EFFECTS OF PARATHYROID-HORMONE ON CYCLIC-AMP, CYCLIC-GMP, AND EFFLUX OF CALCIUM IN ISOLATED RENAL TUBULES

  • 1 January 1977
    • journal article
    • research article
    • Vol. 3  (2) , 129-138
Abstract
The effects of parathyroid hormone (PTH) on concentrations of cyclic[c]AMP and cGMP were investigated in isolated renal cortical tubules from hamsters. Efflux of 45Ca from tubules was compared to temporal changes in both cyclic nucleotide concentrations. A rapid increase in cAMP occurred following addition of PTH which was maximal by 1 min but decreased over the next 4 min period. cGMP concentrations were not significantly altered at 1 min but increased between 1-5 min from basal levels. Concentrations of both nucleotides remained significantly elevated from basal levels between 5-15 min following PTH. Efflux of 45Ca was increased by PTH with time-course changes closely paralleling changes in cGMP concentrations. Changes in both cAMP and cGMP were related to PTH concentrations of the incubation media and were increased by addition of theophylline. Increasing the Ca concentration from 1 to 3 mM did not significantly alter the effect of PTH on cAMP, however, cGMP concentrations were further increased.