The calcemic response to PTH in the rat: effect of elevated PTH levels and uremia

Kidney Int. 1994 Aug;46(2):310-7. doi: 10.1038/ki.1994.276.


Secondary hyperparathyroidism (2 degrees HPT) is a consistent finding in renal failure. A decreased calcemic response (CR) to parathyroid hormone (PTH) contributes to the development of 2 degrees HPT. Since parathyroidectomy (PTX) corrects the decreased CR to PTH in azotemic animals, down-regulation of PTH receptors induced by an elevation of PTH has been advanced as an important factor in the development of 2 degrees HPT. The goal of the study was to determine in azotemic rats whether a progressive reduction of PTH improves the CR to PTH and whether the maintenance of normal PTH levels corrects the CR to PTH. Seven groups of pair-fed rats were studied. Three groups of rats had normal renal function (NRF groups) and received either a high phosphorus (HPD-NRF), a moderate phosphorus (MPD-NRF), or a low phosphorus (LPD-NRF) diet. Three azotemic (NX) groups received similar diets (HPD-NX, MPD-NX and LPD-NX groups) in order to vary the magnitude of 2 degrees HPT. A PTX was performed in a fourth azotemic group (PTX-NX) to induce the complete absence of PTH. After 14 to 16 days on the maintenance diets, the CR to PTH was determined with a 48 hour infusion of 1-34 rat PTH.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / blood*
  • Down-Regulation
  • Hyperparathyroidism, Secondary / blood*
  • Hyperparathyroidism, Secondary / physiopathology
  • Kidney Failure, Chronic / blood*
  • Kidney Failure, Chronic / physiopathology
  • Male
  • Parathyroid Glands / physiology
  • Parathyroid Hormone / blood*
  • Parathyroidectomy
  • Phosphorus, Dietary / administration & dosage
  • Rats
  • Rats, Wistar
  • Uremia / blood*
  • Uremia / physiopathology


  • Parathyroid Hormone
  • Phosphorus, Dietary
  • Calcium