Incorporation of Η-Leucine into Proteins in the Hypothalamus and the Anterior Hypophysis. Effects of Pinealectomy, Superior Cervical Ganglionectomy and Continuous Exposure to Light or Darkness
Pinealectomy increased the incorporationof 3H-leucine into proteins in the hypothalamus of male rats subjected to surgery 5, 14, or 21 days earlier by 29–49%. No effects were observed within 24 h after cervical ganglia pinealectomy nor at any studied time in the adenohypo-physis. Superior cervical ganglionectomy or exposure of rats to continuous light or darkness for 14 days also resulted in significant increases in hypothalamic protein synthesis. Pinealectomy potentiated the stimulation of protein synthesis brought about by exposing rats to a continuous lighting environment. The administration of norepinephrine to sympathectomized rats reversed the ganglionectomy-induced stimulation of hypothalamic protein synthesis. Norepinephrine failed to exhibit significant effects in sham-operated controls or in ganglion-ectomized-pinealectomized rats, indicating that a denervated pineal is required in order for the catecholamine to exert its effects on hypothalamic protein synthesis.