Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Acid secretion by the rat cauda epididymidis was studied by microperfusion of the epididymal duct and by measuring the pH of the perfusate at a constant pCO(2) using a micro pH sensitive electrode. The rate of acidification was expressed as the rate of fall of intraluminal bicarbonate per cm duct per min.2. When the cauda epididymal duct was perfused with normal bicarbonate solution, the luminal bicarbonate concentration fell at a rate of 0.59 +/- 0.39 n-equiv cm(-1) min(-1) (mean +/- s.e.,n = 22).3. The rate of luminal acidification was independent of the perfusion rate but was dependent on the concentration of bicarbonate in the perfusion fluid. The rate of fall of luminal bicarbonate increased with increasing bicarbonate concentration and showed saturation at an intraluminal bicarbonate concentration of 25 m-mole/l.4. Acidification was abolished in the absence of intraluminal sodium ions. This may suggest a linked sodium reabsorption and hydrogen ion secretion.5. Acidification of the luminal fluid was studied under different acid-base conditions. In animals undergoing metabolic acidosis, the rate of acidification was enhanced, and conversely in animals undergoing metabolic alkalosis, the rate was depressed.6. Intravenous infusion of acetazolamide into rats at a dose rate of 20 mg/kg.hr markedly inhibited the acidification process. This effect was still observed in animals undergoing metabolic acidosis. Acetazolamide (10(-5)m) applied luminally was found to have no effect but higher concentration (10(-4)m) was found to inhibit acidification by 50%.7. The role of acidification of the epididymal fluid in sperm maturation was discussed.
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PMID:Luminal acidification by the perfused rat cauda epididymidis. 725 73

Acetazolamide (Ace) is a putative inhibitor of carbonic anhydrase (CA), an enzyme that catalyzes the equilibration of carbon dioxide and carbonic acid and plays a key role in HCO(3)(-) and water reabsorption and acid secretion. Aquaporins (AQPs) are channel-forming membrane glycoproteins that mediate water reabsorption by the renal tubules and other organs of mammals. AQP1 and CAII or CAIV share many common biological properties. Previous studies have shown that AQP1 and CA are located at the same sites in cells of the male reproductive tract. In the present study, Ace at a dose of 40 mg/kg/d x 14, administered per os, suppressed AQP1 gene expression and inhibited CA activity in rat testis. On day 7 of treatment the epididymal sperm motility was significantly reduced, while on day 14 a decrease in sperm count occurred. Ace caused a marked downregulation of AQP1 gene expression; significant suppression occurred on days 7 and 14. Moreover, CA activity was totally blocked throughout the treatment period. The present findings suggest that the reduction of rat sperm motility and count by Ace can be attributed to its capacity to downregulate AQP1 water channel gene expression.
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PMID:Influence of acetazolamide on AQP1 gene expression in testis and on sperm count/motility in epididymis of rats. 1213 89