The primary mechanism by which the kidneys mediate net acid excretion is through ammonia metabolism. In the current study, we examined whether chronic metabolic acidosis, which increases ammonia metabolism, alters the cell-specific and/or the subcellular expression of the ammonia transporter family member, Rhcg, in the outer medullary collecting duct in the inner stripe (OMCDi). Chronic metabol...

Ammonia metabolism is important in multiple aspects of gastrointestinal physiology, but the mechanisms of ammonia transport in the gastrointestinal tract remain incompletely defined. The present study examines expression of the ammonia transporter family members Rh B glycoprotein (RhBG) and Rh C glycoprotein (RhCG) in the mouse gastrointestinal tract. Real-time RT-PCR amplification and immunobl...

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 Rhesus factor protein, Rh C glycoprotein (Rhcg), is an ammonia transporter whose expression in the collecting duct is necessary for normal ammonia excretion both in basal conditions and in response to metabolic acidosis. Hypokalemia is a common clinical condition associated with increased renal ammonia excretion. In contrast to basal conditions and metabolic acidosis, increased ammonia excr...

Lee HW, Verlander JW, Handlogten ME, Han KH, Weiner ID. Effect of collecting duct-specific deletion of both Rh B Glycoprotein (Rhbg) and Rh C Glycoprotein (Rhcg) on renal response to metabolic acidosis. Am J Physiol Renal Physiol 306: F389–F400, 2014. First published December 11, 2013; doi:10.1152/ajprenal.00176.2013.— The Rhesus (Rh) glycoproteins, Rh B and Rh C Glycoprotein (Rhbg and Rhcg, re...

Rhesus glycoprotein homologs RhAG, RhBG, and RhCG comprise a recently identified branch of the Mep/Amt ammonia transporter family. Animal studies have shown that RhBG and RhCG are present in the kidney distal tubules. Studies in mouse and rat tissue suggest a basolateral localization for RhBG in cells of the distal tubules including the alpha-intercalated cells (alpha-IC), but no localization o...

A family of gas-transporting proteins, the Mep/Amt/Rh glycoprotein family, has been identified recently. These are integral membrane proteins, are widely expressed in sites of gas transport, and are known to transport the gaseous molecule, NH(3), and recent evidence indicates they can transport CO(2). Because the mammalian lung is a critical site for gas transport, the current studies examine t...

The erythrocyte Rh-associated glycoprotein (RhAG) was recently found to mediate transport of ammonia/ammonium when expressed in Xenopus laevis oocytes and yeast Saccharomyces cerevisiae. Nonerythroid homologs, RhBG and RhCG, are expressed in the mammalian kidney connecting segment and the collecting duct, major sites of urinary ammonia secretion. This study characterizes the transport propertie...

Chorionic gonadotropin (CG) is a glycoprotein hormone, whose action is mediated by the luteinizing hormone/CG receptor. Testosterone concentrations from six pituitary-desensitized, healthy male volunteers were obtained after four different administrations of recombinant-human CG (rhCG). We present a modeling study to provide a possible explanation for the observations that increased exposure to...

BACKGROUND The evaluation of prepubertal gonadal Leydig cells secretion requires gonadotropin stimulation. Urinary hCG (human chorionic gonadotropin) is currently unavailable in many countries, however, recombinant hCG (rhCG) can be used. Our aim was to evaluate rhCG-stimulated testicular hormones in a group of patients with cryptorchidism. METHODS We evaluated 31 prepubertal boys (age range,...