REGULATION OF TESTICULAR INFILTRATION IN ACUTE LYMPHOBLASTIC-LEUKEMIAOF THE RAT

The testis is a common site of relapse in childhood acute lymphoblasti c leukaemia (ALL). In adults, testicular relapses of ALL are very rare . A similar age-difference in the frequency of the testicular infiltra tion exists also in therat T-cell leukaemia. In the present investigat ion, the effect of various hormonal treatments and unilateral cryptorc hidism on the form of testicular infiltrates by the rat T-cell leukaem ia was studied. Inhibition of testicular activity by estradiol treatme nt (E(2)) of early pubertal rats injected i.p. with rat T-leukaemic ly mphoblasts significantly decreased the proportion of the testis occupi ed by leukaemic infiltrates. The proportion of the testis occupied by leukaemic infiltrates was significantly higher in the abdominal testes of both early and late pubertal unilaterally cryptorchid rats, than i n the scrotal testes of leukaemic control rats. Daily treatment of ear ly pubertal rats with human chorionic gonadotrophin (hCG), or human me nopausal gonadotrophin (hMG), did not have an effect on testicular leu kaemic infiltration. These studies demonstrate that the leukaemic infi ltration of the testis is influenced bythe changes in the physiologica l activity of the testes.