[Effects of met-enkephalin on the testis. II. Histochemical study]

We performed a histochemical study using the Alcian blue-PAS staining method (for mucopolysaccharide), vitamin C, Sudan black (for lipids), and methyl green-pyronine (for nucleic acid). For the study, we utilized 105 male Wistar rats weighing 280-300 gms. Thirty rats comprised the control group, and 75 comprised the study group. Rats in the study group received a single, acute intracardiac dose of met-enkephalin (100 microliters of 50% met-enkephalin solution) and were sacrificed at 15, 30 and 60 minutes following injection, or a chronic intramuscular dose (50 microliters of 40% met-enkephalin solution). We observed that met-enkephalin caused histochemical changes in the rat testis, as evidenced by the accumulation of mucopolysaccharide (early in the study), cytoplasm lipid degeneration, changes in protein synthesis, and a fall in vitamin C stores (in seminal epithelium cell lines, as well as Leydig cells). These changes were more marked in the chronically than in the acutely-treated rats. The foregoing findings demonstrate that enkephalins (endogenous opiates) can cause profound metabolic changes in the rat testis that affect all its metabolic elements [proteins, lipids, polysaccharides and active substances (vitamins...)].