Impaired renal response to parathyroid hormone in potassium depletion.
In potassium depletion, a possible alteration of the proximal tubular response to parathyroid hormone (PTH) was evaluated in rat kidney. 1) There were impairments of both phosphaturic and urinary cyclic AMP responses to PTH. The site of the impairment was further investigated by studying the PTH-dependent cycle AMP system in renal cortex. 2) There was a lesser increase of cyclic AMP concentration by PTH in potassium-depleted slices, indicating the lesser urinary cyclic AMP was due to the specific impairment of PTH-dependent cyclic AMP in the kidney. 3). The activation of adenylate cyclase by PTH was impaired , but phosphodiesterase activity was not affected by potassium depletion, indicating the impairment of cyclic AMP generation  was due to inhibition of adenylate cyclase. 4) The  phosphaturic response to dibutyryl cyclic AMP infusion was also significantly less in the potassium-depleted animals, indicating the step subsquent to the cyclic AMP generation  is also impaired. All above results indicate that, in potassium depletion, the renal response to PTH is impaired, and the impairment is both within the step of cyclic AMP generation and after the cyclic AMP generation.
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001835:Body Weight; D003994:Bucladesine / Q000494:pharmacology; D000242:Cyclic AMP / Q000652:urine*; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000201:enzymology; D007687:Kidney Tubules, Proximal / Q000502:physiology*; D009206:Myocardium / Q000378:metabolism; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010710:Phosphates / Q000652:urine*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011188:Potassium / Q000097:blood / Q000378:metabolism; D011191:Potassium Deficiency; D051381:Rats
D010281:Parathyroid Hormone; D010710:Phosphates; D003994:Bucladesine; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases; D000262:Adenylyl Cyclases; D011188:Potassium