Changes in (3H)leucine incorporation into pineal proteins following estradiol or testosterone administration: involvement of the sympathetic superior cervical ganglion.

Pineal denervation by superior cervical ganglionectomy (Gx) decreased high affinity binding of estradiol (E2) to the pineal cytosol of female rats and of testosterone to the cytosol of male rats by 40 and 26% and by 75 and 80%, 5 and 14 days after sugery; hormone binding remained unchanged up to 24 h after surgery. Binding to the nuclear fraction decreased sigificantly by 2 weeks after incorporation of (3H) leucine into pineal proteins in Gx. A single injection of E2 (mug) to testosterone propionate (TP) (500 mug) failed to increase the Gx rats when injected 1 or 5 days after surgery. Significant increases were observed in sham-operated controls or in rats subjected to bilateral decentralization of ganglia; however on the 5th day an impairment was observed in hormone ability to enhance [3H]leucine incorporation in decentralized rats. The administration of isoproterenol 19 and 3 h before sacrifice replenished pineal-binding sites for E2 and testosterone in Gx rats, but failed to restore the responsiveness of denervated pineals to hormone administration. Moreover, E2 or TP treatment blocked the increase in labeled amino acid incorporation into proteins brought about by isoproterenol per se. The administration of propranolol 2 and 7 h after hormone injection decreased the ability of E2 and TP to enhance [3H]leucine incorporation by 55 and 41%, respectively. Tyrosine hydroxylase activity of the superior cervical ganglia decreased by 36 and 41% 6 h after E2 or TP administration, and by 43 and 47% after 3 daily injections of the hormones, whereas pineal tyrosine hydroxylase remained unchanged. Hormone treatment for 3 days increased the in vitro uptake of norepinephrine by the ganglia but did not affect uptake in the pineal gland. These data indicate that the integrity of neurons of the superior cervical ganglia is an absolute requirement for E2 and testosterone to enhance [3H]leucine incorporation into pineal proteins in rats.