Regulation of the metabolism of pituitary nucleic acids in female rats.
Ovariectomy caused an increase in the metabolism of pituitary nucleic acids. This effect was reversed in vivo by a biphasic action of oestradiol-17 beta which first facilitated RNA metabolism after 8 h and then inhibited it 16 h after intraperitoneal injection. To analyse the origin of this biphasic effect the roles of LH releasing hormone (LH-RH) and hysterectomy were examined. Incorporation of uridine into the RNA of the anterior pituitary gland of female rats was inhibited both in vivo and in vitro by LH-RH. Hysterectomy augmented the increase in the RNA metabolism caused by ovariectomy whereas steroid-free uterine extracts inhibited the increase significantly. We have concluded that extrapituitary factors may be involved in the effects of oestrogen on the metabolism of pituitary nucleic acids.
D000818:Animals; D002369:Castration; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007044:Hysterectomy; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D012313:RNA / Q000378:metabolism*; D051381:Rats; D014020:Tissue Extracts / Q000494:pharmacology; D014529:Uridine / Q000378:metabolism*
D014020:Tissue Extracts; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D012313:RNA; D014529:Uridine