Additive effects of thyroid hormone, growth hormone and testosterone on deoxyribonucleic acid-dependent ribonucleic acid polymerase in rat-liver nuclei.

摘要: 1. The stimulations of DNA-dependent RNA polymerase in isolated rat-liver nuclei by thyroid hormone, human growth hormone and testosterone are compared. 2. Single or multiple administrations growth-promoting doses tri-iodo-l-thyronine, stimulate the Mg(2+)-activated RNA-polymerase reaction from thyroidectomized, hypophysectomized castrated rats respectively. magnitude stimulation was proportional to degree enhancement liver each hormone. After a single injection, latent period preceding 1, 2 10hr. for tri-iodothyronine time-course enzyme activity synthesis rapidly labelled nuclear vivo were also different 3. Growth administration failed Mn(2+)/ammonium sulphate-activated reaction. Thyroid testosterone, however, stimulated it but effect less pronounced occurred several hours later than that observed 4. In combination experiments, thyroidectomized given repeated at levels produced maximum activity. Taking into account second caused an additional Similar additive effects thyroidectomized-castrated after treatment with testosterone. compatible capacity promote deprived it. 5. It is concluded that, although these hormones have some similar effects, regulation may be mediated via routes