we studied the testis of wistar rats weighing 280-300 gms . following the administration of a single , acute intracardiac dose of methionine-enkephalin ( 100 microliters of 50 % met-enkephalin solution ) , or a chronic intramuscular dose ( 50 microliters of 40 % met-enkephalin solution ) .
C0014298
enkephalin
C0014295
met-enkephalin