Hormones and liver cytoplasm. 3. Succinic dehydrogenase, nucleases and ‘polymerized’ ribonucleic acid as affected by hypophysectomy, growth-hormone treatment and adrenalectomy

Abstract

The levels of activity of succinic dehydrogenase and of nucleases in rat-liver cytoplasm were studied in relation to alterations in hormonal balance. Distribution of activity among separated fractions (mitochondria!, microsomal and supernatant fractions) was also studied. The succinic dehydrogenase activity of the whole cytoplasm and of the mitochondrial fraction rose after hypophysectomy and tended to rise after adrenalectomy. Treatment with growth hormone reversed the effect of hypophysectomy on the whole cytoplasm. Cytoplasmic deoxyribonuclease activity rose slightly after hypohysectomy (whether or not growth hormone was given), and more markedly after adrenalectomy, due partly to a rise in the activity of the supernatant fraction. The acid-ribonuclease activity of the whole cytoplasm and that of the supernatant fraction rose after hypophysectomy (whether or not growth hormone was given) and after adrenalectomy. Alkaline-ribo-nuclease activity did not alter with changes in hormonal status. The increase in the amount of ribonucleic acid in the supernatant fraction which occurs after adrenalectomy was due to a rise in "polymerized" ribonucleic acid.