The influence of unilateral castration on testicular morphology and function in adult rams.

An experiment was designed to investigate the mechanisms controlling testicular compensatory hypertrophy in rams. Endocrine and histological events were examined, with special attention to Sertoli cell hyperplasia and hypertrophy as contributing factors to the compensatory process. Fifteen sexually mature yearling Targhee rams were allotted to intact control (C, n = 5) and unilateral castrate (UC, n = 10) treatment groups in June. Approximately 150 days after UC, testicular tissue was collected in November after efferent duct cannulation and rete testis fluid (RTF) collection or perfusion fixation. Unilateral castration increased mean testis weight by 56% (p = 0.01) and mean epididymal weight by 15% (p = 0.05). Although the mean volume of RTF collected more than doubled after UC (1.55 +/- 0.86 vs. 0.63 +/- 0.10 ml for UC and C rams, respectively), the difference was not statistically significant. By 150 days after UC, the concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) in jugular venous blood did not differ between the two treatment groups. The concentrations of T. dihydrotestosterone (DHT), and androgen-binding protein (ABP) in RTF were also similar for UC and C rams. However, since the observed mean RTF volume was increased, the amounts of T, DHT, and ABP exiting the testes of these UC rams via the RTF were approximately doubled, although this difference was not statistically significant. UC increased the mean diameter of seminiferous tubules by 21% (p less than 0.01) and of their lumina by 51% (p less than 0.01), but did not significantly increase mean height of seminiferous epithelium or estimated length of seminiferous tubules per testis.(ABSTRACT TRUNCATED AT 250 WORDS)