Inhibition of testicular and somatic development after treatment of the postnatal rat with the Leydig cell cytotoxic ethylene dimethanesulphonate

Abstract
The Leydig cell cytotoxic ethylene dimethanesulphonate (EDS) was administered s.c. daily (50 mg/kg) to male rats aged 5–16 days. Apart from loss of weight and that the eyelids unfused earlier, no gross toxicity was observed during treatment. On day 17 testis weights, serum testosterone concentrations, testicular serum testosterone content and 125I-labelled human chorionic gonadotrophin (hCG) binding to testicular homogenates were reduced. Serum LH and FSH concentrations were elevated. The testes did not recover from EDS treatment and at 63 and 120 days were minute (125I-labelled hCG binding to testicular homogenates were reduced but not absent. Serum LH and FSH concentrations were increased. Light microscopy of the adult testes showed that EDS treatment inhibited the development of the seminiferous tubules. Most of the tubules were devoid of germ cells and Sertoli cells were rare. Occasionally tubules also contained spermatogonia and spermatocytes but no signs of spermiogenesis. The testes were composed mainly of closely packed interstitial tissue with no lymphatic space. The interstitial cells resembled Leydig cells and stained for 3β-hydroxysteroid dehydrogenase. Histochemically identified Leydig cells were absent during treatment but reappeared when treatment was withdrawn. Testicular Leydig cell numbers were only 7% of control values in the 63-day-old EDS-treated rat. The effect on the testis of EDS treatment administered at a crucial time of testicular development may be explained by withdrawal of androgen; however, the systemic effects indicate non-specific toxicity so any explanation of these changes must be viewed with caution. J. Endocr. (1988) 119, 467–474