30-40 X10[-3] IU/mg tissue protein] are in the2nd group and the rest parts [<25 X10[-3] IU/mg protein] are in 3rd group. Significant differences observed between classified tissues [p<0.05]. The present study indicate that ASA is present at different levels in all parts of bull reproductive system. This condition may be related to different rate of cell proliferation and differentiation or some other unknown physiological and biochemical activities of the enzyme in this system