NaHCO₃ and KHCO₃ ingestion rapidly increases renal electrolyte excretion in humans

Abstract

This paper describes and quantifies acute responses of the kidneys in correcting plasma volume, acid-base, and ion disturbances resulting from NaHCO(3) and KHCO(3) ingestion. Renal excretion of ions and water was studied in five men after ingestion of 3.57 mmol/kg body mass of sodium bicarbonate (NaHCO(3)) and, in a separate trial, potassium bicarbonate (KHCO(3)). Subjects had a Foley catheter inserted into the bladder and indwelling catheters placed into an antecubital vein and a brachial artery. Blood and urine were sampled in the 30-min period before, the 60-min period during, and the 210-min period after ingestion of the solutions. NaHCO(3) ingestion resulted in a rapid, transient diuresis and natriuresis. Cumulative urine output was 44 +/- 11% of ingested volume, resulting in a 555 +/- 119 ml increase in total body water at the end of the experiment. The cumulative increase (above basal levels) in renal Na(+) excretion accounted for 24 +/- 2% of ingested Na(+). In the KHCO(3) trial, arterial plasma K(+) concentration rapidly increased from 4.25 +/- 0.10 to a peak of 7.17 +/- 0.13 meq/l 140 min after the beginning of ingestion. This increase resulted in a pronounced, transient diuresis, with cumulative urine output at 270 min similar to the volume ingested, natriuresis, and a pronounced kaliuresis that was maintained until the end of the experiment. Cumulative (above basal) renal K(+) excretion at 270 min accounted for 26 +/- 5% of ingested K(+). The kidneys were important in mediating rapid corrections of substantial portions of the fluid and electrolyte disturbances resulting from ingestion of KHCO(3) and NaHCO(3) solutions.

Effect of sodium bicarbonate in an experimental model of radiocontrast nephropathy

“…13 Because free radicals are postulated to contribute acute renal failure from both ischemia and contrast, urinary alkalinization may reduce injury. 14,15 Sodium bicarbonate is found to be protective in various forms of renal injury, 16,17 but there are few experimental data on its method of action and on the potential benefit of a single prophylactic dose administrated immediately before the ischemic insult. Pretreatment with sodium bicarbonate was found to be associated with significant functional and morphological protection in ischemic rat kidney.…”

Dietary Cl−restriction upregulates pendrin expression within the apical plasma membrane of type B intercalated cells

“…Dietary intake of HCO 3 Ϫ has a variety of effects on renal function such as a transient increase in glomerular filtration rate and increased Na ϩ excretion (11). Thus pendrin protein expression may be regulated directly or indirectly through changes in intake of HCO 3 Ϫ .…”

The Pathogenesis, Outcomes, and Prevention of Contrast-Associated Acute Kidney Injury

“…The hypothesis behind employing bicarbonate (as the anion to pair with sodium) stems from its ability to alkalinize the urine and potentially inhibit free-radical formation, which occurs preferentially at acidic pHs (Halliwell and Gutteridge, 1990;Lindinger et al, 2000).…”