Effects of hormones on levels of oxidized and reduced diphosphopyridine nucleotide and triphosphopyridine nucleotide in liver and diaphragm

Abstract

Oxidized and reduced DPN and TPN contents of liver and diaphragm were determined in control, diabetic and fasting rats and in rats subjected to treatment with growth hormone, thyroxine and thiouracil. Total DPN (DPN+ + DPNH) contents of liver were markedly reduced in alloxan diabetes and after 48 hours starvation. A decrease was also found after thyroxine treatment. Striking increases were noted after treatment with one crystalline growth-hormone preparation, but not with a less active one. Total liver TPN (principally TPNH) content was strikingly reduced by thyroxine treatment, but thiouracil produced no significant change. The DPNVDPNH quotient of rat liver was significantly reduced in alloxan diabetes. Alterations in diaphragm coenzyme contents were less striking than those in liver. An attempt was made to account for the low DPN+/DPNH quotient found in diabetic liver, and it is tentatively suggested that hormones may directly or indirectly regulate the synthesis of both DPN and TPN.