Acute Effects of Hydrocortisone on Gluconeogenesis from ¹⁴C- and ³H-Labeled Substrates in Intact Rats

Abstract

At short time intervals (2 and 4 hr) after a single intraperitoneal injection of hydrocortisone (20 mg/rat), gluconeogenesis was studied by intraperitoneal injection in trace amount of one of the following pairs of compounds: DL-lactate-2-¹⁴C, DL-lactate-2-3H; DL-malate- 3-¹⁴C, DL-malate-2-³H; succinate-2,2′-¹⁴C, succinate-2,2′-³H; or glycerol-l,3-¹⁴C, glycerol- 2-3^H. Conversion of radioactivity to CO₂, blood glucose and liver glycogen was measured. With all ¹⁴C-labeled substrates there was no marked change of ¹⁴CO₂ after hydrocortisone. Incorporation of both ¹⁴C and ³H from lactate and malate into glucose and glycogen was increased slightly at 2 hr and increased significantly at 4 hr after hydrocortisone. There was no change in incorporation of ¹⁴C or ³H from succinate or glycerol. Transfer of ³H from lactate and malate to glucose was somewhat more stimulated than was that of ¹⁴C. The observed changes in gluconeogenesis from certain of the labeled substrates are qualitatively similar, but less extensive, than those noted earlier with long-term administration of cortisone. (Endocrinology80: 1062, 1967)