Regulation of renal gluconeogenesis by α-adrenergic action

1. 1. Tubule fragments isolated from kidney cortex of fed rats by collagenase treatment were incubated with 5 mM lactate. 2. 2. By use of selective α-adrenergic agonists and blocking agents it was shown that renal gluconeogenesis is stimulated through an α 1-type of adrenoceptor. 3. 3. Catecholamine stimulation of the process is not abolished by omission of extracellular Ca 2+ and is not accompanied by any change in influx of 45Ca 2+. On the other hand there is an α-adrenergic stimulation of 45Ca 2+ efflux from tubule fragments preloaded with this isotope, suggesting mobilisation of some intracellular calcium store. 4. 4. Ouabain, and removal of extracellular K +, abolish noradrenaline stimulation of gluconeogenesis suggesting that Na + and/or K + are involved in transmission of the α-adrenergic stimulus.