Testicular Compensatory Hypertrophy Related to Hemicastration in Prepubertal Dogs

Abstract

Several studies have reported that the plasma testosterone (T) level and semen volume are compensated after hemicastration (HEC) in adult dogs, but that the sperm count is not. Nevertheless, the effects of HEC in prepubertal dogs have not been reported. In this study, HEC was performed at 16 weeks of age in 8 male beagles, and the function of the residual testis was investigated until 48 weeks of age. The testis volume was consistently higher in the HEC group than the control (CON) group. After 40 weeks of age, compensatory hypertrophy was observed, with a mean testis volume of 125% of that in the CON group (p<0.05). Furthermore, the semen volume and plasma testosterone (T) level were similar to those in the CON group, suggesting functional compensation, but the sperm count was not compensated. These results showed that the testis volume, semen volume, and plasma T level were compensated after HEC in prepubertal dogs, but the spermatogenic function was not.

Effect of vitamin E on oxidative stress in the contralateral testis of neonatal and pubertal hemicastrated rats

“…In the initial stages of CTH, an increased number of Sertoli cells results from elevated levels of follicle-stimulating hormone [6]. This is followed by testicular enlargement and increased numbers of Leydig cells; however, an elevation of testosterone is not detected [6].…”

“…It has been well documented that unilateral castration of sexually immature animals results in hypertrophy of the contralateral testis [4,5,6]. In the initial stages of CTH, an increased number of Sertoli cells results from elevated levels of follicle-stimulating hormone [6].…”

“…In the initial stages of CTH, an increased number of Sertoli cells results from elevated levels of follicle-stimulating hormone [6]. This is followed by testicular enlargement and increased numbers of Leydig cells; however, an elevation of testosterone is not detected [6]. Several studies examining the hormonal aspects of CTH have been conducted using prepubertal rats and have reported increased levels of follicle-stimulating hormone [1].…”

“…Several studies examining the hormonal aspects of CTH have been conducted using prepubertal rats and have reported increased levels of follicle-stimulating hormone [1]. Despite increased testicular volume, CTH does not seem to improve the quality of semen [6]. Furthermore, studies conducted on animal models show that the quantity and motility of sperm are significantly reduced relative to non-CTH controls [2].…”

“…Previous studies have shown that the unilateral castration of immature animals results in compensatory hypertrophy of the remaining testis [1,2,3,4,5,6]. CTH is the result of the increased size and number of germ cells, as well as increased size of Sertoli cells [3], and of oversecretion of gonadotropins [2,3,4,5,6].…”