[Metabolic alkalosis on the surface but metabolic acidosis in depth].

Our purpose in writing this article is to emphasize the acid-base consequences and total body imbalances which follow the selective depletion of HCl. The initial body balance is an equimolar deficit of chloride and gain of bicarbonate. Within a short period of time, body balance changes; the net deficits are closer to equimolar losses of potassium and chloride.

Mechanisms of proximal proton secretion in BBM of herbivorous, omnivorous, and carnivorous species.

The mechanisms of proton secretion by the proximal brush-border membrane (BBM) were compared in carnivorous (dog), omnivorous (human, pig, rat), and herbivorous (rabbit, hamster) species. The activity of the proton pump (V-type bafilomycin-sensitive H(+)-adenosinetriphosphatase) and of the Na+/H+ exchanger (amiloride-sensitive quenching of acridine orange fluorescence), the two major proton secretion mechanisms, was measured. The enzymatic activity of the H(+)-adenosinetriphosphatase activity was measured in intact (endosomes) and solubilized (0.

Could cytoplasmic concentration gradients for sodium and ATP exist in intact renal cells?

In renal cells, the Na+ pump maintains a transmembrane concentration gradient for sodium ensuring the net reabsorption of sodium with or without cotransported species. This process requires a significant fraction of the ATP turnover of proximal tubules and thick ascending limbs. To understand the potential regulatory influences of Na+ and ATP on the activity of the Na+ pump in these nephron segments, the apparent kinetics of the membrane-bound Na+-K+ ATPase and of the cellular Na+ pump were studied in different preparations of dog proximal tubules and thick ascending limbs (tubular suspensions, tissue homogenates, and basolateral membrane vesicles) obtained from dog kidney cortex and red medulla.

Glucose metabolism in dog inner medullary collecting ducts.

The adenosine triphosphate (ATP) generating pathways of dog inner medullary collecting ducts (IMCD) were examined in vitro using suspensions of dog IMCD tubules incubated under aerobic and anaerobic conditions. Glucose is always the preferred substrate for this tissue, even if lactate can be oxidized under aerobic conditions. The metabolism of glucose proceeds largely towards lactate accumulation in the presence or absence of oxygen.

A method to evaluate renal ammoniagenesis in vivo.

A reduced rate of excretion of ammonium (NH4+) can be due to either a low rate of production and/or a low transfer of NH4+ to the urine. At present, there is no way to obtain a measure of the rate of production of NH4+ in vivo without invasive techniques. Hence, our purpose was to develop a non-invasive test to reflect this rate in vivo.