Evaluation of Single Nephron Filtration Rate (SNGFR) Using Two Different Micropuncture Techniques1

2015 ◽  
pp. 33-42
Author(s):  
K. Hierholzer ◽  
M. Butz
Keyword(s):  
Filtration Rate ◽  
Nephron Filtration Rate ◽  
Single Nephron Filtration Rate ◽  
Single Nephron

Measurement of Single Nephron Filtration Rate in the Kidney of the River Lamprey, Lampetra Fluviatilis L

1978 ◽  
Vol 77 (1) ◽  
pp. 57-69 ◽  
Author(s):  
R. J. MORIARTY ◽  
A. G. LOGAN ◽  
J. C. RANKIN
Keyword(s):  
Filtration Rate ◽  
Gel Filtration ◽  
Reference Substance ◽  
Nephron Filtration Rate ◽  
River Lamprey ◽  
Peritubular Capillaries ◽  
Single Nephron Filtration Rate ◽  
Single Nephron ◽  
51Cr Edta ◽  
Renal Clearances

The reliability of [3H]inulin as a reference substance for the measurement of glomerular filtration rate (GFR) in river lampreys was investigated. Simultaneously measured renal clearances of [3H]inulin and [14C]-polyethylene glycol (PEG) were not significantly different. Recoveries of [3H]inulin in the urine following its injection into the proximal tubule and urinary duct averaged 83.5±4.0% (n = 14) and 93.0±4.6% (n = 9) respectively. No evidence was obtained to suggest penetration of the tubular wall by [3H]inulin following its introduction into peritubular capillaries. Gel-filtration of lamprey plasma and urine produced no signs of any significant degradation of the inulin to fructose. [3H]inulin recoveries, though significantly below 100% (P < 0.001), were considered adequate to justify its use after allowing for possible sources of error. A mean single nephron filtration rate (SNGFR) value of 7.02±0.27 nl/min (n = 89) was obtained from the kidneys of anaesthetized freshwater lampreys. [51Cr]EDTA was found to be totally unsuitable for the measurement of GFR in this species.

Measurement of nephron filtration in the dog: role of proximal intratubular pressure

1981 ◽  
Vol 241 (3) ◽  
pp. F238-F243
Author(s):  
D. A. Hartupee ◽  
A. H. Gillies ◽  
F. G. Knox
Keyword(s):  
Proximal Tubule ◽  
Filtration Rate ◽  
Free Flow ◽  
Nephron Filtration Rate ◽  
Intratubular Pressure ◽  
Single Nephron Filtration Rate ◽  
Single Nephron ◽  
Proximal Tubular ◽  
Pressure Controlled

Previous studies concerning the measurement of single nephron filtration rate have shown that collections of proximal tubular fluid, in which an oil drop is held in a constant position, do not affect intratubular pressure in the early proximal tubule in the hydropenic rat. Since intratubular pressures are higher in the dog than the rat, we investigated the effect of position-controlled collections on proximal pressure and single nephron filtration rate (SNGFR) in the dog. During position-controlled collections, early proximal pressure fell 5.8 +/- 0.9 mmHg and SNGFR was 76.3 +/- 5.3 nl/min. During proximal re-collections, in which proximal pressure was maintained near the free-flow value using a long immobile oil block, SNGFR was significantly less, 44.4 +/- 5.5 nl/min. For each micropunctured kidney, SNGFR was also estimated by dividing GFR by the number of glomeruli (mean, 5.4 +/- 0.5 X 10(5)). Estimated SNGFR (50.9 +/- 6.3 nl/min) was not significantly different from pressure-controlled SNGFR but was significantly less than position-controlled SNGFR. Accordingly, in the dog, early proximal pressure decreases during position-controlled collection of proximal tubular fluid, resulting in an overestimation of SNGFR. This artifact can be avoided by controlling the intratubular pressure during collection of tubular fluid.

scholarly journals Autoregulation of Single Nephron Filtration Rate in the Presence and the Absence of Flow to the Macula Densa

1974 ◽  
Vol 34 (6) ◽  
pp. 836-840 ◽  
Author(s):  
FRANKLYN G. KNOX ◽  
COBERN OTT ◽  
JEAN-LOUIS CUCHE ◽  
JOSIANNE GASSER ◽  
JOHN HAAS
Keyword(s):  
Filtration Rate ◽  
Macula Densa ◽  
Nephron Filtration Rate ◽  
Single Nephron Filtration Rate ◽  
Single Nephron

Single-nephron filtration rate in the dog

1972 ◽  
Vol 222 (3) ◽  
pp. 667-673 ◽  
Author(s):  
EG Schneider ◽  
RE Lynch ◽  
LR Willis ◽  
FG Knox
Keyword(s):  
Filtration Rate ◽  
Nephron Filtration Rate ◽  
Single Nephron Filtration Rate ◽  
Single Nephron

Proximal tubular function in transgenic mice overexpressing atrial natriuretic factor

1994 ◽  
Vol 72 (10) ◽  
pp. 1168-1170 ◽  
Author(s):  
H. Sonnenberg ◽  
U. Honrath ◽  
C. K. Chong ◽  
L. J. Field ◽  
A. T. Veress
Keyword(s):  
Atrial Natriuretic Factor ◽  
Filtration Rate ◽  
Tubular Function ◽  
Nephron Filtration Rate ◽  
Natriuretic Factor ◽  
Single Nephron Filtration Rate ◽  
Single Nephron ◽  
Proximal Tubular ◽  
Proximal Tubular Function ◽  
Atrial Natriuretic

A transgenic mouse model in which atrial natriuretic factor (ANF) expression is targeted to the liver was used to study intrarenal adjustments to the chronically elevated hormone level. Such animals, designated TTR-ANF, are characterized by reduced arterial blood pressure but similar sodium excretion compared with nontransgenic siblings. Proximal tubular micro-puncture gave the following results: single-nephron filtration rate = 12.7 ± 1.1 vs. 15.6 ± 1.9 nL/min (TTR-ANF versus nontransgenic, ns); end-proximal tubular fluid/plasma concentration ratio of inulin = 1.93 ± 0.09 vs. 1.97 ± 0.15 (ns); fractional reabsorption of sodium = 45.5 ± 2.8 vs. 46.0 ± 3.8% (ns); fractional reabsorption of chloride = 33.6 ± 3.3 vs. 32.4 ± 4.1% (ns). These data indicate that life-long elevation of plasma ANF concentration was not associated with significant alteration in single-nephron filtration rate and proximal tubular function. We conclude that compensatory anti-natriuretic mechanisms, localized downstream from the proximal tubule, can prevent ANF natriuresis.Key words: micropuncture, single-nephron filtration rate, sodium chloride reabsorption.

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