ISSN:
1432-2013
Keywords:
Glomerular filtration
;
Nephron
;
Ferrocyanide
;
SNGFR
;
Environmental salinity
;
Teleost fish
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract 1. Trout kidney slices incubated in the presence of14C-sodium ferrocyanide accumulated radioactivity. Uptake by individual nephroi increased with time, stabilizing after 30 min. The greater the concentration of radioactivity the greater the uptake per mm of tubule, while reduced specific activity inhibited14C uptake. 2. The renal excretory pattern of14C-sodium ferrocyanide was compared with that of3H-inulin in fresh water adapted trout. The renal clearance rates of the substances were similar and linearly related over a range or urine flows, providing plasma ferrocyanide concentrations were between 1.5 and 2.5 mM.14C-ferrocyanide is thus a reliable marker for glomerular activity in this species. 3. A protocol for the determination of single nephron glomerular filtration rates (SNGFR) in trout is described. The method exploits the ability to visualize ferrocyanide as Prussian Blue within nephroi after a single pulse injection superimposed upon a constant infusion of14C-ferrocyanide. The effects of surgical procedure and extraluminal contamination are assessed. 4. The SNGFR of freshwater trout, 1.31±0.2 nl/min is approximately 65% less than that observed in sea water adapted fish (3.74±1.12 nl/min). The overall, total kidney glomerular filtration rate, (GFR) is 142.6±17.4 μl/min/kg in fresh water animals and 20.1±0.9 μl/min/kg in sea water fish. 5. It is concluded that whilst SNGFRs of sea water animals are higher than those of fresh water animals, filtration is distributed to nephron populations selected to meet the homeostatic demands of the organism.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00584381
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