Effects of chlorothiazide, furosemide and PTH on Na+ and Ca2+ handling in isolated perfused kidneys of the spontaneously hypertensive rat.
The role of the kidney in a disturbed calcium metabolism in spontaneously hypertensive rats (SHR) was investigated. The hemodynamics of isolated perfused SHR kidneys were not basically altered compared to Wistar-Kyoto (WKY) control kidneys. Renal calcium handling by isolated perfused WKY and SHR kidneys at 12 weeks of age was not significantly different. In addition, the effects of chlorothiazide and furosemide on renal calcium handling were studied in isolated perfused kidneys from both rat strains. Both diuretics increased glomerular filtration rate, diuresis and excretion of sodium and calcium. However, both diuretics stimulated diuresis and calcium excretion significantly less in SHR than in WKY kidneys. The calciuric action of chlorothiazide was completely abolished by administration of human-parathyroidhormone (hPTH), while the natriuric effect was unchanged by hPTH. This observation suggests that a hypocalciuric action of chlorothiazide 'in vivo' is possibly mediated by PTH. Our study suggests that the kidney is not responsible for the disturbance in calcium metabolism in SHR. A surprising finding is that the SHR kidney was less responsive to the diuretics furosemide and chlorothiazide than the kidney of the WKY control.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002740:Chlorothiazide / Q000494:pharmacology; D004232:Diuretics / Q000494:pharmacology*; D005665:Furosemide / Q000494:pharmacology; D006439:Hemodynamics; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D066298:In Vitro Techniques; D007668:Kidney / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D010281:Parathyroid Hormone / Q000494:pharmacology; D010477:Perfusion; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012964:Sodium / Q000378:metabolism
D004232:Diuretics; D010281:Parathyroid Hormone; D002740:Chlorothiazide; D005665:Furosemide; D012964:Sodium; D002118:Calcium