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

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

The aquaporin-7 (AQP7) water channel is known to be a member of the aquaglyceroporins, which allow the rapid transport of glycerol and water. In this chapter, we review the physiological functions of AQP7 in the kidney and the male reproductive system.In the kidney, AQP7 is abundantly present at the apical membrane of the proximal straight tubules. Although the contribution of AQP7 to the water permeability of proximal straight tubules was found to be minimal compared with that of AQP1, we identified a novel glycerol reabsorption pathway that may be important for preventing glycerol from being excreted into urine.In the male reproductive system, AQP7 is present particularly in the spermatids, as well as in the testicular and epididymal spermatozoa, suggesting that AQP7 has some role in late spermatogenesis. However, male AQP7 knockout mice were not sterile, and their sperm did not show any morphological or functional abnormalities.
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PMID:Function of aquaporin-7 in the kidney and the male reproductive system. 1909 80

Expression of aquaporin water channels (AQPs) in the male excurrent ducts, is of major importance for local water movements. To study the influence of pre- and postnatal undernutrition on AQP-expression in the adult male genital tract, 4 pregnant female rats were fed ad libitum (control group) and 4 with 33.5% of gestational feed requirements (underfed group). Feeding restriction of underfed group pups continued up to weaning (25 days of age), then all pups were fed ad libitum until slaughtered at 100 days of age. Epididymides were sampled and processed for aquaporin immunohistochemistry. Expression of AQP1 was similar either in the control and underfed groups of rats, strongly evidenced at the apical and lateral plasma membrane of the efferent ducts non-ciliated cells, in the smooth muscle cells surrounding epididymal duct and in blood vessel endothelium throughout the epididymis. AQP2-immunoreactivity was present in the corpus and cauda regions, strongly expressed in the principal cells of both groups of rats. In contrast, AQP9 expression was modified by early life undernourishment, as it was weakly evidenced at the microvilli in the principal cells and strongly diminished or completely lacked in the clear cells of the cauda, in underfed group epididymides. Since it is known that clear cells are involved in luminal fluid acidification, this function might be altered in adult animals, which were underfed during early life.
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PMID:Undernutrition during foetal to prepubertal life affects aquaporin 9 but not aquaporins 1 and 2 expression in the male genital tract of adult rats. 2070 87

The process of water movement in the excurrent duct system of the male reproductive tract is pivotal for establishment of male fertility. The objective was to elucidate expression of aquaporin (AQP) water channels in the stallion reproductive tract. Real-time RT-PCR detected expression of AQP0-5 and AQP7-11 in testis, epididymis, and ductus deferens of mature stallions. There were two main expression patterns: (1) higher expression in testis than in epididymis and ductus deferens (AQP0, -4, -5, -8, -10, and -11); and (2) lower expression in testis than in epididymis and ductus deferens (AQP1, -3, -7, and -9). Overall, we inferred that fluid transport in the stallion testicle involved a collaboration of AQP subtypes (primarily AQP2, -5, -7, and -8). Based on immunohistochemistry, expression of AQP subtypes analyzed (i.e., AQP0, -2, -5, and -9) was localized to Leydig cells and elongated and round spermatids. Functional significance of AQP expression by Leydig cells remained uncertain. In elongated and round spermatids, AQP s likely contributed to the volume reduction observed during spermatogenesis. Subtypes AQP2 and AQP9 were the predominant forms expressed in epididymal tissue. Regulation of AQP2 expression, especially in the epididymal head, seemed to occur at the post-transcriptional level, as protein expression upon immunohistochemistry was pronounced, despite low transcript abundance. In epididymal tissue, AQPs likely contributed to fluid resorbtion, given their localization on the apical membrane of principal cells.
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PMID:Region-specific expression of aquaporin subtypes in equine testis, epididymis, and ductus deferens. 2371 68

Four different aquaporins (AQP1, 2, 5 and 9), integral membrane water channels that facilitate rapid passive movement of water, were immuno-localized in the excurrent ducts collected from sexually mature cats during orchiectomy. Aquaporins 1, 2 and 9, were immuno-localized at distinct levels, whereas AQP5 was undetectable all along the feline genital tract. No immunoreactivity was present at the level of the rete testis with any of the antibodies tested. In the efferent ducts, AQP1-immunoreactivity was strongly evidenced at the apical surface of the non-ciliated cells, and AQP9-immunoreactivity was shown at the periphery of both ciliated and non-ciliated cells. Aquaporins 2 was absent in the caput epididymidis, either in the efferent ducts or in the epididymal duct. Otherwise, AQP2 was increasingly localized at the adluminal surface of principal cells from the corpus to the cauda epididymidis and more weakly in the vas deferens epithelium. The supranuclear zone of the epididymal principal cells was AQP9-immunoreactive throughout the duct, with the exclusion of the vacuolated sub-region of the caput and with higher reaction intensity in the cauda region. AQP1 was present in the blood vessels all along the genital tract. AQP1 was expressed also in the smooth muscle layer of the vas deferens. The tested AQP molecules showed a different expression pattern in comparison with laboratory mammals, primates and the dog, unique other carnivore species studied to date. The present information is possibly useful in regard to the regional morphology of the feline epididymis and correlated functions, which are still a matter of debate.
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PMID:Immunolocalization of aquaporin water channels in the domestic cat male genital tract. 2382 97

The maternal nutritional status is essential to the health and well-being of the fetus. Maternal protein restriction during the perinatal stage causes sperm alterations in the offspring that are associated with epididymal dysfunctions. Vascular endothelial growth factor (VEGF) and its receptor, VEGFr-2, as well as aquaporins (AQPs) are important regulators of angiogenesis and the epididymal microenvironment and are associated with male fertility. We investigated the effects of maternal protein restriction on epididymal angiogenesis and AQP expression in the early stages of postnatal epididymal development. Pregnant rats were divided into two experimental groups that received either a normoprotein (17% protein) or low-protein diet (6% protein) during gestation and lactation. At postnatal day (PND)7 and PND14, male offspring were euthanized, the epididymides were subjected to morphometric and microvascular density analyses and to VEGF-A, VEGF-r2, AQP1 and AQP9 expression analyses. The maternal low-protein diet decreased AQP9 and VEGFr-2 expression, decreased epididymal microvascularity and altered the morphometric features of the epididymal epithelium; no changes in AQP1 expression were observed at the beginning of postnatal epididymal development. Maternal protein restriction alters microvascularization and affects molecules involved in the epidydimal microenvironment, resulting in morphometric alterations related to a delay in the beginning of epididymis postnatal development.
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PMID:Maternal Protein Restriction Modulates Angiogenesis and AQP9 Expression Leading to a Delay in Postnatal Epididymal Development in Rat. 3153 10