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 of which 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 of each 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, 537

Morphometric Studies of Compensatory Testicular Hypertrophy in the Rat after Hemicastration

“…The results of volume fraction estimations of the testicular components showed that the hemicastrated testis contained more interstitial space, but there was no difference in the volume fraction of interstitial cells. This does not support the results of Liang and Liang (1970) who concluded that the increase in testicular weight after hemicastration was due in part to an increase in the interstitial cell number.…”

“…Previous work reported an increase in the seminiferous tubule diameter of the contralateral testis after unilateral castration in the rat (Liang and Liang 1970), toad (Thyagaraja and Sarkar 1970), bull (Johnson 1978), and ram (Voglymayr and Mattner 1968;Johnson et al 1971). The present results also found that the area of the seminiferous tubule of hemicastrated rats was significantly larger than that of intact animals.…”

“…The increase in weight of the remaining testis after unilateral castration appeared to be due to an increase in Sertoli cell numbers (Cunningham et al 1978), but testicular hypertrophy occurring in hemil;:~~trated young puberal rats was thought by Liang and Liang (1970) to be due in part to an increase in the interstitial cells, and was not true hypertrophy of the tubules. In the ram, it was reported that diameter (V oglmayr and Mattner 1968) and length (Hochereau-de Reviers et al 1976) of the seminiferous tubules of hemicastrated aniinals were significantly greater than in intact animals.…”

The Effect of Neonatal Vasectomy on Testicular Function

“…The authors concluded that the inferior spermatic nerve that runs along the ductus deferens and provides a minor supply of testicular innervation (Kuntz and Moris -1946;Hodson -1970) is involved in the testicular hemicastration response. However, in our study the compensatory hypertrophy that follows hemicastration (Lipschutz -1922;Liang and Liang -1970;Cunningham et al -1978;Orth et al -1984;Gerendai et al -1983) is not altered by vasectomy contralateral to the removed testis, a decrease in basal testosterone production can be observed. Since a similar decrease in basal testosterone production of the testes appears after bilateral vasectomy, it seems very likely that the decrease in steroid production in…”

Changes in Gonadotropin Secretion following Complete or Hemicastration in the Adult Rat

“…Perhaps the elevated LH levels are necessary to increase the number of interstitial cells in the remaining testis. Liang and Liang (6) found increased numbers of interstitial cells in testes of hemicastrated rats (LH levels presumably high) and decreased numbers in hemicastrates treated with testosterone cypionate (LH levels presumably low). Thus high LH levels may result in increased numbers of interstitial cells which, although not substantially increasing testis weight, might eventually be able to maintain normal rates of testosterone secretion without the necessity of con tinued high LH levels.…”