The effects of growth hormone, thyroxine and insulin on the activities of reduced nicotinamide adenine dinucleotide phosphate dehydrogenase, glucose-6-phosphatase and glycogen phosphorylase in fetal rat liver.
Growth hormone (GH), thyroxine (T4) and insulin were injected, in utero into 20.5 day-old rat fetuses to study the effects of these hormones on the activities of liver NADPH dehydrogenase, glucose-6-phosphatase and glycogen phosphorylase. It was found that at 21.5 days of gestation, GH increases the fetal liver glucose-6-phosphatase activity and decreases the liver glycogen phosphorylase activity. T4 treatment augments the activity of NADPH dehydrogenase even at 0.3% of the dose shown previously to produce premature elevation of activity. Prior to this experiment T4 in large doses has been shown to be capable of elevating glucose-6-phosphatase. However, at the lower T4 dose used, no treatment effect was observed. The fetal rat liver is responsive to insulin at 21.5 days and insulin was able to depress glucose-6-phosphatase activity. Thereby, showing that the influence of insulin on this enzyme begins prior to birth instead of just subsequent to birth.
D000818:Animals; D005260:Female; D005333:Fetus / Q000378:metabolism; D005952:Glucose-6-Phosphatase / Q000378:metabolism*; D013006:Growth Hormone / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D009252:NADPH Dehydrogenase / Q000378:metabolism*; D006005:Phosphorylases / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats; D013974:Thyroxine / Q000494:pharmacology*
D007328:Insulin; D013006:Growth Hormone; D009247:NADH, NADPH Oxidoreductases; D009252:NADPH Dehydrogenase; D006005:Phosphorylases; D005952:Glucose-6-Phosphatase; D013974:Thyroxine