Soluble adenylyl cyclase (sAC) represents a novel form of mammalian adenylyl cyclase structurally, molecularly, and biochemically distinct from the G protein-regulated, transmembrane adenylyl cyclases (tmACs). sAC possesses no transmembrane domains and is insensitive to classic modulators of tmACs, such as heterotrimeric G proteins and P site ligands. Thus, sAC defines an independently regulate...

PEARSON, TERRY W., AND ANDREW M. GOLDNER. Calcium transport across avian uterus. I. E$Ects of electro&e substitution. Am. J. Physiol. 225(6) : 1508-l 5 12. 1973.-Unidirectional calcium fluxes from serosa to mucosa (JS,, ) and mucosa to serosa (Jmds ) were determined across the isolated quail uterus. When the tissue was bathed with normal bicarbonate buffer, the spontaneous electrical potential ...

Using ion-exchange resins, a multiple-unit type of oral floating dosage system has been prepared to prolong gastric emptying time of dosage form. The system is composed of beads of drug-resin complex, which are loaded with bicarbonate ions and coated with a hydrophobic polymer. The system is so designed that when the beads reach the stomach, chloride ions are exchanged with bicarbonate and drug...

Rod intracellular pH (pHi) in the intact frog retina was measured fluorometrically with the dye 2',7'-bis(2-carboxyethyl)-5(and-6)-carboxyfluorescein under treatments chosen to affect putative pH-regulating transport mechanisms in the plasma membrane. The purpose was to relate possible pHi changes to previously reported effects on photoresponses. In nominally bicarbonate-free Ringer, applicatio...

Using a constant perfusion technique, sodium and bicarbonate absorption was studied in human subjects. The following observations were made on sodium absorption from saline solution: (a) the rate of sodium absorption is markedly influenced by bulk water flow, (b) when net water flow is zero, sodium absorption is zero if there are no concentration gradients between plasma and lumen that favor ne...

We previously reported that rabbit renal cortical collecting tubules can secrete bicarbonate in vitro (i.e., there can be net transport from bath to lumen, causing the concentration in the lumen to increase). Net bicarbonate secretion was observed most often when rabbits had been pretreated with NaHCO(3) and were excreting alkaline urine before being killed for experiments. The purpose of the p...

1. The PCO2 gradient between alkaline urine and arterial blood (U-B PCO2) is thought to depend primarily on distal hydrogen ion secretion. However, other variables affecting the U-B PCO2 include the urine flow rate, the urinary bicarbonate and phosphate excretion rates and the glomerular filtration rate. 2. In order to evaluate the effects of acute changes in these factors on the U-B PCO2, bica...

Glutamate in unusual places lutamate has a critical physiological function unrelated to its job as a neurotransmitter, according to results from M.M. Reddy and Paul Quinton (University of California, San Diego, CA). The duo find that glutamate activates an epithelial ion channel that is mutated in patients with cystic fibrosis. Cystic fibrosis is caused by mutations in the CFTR anion channel, w...

Isolated, surviving sacs of everted small intestine were used to characterize ammonia transport in the golden hamster. Jejunal and ileal sacs incubated aerobically in ammonia-free test solution liberated the same quantity of ammonia as did sacs that were filled and immediately emptied of their contents, indicating no significant evolution of metabolic ammonia. Under aerobic conditions, ileal sa...