TESTICULAR HYPERTROPHY IN RATS

Abstract

Experiments on hypertrophy of the testis have been carried out by Lipschutz (1922) who stated there was accelerated growth of the contralateral testis which rapidly reached maximum weight, but that no true hypertrophy occurred after unilateral orchidectomy. Grant (1955) stated that an increase in testicular volume occurred after unilateral orchidectomy in three albino rats. Shellabarger (1963) stated there was no increase in testicular weight after removal of a single testis. Being an endocrine organ, the interstitial cells, including Leydig cells, of the remaining testis should reflect the effects of unilateral castration. Since spermatogenesis is hormonally controlled, the seminiferous tubule might be expected to respond by enhancing gamete production as do solitary remaining ovaries after unilateral spaying. The present work was designed to re-examine the above observations. One hundred and fifty Sprague-Dawley rats weighing 80 to 100 g were used in the experiments. The animals were divided into three groups. The control group (Group 1) consisted of fifty rats, which were weighed and kept for 4 weeks, and then killed and re-weighed at autopsy. The testes were also removed and weighed. Group 2 consisted of fifty rats, each ofwhich was subjected to right unilateral orchidectomy. These were killed 4 weeks later and weighed. The remaining testis was removed, weighed, fixed in Zenker's solution, sectioned at 6 \g=m\thickness, and stained with haematoxylin and eosin. Group 3 also consisted of fifty rats, each of which was subjected to right unilateral orchidectomy. Testosterone cypionate, 0-05 ml, was injected twice a week subcutaneously for a total of 10 mg testosterone weekly. These rats were then killed 4 weeks later and weighed. The remaining testes were weighed and fixed, and then sectioned and stained with haematoxylin and eosin. The value was calculated by testicular weight over body weight ofeach animal (TW/BW in Table 1). All the testes were sectioned at right angles to their longitudinal axes at the widest point and a complete cross-section count of both the tubules and interstitial cells was made. The tubular diameters were then measured. The average pre-operative body weight was 87 g for the rats in Group 1, 82 g for those in Group 2, and 83 g for those in Group 3, while the average weight at autopsy was 236 g, 212 g and 200 g, respectively. The average weight for the left testis of rats in Group 1 at autopsy was 1-30 g, while the average weight of the remaining testis in Group 2 was 1-27 g,