Distribution of enzymes of adenylate and guanylate nucleotide metabolism in rat nephron

Cole, Barbara R.; Hays, A E; Boylan, John G.; Burch, Helen B.; Lowry, Oliver H.

doi:10.1152/ajprenal.1982.243.4.f349

Cited by 6 publications

(6 citation statements)

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“…In collecting ducts, cortical collecting ducts had the highest activities and this pattern was compatible with the results from mouse nephron [8]. As summarized in figure I, this distribution pattern was somewhat different from the previ ous study by Cole et al [13] that reported the relatively low er activities in proximal segments. This difference may be due to the different sample preparation and assaying proce dures.…”

Section: Discussionsupporting

confidence: 86%

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Localization of Low-K<sub>M</sub> cAMP Phosphodiesterase in Rat Nephron Segments

Yokoyama¹,

Takeda²,

Homma³

et al. 1997

Kidney Blood Press Res

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To evaluate the roles of cAMP degradation on hormonal actions in the kidney, we examined the segmental distribution and activities of cAMP-phosphodiesterase (PDE), a key enzyme for cAMP hydrolysis, in dissected segments of the rat nephron and characterized the isozyme compositions with subtype-specific inhibitors. Summary of the nephron distribution of PDE activities showed that cAMP-PDE activities were detected in all nephron segments and the distal convoluted tubules (DCTs) had the highest activity. Both in proximal convoluted tubules (PCTs) and medullary collecting ducts (MCDs), more than 80% of the total cAMP-PDE activities were inhibited by a nonspecific PDE inhibitor, 3-isobutyl-1-methylxanthine (IBMX). In PCTs, rolipram (type-IV PDE inhibitor) was an equally potent inhibitor of IBMX, while 8-methoxymethyl-IBMX (MM-IBMX, type-I PDE inhibitor) and cilostamide (type-III PDE inhibitor) inhibited cAMP-PDE by 35 and 57%, respectively. In MCDs, inhibition by rolipram (40%) was less than that by MM-IBMX (70%) or cilostamide (66%). Rolipram potentiated the parathyroid hormone (PTH)-induced cAMP content in PCTs most effectively. Rolipram and MM-IBMX increased the vasopressin (AVP)-stimulated cAMP content equally in MCDs. Cilostamide had no effect on the cAMP content stimulated by PTH or AVP in PCTs and MCDs. These results indicate that PDE activities were unevenly distributed along the rat nephron and cAMP-PDE was composed of at least three isoforms, namely type I, III and IV in PCTs and MCDs. Among these, type-IV PDE was responsible for hydrolysis of cAMP in PCTs, and type-I and IV PDE were responsible for that in MCDs.

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Section: Discussionsupporting

confidence: 86%

“…On the other hand Cole etal. [13] used a high concentration of cAMP with the purpose of measur ing both low-and high-Km cAMP-PDE activities.…”

Section: Discussionmentioning

confidence: 99%

Localization of Low-K<sub>M</sub> cAMP Phosphodiesterase in Rat Nephron Segments

Yokoyama¹,

Takeda²,

Homma³

et al. 1997

Kidney Blood Press Res

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“…It has a high level of expression in the kidney [26], where it is the most documented ectonucleotidase. Cole et al [6] were the first to report high ecto-5′-nucleotidase activities in rat proximal tubule. Subsequently, a comprehensive mapping of the enzyme protein in the kidney has been performed by Kaissling's group, and more recently by Vekaria et al , using immunohistochemical techniques.…”

Section: Ecto-5′-nucleotidasementioning

confidence: 99%

“…5 Distribution of ectonucleotidases along the rat nephron. Information compiled from Cole et al [6], Kishore et al [22], Vekaria et al [23], Gandhi et al [27], and Le Hir and Kaissling [28,29]. Adapted, with permission, from Vekaria et al [23].…”

Section: Ntpdase3mentioning

confidence: 99%

“…The other phosphorylating enzymes, adenylate kinases, will either catalyse the production of ADP from ATP and AMP or vice versa, depending on the concentrations of the respective nucleotides; thus: ATP + AMP ⇆ 2ADP. Adenylate kinase activity has been documented in the glomerulus, proximal convoluted tubule, thick ascending limb of Henle and distal tubule [6], though it was not possible to distinguish between intracellular and extracellular activity.…”

