Urinary excretions of protein and amino acids were measured before and after exposure of rats to inhalation of nickel carbonyl in LD40 dosage. Urinary excretion of total protein was increased by an average of 2.4-fold on the first day after exposure and remained elevated (2.0-fold and 1.9-fold) on the second and third days. Urinary excretions of 16 neutral or basic amino acids were all increase...

BACKGROUND Advanced chronic kidney disease (CKD) is associated with the development of renal metabolic acidosis. Metabolic acidosis per se may represent a trigger for progression of CKD. Renal acidosis of CKD is characterized by low urinary ammonium excretion with preserved urinary acidification indicating a defect in renal ammoniagenesis, ammonia excretion or both. The underlying molecular mec...

Increased environmental pH decreases ammonia transport through the gills, impairing nitrogenous waste. The consequent toxicity is usually drastic to most fishes. A few species are able to synthesize urea as a way to detoxify plasma ammonia. We studied three teleosts of the family Erythrinidae living in distinct environments, and assumed the biochemical behaviors would be different in spite of t...

Chronic metabolic acidosis induces dramatic increases in net acid excretion that are predominantly due to increases in urinary ammonia excretion. The current study examines whether this increase is associated with changes in the expression of the renal ammonia transporter family members, Rh B glycoprotein (Rhbg) and Rh C glycoprotein (Rhcg). Chronic metabolic acidosis was induced in Sprague-Daw...

Rh C glycoprotein (Rhcg) is an NH(3)-specific transporter expressed in both intercalated cells (IC) and principal cells (PC) in the renal collecting duct. Recent studies show that deletion of Rhcg from both intercalated and principal cells inhibits both basal and acidosis-stimulated renal ammonia excretion. The purpose of the current studies was to better understand the specific role of Rhcg ex...

The Amazonian oscar is extremely resistant to hypoxia, and tolerance scales with size. Overall, ionoregulatory responses of small ( approximately 15 g) and large oscars ( approximately 200 g) to hypoxia were qualitatively similar, but the latter were more effective. Large oscars exhibited a rapid reduction in unidirectional Na(+) uptake rate at the gills during acute hypoxia (Po(2) approximatel...

Under cold acclimated conditions, goldfish (Carassius auratus) express an interlamellar cell mass (ILCM) which limits diffusive ion loss but may also impede branchial ammonia excretion (J(amm)). In the present study, goldfish were subjected to a 2-week 5 or 25 °C acclimation in order to modulate the degree of ILCM gill coverage and determine potential effects on J(amm). 25 °C-fish displayed gil...

Although aquatic animals are generally believed to export nitrogenous waste by diffusion of NH(3) or NH(4)(+) across external epithelia, evidence for active ammonia excretion has been found in a number of species. In the euryhaline green shore crab Carcinus maenas, active excretion of ammonia across isolated gills is reduced by inhibitors of the Na(+)/K(+)-ATPase and vacuolar-type H(+)-ATPase. ...