THE EFFECT OF DIFFERENT HORMONAL CONDITIONS ON THE CONCENTRATION AND OXIDOREDUCTION STATE OF THE NICOTINAMIDE NUCLEOTIDES OF RAT LIVER

Abstract

Adrenalectomy decreases the nicotinamide adenine dinucleotide phosphate (NADP+) content by 80% but has little effect on nicotinamide adenine dinucleotide (NAD+), reduced nicotinamide adenine dinucleotide (NADH), or reduced nicotinamide adenine dinucleotide phosphate (NADPH). High doses of cortisone produce similar changes, but more physiological doses (5 [mu]g daily) tend to increase the NADP+ content. Glucagon treatment of normal rats lowered the NADH and NADP+ concentrations but did not affect the total amounts present. Growth hormone increased the concentrations and total amounts of NAD+ and NADH but significantly decreased the concentrations and total amounts of NADP+ and NADPH. Measurements were made of a number of enzymes in the livers of adrenalectomized and glucagon-treated rats that could affect the oxidoreduction state of NADP. The activities of glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase are not affected by adrenalectomy or treatment with cortisone or glucagon. Nor does adrenalectomy affect the activity of NADPH-cytochrome c oxidoreductase or NADPH-gluttathione oxidoreductase. The hepatic content of glutathione is, however, decreased 50% by adrenalectomy. Measurements of the oxidation of [1-14C] glucose and [6-14C] glucose by liver slices from adrenalectomized rats showed that glucose oxidation was substantially normal, although phenazine methosulphate caused a smaller stimulation of the oxidation of C-1 of [1-14C] glucose in slices from the livers of adrenalectomized rats than it did with slices from controls. The hepatic synthesis of lipids from [1-14C] glucose was marginally increased in adrenalectomized rats. The additional NADP+ found when liver is extracted with 0[center dot]02N -sulphuric acid-0[center dot]1M -sodium sulphate is less affected than the NADP+ extracted with 0[center dot]1N-hydrochloric acid in adrenalectomized or glucagon-treated rats. Hooded Norway rats appear to have less of this extra form of this extra form of NADP+ than albino rats. An attempt was made to correlate the observed changes in the nicotinamide nucleotides with metabolic patterns prevailing in different hormonal conditions.