An investigation on the effect of N-nitrosopyrollidine on the rabbit liver and kidney glutathione-S-transferase activity in vitro İn vi̇tro şartlarda N-ni̇trozoproli̇di̇n'i̇n tavşan karaci̇ǧer ve böbrek glutatyon -S- transferaz akti̇vi̇tesi̇ne etki̇si̇ni̇n araştirilmasi