ABSTRACT
The effects of the dibutyryl derivatives of cyclic GMP and cyclic AMP on lactic acid and steroid production were compared in intact mouse adrenal glands at concentrations of 0·5–1 mmol/l and in mouse adrenal cell suspensions at concentrations of 0·01–1 mmol/l. The dibutyryl derivative of cyclic GMP had little or no effect on lactic acid production in either tissue preparation. It caused a slight stimulation of corticosteroid output in intact glands at a concentration of 1 mmol/l, amounting to one-tenth of the response observed with 1 mm-dibutyryl cyclic AMP. Dose-dependent increases in lactic acid and steroid production were obtained with dibutyryl cyclic AMP in cell suspensions. AMP and GMP increased lactic acid but not steroid production.
All the substrates tested (glucose, glucose-6-phosphate, fructose, fructose-6-phosphate, fructose-1,6-diphosphate, 10 mmol/l; pyruvate and glycerol, 20 mmol/l) stimulated basal glycolysis in intact glands and cell suspensions and none affected basal steroid production significantly. By far the greatest increase in lactic acid production was noted with fructose-1,6-diphosphate. However, only glucose and, in unsectioned glands, pyruvate exerted a potentiating effect on the glycolytic response to ACTH. Glucose potentiated the steroidogenic response to ACTH also, but only in intact glands.
The relative ineffectiveness of dibutyryl cyclic GMP is in accord with the species-dependent differing responses to the free form of the cyclic nucleotides noted in mouse and rat adrenal glands. The substrate requirements are in keeping with a rate-limiting role of phosphofructokinase and an action of ACTH at some site between the entry of glucose into the cell and the formation of fructose-1,6-diphosphate.
J. Endocr. (1985) 104, 105–111
