Metabolic effects of unilateral orchiectomy on the guinea pig testis.

Six months after unilateral orchiectomy, there was a significant increase in the RNA and DNA content of contralateral testes as compared with the testes of age-matched normal guinea pigs. The ratio of RNA to DNA was not affected by orchiectomy, suggesting that the compensatory growth was secondary to hyperplasia rather than hypertrophy. Tritiated thymidine uptake by the contralateral testis was elevated at 2 weeks and 2,4 and 6 months after orchiectomy, confirming that increased metabolic activity occurred in the remaining testis after hemicastration.