Section: Introductionmentioning

confidence: 99%

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Ectonucleotidases in the kidney

Shirley

Vekaria

Sévigny

2009

Purinergic Signalling

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Members of all four families of ectonucleotidases, namely ectonucleoside triphosphate diphosphohydrolases (NTPDases), ectonucleotide pyrophosphatase/ phosphodiesterases (NPPs), ecto-5′-nucleotidase and alkaline phosphatases, have been identified in the renal vasculature and/or tubular structures. In rats and mice, NTPDase1, which hydrolyses ATP through to AMP, is prominent throughout most of the renal vasculature and is also present in the thin ascending limb of Henle and medullary collecting duct. NTPDase2 and NTPDase3, which both prefer ATP over ADP as a substrate, are found in most nephron segments beyond the proximal tubule. NPPs catalyse not only the hydrolysis of ATP and ADP, but also of diadenosine polyphosphates. NPP1 has been identified in proximal and distal tubules of the mouse, while NPP3 is expressed in the rat glomerulus and pars recta, but not in more distal segments. Ecto-5′-nucleotidase, which catalyses the conversion of AMP to adenosine, is found in apical membranes of rat proximal convoluted tubule and intercalated cells of the distal nephron, as well as in the peritubular space. Finally, an alkaline phosphatase, which can theoretically catalyse the entire hydrolysis chain from nucleoside triphosphate to nucleoside, has been identified in apical membranes of rat proximal tubules; however, this enzyme exhibits relatively high K m values for adenine nucleotides. Although information on renal ectonucleotidases is still incomplete, the enzymes' varied distribution in the vasculature and along the nephron suggests that they can profoundly influence purinoceptor activity through the hydrolysis, and generation, of agonists of the various purinoceptor subtypes. This review provides an update on renal ectonucleotidases and speculates on the functional significance of these enzymes in terms of glomerular and tubular physiology and pathophysiology.

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Effect of atrial natriuretic factor and cyclic guanosine monophosphate on water and urea transport in the inner medullary collecting duct

Rocha

Kudo

1990

Pflugers Arch.

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We examined the action of high (2 x 10(-8)M) and low (6 x 10(-9)M) concentrations of atrial natriuretic factor (ANF) on water and urea transport in the rat inner medullary collecting duct (IMCD) using the in vitro microperfusion technique. We measured the hydraulic conductivity (Lp x 10(-6) cm/atm per second) and both lumen-to-bath (Pu(lb] and bath-to-lumen (Pu(bl)) 14C-urea permeabilities (Pu x 10(-5) cm/s) in the absence and in the presence of vasopressin (VP). High concentrations of ANF were able to inhibit the maximum activity of (50 microU/ml) VP-stimulated Lp but physiological concentration of ANF inhibit only submaximum activity (10 microU/ml) of VP-stimulated Lp. The hydrosomotic effect of dibutyryl-cyclic 3.5 adenosine monophosphate (cAMP) (10(-4)M) was unchanged by high concentrations of ANF (2 x 10(-8)M). Also we found that high (10(-4)M) and low (10(-6)M) concentrations of exogenous cyclic 3,5-guanosine monophosphate (GMP) while unable to change the Lp in the absence of VP, decreased the maximum activity of VP-stimulated Lp significantly. We also found that ANF inhibits partially and in a reversible manner the VP-stimulated Pu(lg) but not the VP-stimulated Pu(bl). These results demonstrated that plasma concentrations of ANF observed during volume expansion (10(-10)M) are able to inhibit submaximum activity of VP-stimulated (10 microU/ml) Lp in the rat IMCD, this effect seems to occur before cAMP formation and it appears to be mediated by cGMP. ANF (6 x 10(-9)M) also reduced the VP-stimulated urea outflux.(ABSTRACT TRUNCATED AT 250 WORDS)

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Distribution of enzymes of adenylate and guanylate nucleotide metabolism in rat nephron

Cited by 6 publications

References 0 publications

Localization of Low-K<sub>M</sub> cAMP Phosphodiesterase in Rat Nephron Segments

Localization of Low-K<sub>M</sub> cAMP Phosphodiesterase in Rat Nephron Segments

Ectonucleotidases in the kidney

Effect of atrial natriuretic factor and cyclic guanosine monophosphate on water and urea transport in the inner medullary collecting duct

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