Effect of Orchiectomy on the Amino Acid Incorporation into Proteins of Anterior Pituitary and Hypothalamus of Rats

The influence of orchiectomy upon the in vivo incorporation of labeled phenylalanine into proteins of rat anterior pituitary gland, hypothalamus, and cerebral cortex has been studied. The uptake of the labeled amino acid by all the studied tissues was unaffected by orchiectomy. Three and 6 weeks after castration there was a significant increase in the sp act of hypophyseal proteins, which was restored to normal values by testosterone administration. A biphasic response to orchiectomy was observed in the hypothalamus. After 3 weeks of castration, there was a significant decrease in the sp act of proteins, while an increase occurred after 6 weeks. In both cases testosterone administration corrected these altered patterns to normal values. Castration did not affect the protein synthesis in the cerebral cortex. The changes in the protein-synthetic activity are discussed on the basis of the neuroendocrine changes produced by castration.