A Micropuncture Study of Glomerular Filtration and Tubular Reabsorption of Endogenous Renin in the Rat

Leyssac, P. P.

doi:10.1159/000172660

Cited by 13 publications

(11 citation statements)

References 10 publications

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“…Micropuncture studies of rat PTs have provided direct evidence that this small protein (36 to 40 kDa) can be found in glomerular ultrafiltrate at a fifth of its plasma concentration and that it is rapidly reabsorbed along the PT. 7 The escape of even a small fraction from such fate could contribute substantially to renin in final urine, however. Although renin may also be synthesized in PTs, 8 this contribution is likely to be small at best, as it is not detected by immunohistochemistry of renal tissue.…”

Section: Lantelme Et Al Urinary Angiotensinogen and Dietary Sodium 1011mentioning

confidence: 99%

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Effects of Dietary Sodium and Genetic Background on Angiotensinogen and Renin in Mouse

et al. 2002

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Abstract-Elements of a renin-angiotensin system expressed along the entire nephron, including angiotensinogen secreted by proximal tubule and renin expressed in connecting tubule, may participate in the regulation of sodium reabsorption at multiple sites of the nephron. The response of this tubular renin-angiotensin system to stepwise changes in dietary sodium was investigated in 2 mouse strains, the sodium-sensitive inbred C57BL/6 and the sodium-resistant CD1 outbred. Plasma angiotensinogen was not affected by sodium regimen, whereas plasma renin increased 2-fold under low sodium. In both strains, the variation in urinary parameters did not parallel the changes observed in plasma. Angiotensinogen and renin excretion were significantly higher under high sodium than under low sodium. Water deprivation, by contrast, induced significant activation in the tubular expression of angiotensinogen and renin. C57BL/6 exhibited significantly higher urinary excretion of angiotensinogen than did CD1 animals under both conditions of sodium intake. The extent to which these urinary parameters reflect systemic or tubular responses to challenges of sodium homeostasis may depend on the relative contribution of sodium restriction and volume depletion. Key Words: angiotensinogen Ⅲ renin Ⅲ sodium Ⅲ mouse Ⅲ genetics Ⅲ urine W e have advanced the hypothesis that a paracrine tubular renin-angiotensin system operates along the entire nephron. 1 Although angiotensinogen (AGT) is not filtered across the glomerular membrane, the protein 2 and its mRNA 3,4 have been detected in proximal tubule (PT), the protein is secreted to the apical side of PT cell monolayers, 1 has been detected in final urine under normal physiological conditions, 5 and was detected in luminal fluid of PT epithelium collected by micropuncture. 6 Systemic renin is filtered and reabsorbed in the PT. 7 Although not detected in situ, it may be expressed at low level in the PT. 8,9 We have found that renin was also synthesized and secreted in connecting tubule (CNT). 1 ACE and angiotensin (Ang) II receptors are expressed along the nephron. 10,11 High luminal Ang II has been observed in the PT, 12,13 where it stimulates sodium reabsorption. 14 Some observations support a similar role in terminal segments of the nephron. 15 The potential significance of this tubular renin-angiotensin system in blood pressure regulation is underlined by the observation that double transgenic animals overexpressing human renin systemically and human AGT in the PT develop hypertension. 16 The impact of dietary sodium on the expression of renin and tubular AGT and the significance of their urinary excretion as indicators of the activity of this tissue system were tested in the mouse. Two strains were investigated, C57BL/6 and CD1. The C57BL/6 inbred differs from other inbred lines in its response to dietary sodium 17 ; its sodium sensitivity has been demonstrated 18,19 and exploited in an attempt to map genetic determinants of the arterial pressure response to dietary sodium. 19 We have verified...

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Section: Lantelme Et Al Urinary Angiotensinogen and Dietary Sodium 1011mentioning

confidence: 99%

“…6 Systemic renin is filtered and reabsorbed in the PT. 7 Although not detected in situ, it may be expressed at low level in the PT. 8,9 We have found that renin was also synthesized and secreted in connecting tubule (CNT).…”

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confidence: 95%

Effects of Dietary Sodium and Genetic Background on Angiotensinogen and Renin in Mouse

et al. 2002

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“…A micropuncture study confirmed that renin concentration in the ultrafiltrate in Bowman's capsule was about 20% of the arterial plasma concentration. 8 Using autoradiographic techniques, we 9 found that intravenously injected IZ5 I-labeled renin accumulated mainly in the renal cortex in mice, particularly in the proximal tubules. Bailie et al, 6 in stop-flow studies in dogs, suggested that filtered renin was reabsorbed in the proximal nephron segment.…”

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Urinary excretion of renin and its biochemical properties in dogs.

