Increased renal tubular Na-K-ATPase activity in Milan hypertensive rats in the prehypertensive period

• Published in: Pediatric nephrology (Berlin, West) West), 1991-11, Vol.5 (6), p.700-703
• Main Authors: MELZI, M. L, SYREN, M. L, ASSAEL, B. M, SERENI, F, APERIA, A
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Blood Pressure; Ca(2+) Mg(2+)-ATPase - metabolism; Hypertension, Renal - enzymology; Hypertension, Renal - physiopathology; Kidney Tubules - enzymology; Kidney Tubules, Distal - enzymology; Kidney Tubules, Proximal - enzymology; Male; Medical sciences; Nephrology. Urinary tract diseases; Nephropathies. Renovascular diseases. Renal failure; Rats; Rats, Inbred Strains; Renovascular diseases; Sodium-Potassium-Exchanging ATPase - metabolism; Sodium-Potassium-Exchanging ATPase - physiology
• ISSN: 0931-041X; 1432-198X
• DOI: 10.1007/BF00857877

Milan hypertensive (MSH) rats develop hypertension around the 3rd-4th week of life and exhibit increased Na-pump activity in adulthood. The present study was performed to evaluate whether or not hypertension is preceded by an increase in Na-K-ATPase activity. Total and ouabain-sensitive ATPase activities were studied in single microdissected medullary thick ascending limb of Henle (mTAL) tubules from MHS, Milan normotensive (MNS) and Sprague-Dawley (SD) rats at 22-24, 26-28 and 45-60 days of age. Data are given as mean +/- SEM. Total and Na-K-ATPase activity exhibited a developmental pattern in MHS, MNS and SD rats. At 22-24 days no difference was seen between MHS and MNS animals. At 26-28 days MHS had a higher total and Na-K-ATPase activity than MNS (3031 + 171 vs 2471 + 178 pmol phosphate/mm tubule per hour, P less than 0.05; 2289 + 205 vs 1653 + 151, n = 10, P less than 0.05). At this age there was still no difference in mean arterial blood pressure (88 + 4 vs 86 + 3 mm Hg, n = 15). Adult MHS rats had higher blood pressure (140 + 9 vs 112 + 8 mm Hg, P less than 0.001) and higher total (3544 + 136 vs 2718 + 215 pmol phosphate/mm tubule per hour, n = 10, P less than 0.01) and Na-K-ATPase activity (2670 + 99 vs 1942 + 217 pmol phosphate/mm tubule per hour, n = 10, P less than 0.05) than adult MNS rats.