EFFECT OF ROENTGEN RADIATION ON THE ESTERASE ACTIVITY OF RAT TESTIS

Since nonspecific esterase or aliesterase provides an index of the state of interstitial tissue in testis, the functional state of Leydig cells after irradiation should be indicated by this enzyme activity. Rats were made temporarily sterile by local testicular irradiation of 600 r, and enzyme activities were followed in testis 10, 20, 30, 40, and 50 days later. Activities were estimated with pnitrophenyl acetate and p-nitro valerate as substrates. The radiation-induced lesions included gradual and complete destruction of germinal epithelium, late hyperplasia of interstitial (Leydig) cells (at 30-40 days), and reduction in the number of seminiferous tubules. By the l0th postirradiation day the esterase activity with the lst substrate was increased 3-fold and that with the 2nd substrate was increased 2-fold; both total and specific activities were increased. The activities fell gradually but were still elevated to more than 50% above controls by the 50th day. The results indicate that, while radiation destroys germinal epithelial cells, it stimulates the proliferation of interstitial cells. (H.H.D.)