Yukimura¹,

Miura²,

Matsushima³

et al. 1984

Hypertension

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TOKIHITO YUKIMURA, KATSUYUKI MIURA, YOHKAZU MATSUSHIMA, FUMIHIKO IKEMOTO, AND KENJIRO YAMAMOTO SUMMARY The amount and biochemical properties of renin excreted by anesthetized dogs were investigated to elucidate the significance of urinary excretion in the metabolism of renin. Mean arterial blood pressure was 127 ± 4 mm Hg, renal blood flow was 170 ± 8 ml/min, glomerular filtration rate, 38.6 ± 2.3 ml/min, and urine flow rate, 0.37 ± 0.09 ml/min (n = 11). Urinary renin concentration (URC) was 9.2 ± 2.1 ng angiotensin I (ANG I)/ml-hr (n = 11), as determined by radioimmunoassay for ANG I generated by incubation with semipurified homologous renin substrate. The ANG I-producing activity was inhibited by more than 90% by a specific antibody to dog kidney renin. The renin secretion rate from the left kidney into the renal vein was 76.4 ± 13.3 ng ANG 1/ ml-hr per min (n = 11), and the simultaneous urinary excretion rate of renin was 2.3 ± 0.4 ng ANG 1/ ml-hr per min(n = 11). Molecular weight of the urinary renin was 40,000 daltons. The pH dependent curves of the angiotensin-forming capacity of renin showed an optimum between pH 5.5 to 6.0, and the estimated Michaelis constant was 0.42 /J,M. These biochemical parameters were similar to the findings in the case of renin in the plasma and the kidney. Moreover, neither acid nor trypsin treatment altered the renin activity in the urine. Thus, the active form of renin with a molecular weight 40,000 was excreted into the urine in dogs. Urinary excretion of renin was a small percentage of the renin secretion rate, thereby indicating the minor role of urinary excretion in the metabolism of renin. (Hypertension 6: 837-842, 1984) KEY WORDS • antirenin antibody • renin secretion rate high performance liquid chromatography

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“…Recent evidence sug gests that renin may be filtered in the mouse kidney and subsequently pinocytozed in the proximal tubule [28], In addition, Leyssac [16] has suggested that glomerular filtration in the rat removes 5.4% of the renin carried to the afferent arteriole and 16.4% of the net RSR. Accordingly, we attempted to deter mine if the reduction in RSR and the nega tive (V-A) PRA differences observed in our initial experiments correlated with a loss of renin into the urine.…”

Section: Discussionmentioning

confidence: 99%

Contralateral Renal Function Following Unilateral Renal Artery Constriction

Murray¹,

Hackenthal²,

Mittmann³

et al. 1982

Kidney Blood Press Res

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The acute (0.5–3.0 h) response of the contralateral kidney to unilateral renal artery constriction was studied in 7 pentobarbital-anesthetized dogs. Within 30 min after unilateral renal artery constriction to a pressure of about 60 mm Hg, contralateral vascular resistance, sodium excretion and filtration fraction increased significantly while glomerular filtration rate, blood flow and plasma flow did not change. Renin secretion decreased dramatically within 30 min, demonstrating a negative venous minus arterial plasma renin activity in some dogs. Unilateral renal artery constriction did not change the rate of angiotensin II extraction across the contralateral kidney or the urinary renin activity (measured in 4 dogs). These results indicate that the acute response of the contralateral kidney to unilateral renal artery constriction is somewhat different from that seen in the chronic state.

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A Micropuncture Study of Glomerular Filtration and Tubular Reabsorption of Endogenous Renin in the Rat

Cited by 13 publications

References 10 publications

Effects of Dietary Sodium and Genetic Background on Angiotensinogen and Renin in Mouse

Effects of Dietary Sodium and Genetic Background on Angiotensinogen and Renin in Mouse

Urinary excretion of renin and its biochemical properties in dogs.

Contralateral Renal Function Following Unilateral Renal Artery Constriction

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