Ammonia excretion at the gills of fish has been studied for 80 years, but the mechanism(s) involved remain controversial. The relatively recent discovery of the ammonia-transporting function of the Rhesus (Rh) proteins, a family related to the Mep/Amt family of methyl ammonia and ammonia transporters in bacteria, yeast and plants, and the occurrence of these genes and glycosylated proteins in f...

32 33 Hagfishes are the most ancient of the extant craniates, and demonstrate a 34 high tolerance for a number of unfavorable environmental conditions including 35 elevated ammonia. Proposed mechanisms of ammonia excretion in aquatic 36 organisms include vesicular NH4+ transport and release by exocytosis in marine 37 crabs, and passive NH3 diffusion, active NH4+ transport and paracellular leaka...

The collecting duct is the primary site of urinary ammonia secretion; the current study determines whether apical ammonia transport in the mouse inner medullary collecting duct cell (mIMCD-3) occurs via nonionic diffusion or a transporter-mediated process and, if the latter, presents the characteristics of this apical ammonia transport. We used confluent cells on permeable support membranes and...

Renal ammonia metabolism is a fundamental element of acid-base homeostasis, comprising a major component of both basal and physiologically altered renal net acid excretion. Over the past several years, a fundamental change in our understanding of the mechanisms of renal epithelial cell ammonia transport has occurred, replacing the previous model which was based upon diffusion equilibrium for NH...

17β-estradiol (E2), the predominant and most biologically active form of estrogen has been shown to modulate various macrophage activities, sometimes with opposite effects, related to experimental conditions. The aim of this study was to investigate the effect of E2 alone or in combination with PKA inhibitor H-89 or recombinant human chorionic gonadotropin (rhCG) on leishmanicidal activity and ...

Dietary protein restriction has multiple benefits in kidney disease. Because protein intake is a major determinant of endogenous acid production, it is important that net acid excretion change in parallel during protein restriction. Ammonia is the primary component of net acid excretion, and inappropriate ammonia excretion can lead to negative nitrogen balance. Accordingly, we examined ammonia ...

Lithium therapy's most common side effects affecting the kidney are nephrogenic diabetes insipidus (NDI) and chronic kidney disease. Lithium may also induce a distal renal tubular acidosis. This study investigated the effect of chronic lithium exposure on renal acid-base homeostasis, with emphasis on ammonia and citrate excretion. We compared 11 individuals on long-term lithium therapy with six...