Biomaterial Database

Effect of chronic metabolic acidosis on renal growth and renal sodium handling in uninephrectomized rats. 1999

L F Menegon, and J F Figueiredo, and J A Gontijo

Departmento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, SP, Brasil.

Paucity studies have indicated that a systemic metabolic acidosis cause a decrease in salt and water reabsorption in the kidney. The following study was undertaken on male Wistar-Hannover rats (200-250 g) to investigate the effects of a chronic, NH4Cl-induced metabolic acidosis on the renal handling of Na+ in sham-operated and uninephrectomized rats, by lithium clearance. The present study shows that chronic acidosis (blood pH, 7.16 +/- 0.13) caused a sustained increase in renal fractional Na+ excretion (267.9 +/- 36.4%), accompanied by a rise in the fractional proximal (113.3 +/- 3.6%) and post-proximal (179.7 +/- 20.2%) Na+ and fractional K+ (163.4 +/- 5.6%) excretions when compared to pair-fed rats. These differences occurred in spite of an unchanged creatinine clearance and Na+ filtered load. On the other hand, a body growth impairment was observed in the acidotic (control, 258 +/- 3.7 g versus acidotic, 232 +/- 4.6 g) and pair-fed rats (225 +/- 3.6 g), whereas there was significant enhance in the kidney weights in acidotic rats (1.73 +/- 0.05 g) compared to other experimental groups (control, 1.46 +/- 0.05 g; pair-fed, 1.4 +/- 0.05 g). The renal growth indexes after metabolic acidosis NH4Cl-induced did not shown statistical difference at 1.5, 3.0 and 12 hours after uninephrectomy when were compared with pair-fed groups. However, from the fifth to tenth day after unilateral nephrectomy the renal growth index of acidotic group was significantly greater than pair-fed groups. Unilateral nephrectomy in acidotic animals caused a striking additional but transient increase in fractional renal sodium (FENa+) and potassium (FEK+) excretion from 1.5 to 3 hours post-surgery meanly associated with an enhanced post-proximal sodium excretion when compared to pair-fed uninephrectomized rats. By the fifth postoperative day the all functional values returned to baseline levels. This altered renal Na+ handling and K+ excretion may result from a reciprocal relationship between tubular metabolic pathway stimuli and ion transport. Further studies are required to investigate the acidosis involvement on functional kidney response.

UI	MeSH Term	Description	Entries
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D007684	Kidney Tubules	Long convoluted tubules in the nephrons. They collect filtrate from blood passing through the KIDNEY GLOMERULUS and process this filtrate into URINE. Each renal tubule consists of a BOWMAN CAPSULE; PROXIMAL KIDNEY TUBULE; LOOP OF HENLE; DISTAL KIDNEY TUBULE; and KIDNEY COLLECTING DUCT leading to the central cavity of the kidney (KIDNEY PELVIS) that connects to the URETER.	Kidney Tubule,Tubule, Kidney,Tubules, Kidney
D008297	Male		Males
D009392	Nephrectomy	Excision of kidney.	Heminephrectomy,Heminephrectomies,Nephrectomies
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D000141	Acidosis, Renal Tubular	A group of genetic disorders of the KIDNEY TUBULES characterized by the accumulation of metabolically produced acids with elevated plasma chloride, hyperchloremic metabolic ACIDOSIS. Defective renal acidification of URINE (proximal tubules) or low renal acid excretion (distal tubules) can lead to complications such as HYPOKALEMIA, hypercalcinuria with NEPHROLITHIASIS and NEPHROCALCINOSIS, and RICKETS.	Renal Tubular Acidosis,Renal Tubular Acidosis, Type I,Renal Tubular Acidosis, Type II,Type I Renal Tubular Acidosis,Type II Renal Tubular Acidosis,Acidosis, Renal Tubular, Type I,Acidosis, Renal Tubular, Type II,Autosomal Dominant Distal Renal Tubular Acidosis,Classic Distal Renal Tubular Acidosis,Distal Renal Tubular Acidosis,Proximal Renal Tubular Acidosis,RTA, Classic Type,RTA, Distal Type, Autosomal Dominant,RTA, Gradient Type,RTA, Proximal Type,Renal Tubular Acidosis 1,Renal Tubular Acidosis I,Renal Tubular Acidosis II,Renal Tubular Acidosis, Distal, Autosomal Dominant,Renal Tubular Acidosis, Proximal,Renal Tubular Acidosis, Proximal, with Ocular Abnormalities,Classic Type RTA,Classic Type RTAs,Gradient Type RTA,Gradient Type RTAs,Proximal Type RTA,Proximal Type RTAs,RTAs, Classic Type,RTAs, Gradient Type,RTAs, Proximal Type
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23
D017208	Rats, Wistar	A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.	Wistar Rat,Rat, Wistar,Wistar Rats