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- Title
Renin stimulating properties of parathyroid hormone-related peptide in the isolated perfused rat kidney.
- Authors
Saussine, Christian; Massfelder, Thierry; Parnin, Frederique; Judes, Clement; Simeoni, Umberto; Helwig, Jean-Jacques
- Abstract
Previous studies showed that PTHrP exhibits renal vasodilating, arteriolar cAMP stimulating and receptor binding properties. The present experiments were designed to study whether PTHrP may influence renin secretion. Rat kidneys were isolated and single-pass perfused at constant flow and stabilized pressure. Exposures to PTHrP or PTH stimulated a dose-dependent renin release reaching similar Vmax. The affinity (0.1 mM) and threshold concentration (0.01 mM) for PTHrP were about 10 times lower than for PTH. Compared to 10 μM isoproterenol, the maximum renin responses to PTHrP were similar but of shorter duration. The PTHrP dose-response curve was not affected by 10 μM indomethacin. Administered simultaneously, PTHrP and PTH displayed no additive effects. PTHrP-induced renin release as well as the role of extracellular calcium were further studied in nonfiltering kidneys, which were perfused at a constant flow and stable pressure in a closed circuit. Basal renin release was inversely related with perfusate calcium and was depressed by the calcium ionophore BAY-K8644. PTHrP (100 mM) induced a 1.6-fold increase of basal renin release in normocalcic perfusate. Removing calcium abolished renin responses. PTHrP reversed the inhibiting effects of hypercalcic media or BAY-K8644 on basal renin release. The results support calcium-mediated renin stimulating properties for PTHrP, via PTH receptors, independently from baroreceptors, macula densa and prostaglandins.
- Subjects
RENIN; ASPARTIC proteinases; JUXTAGLOMERULAR apparatus; PARATHYROID hormone; CALCIUM regulating hormones; KIDNEY diseases; LABORATORY rats
- Publication
Kidney International, 1993, Vol 44, Issue 4, p764
- ISSN
0085-2538
- Publication type
Article
- DOI
10.1038/ki.1993.311