A Micropuncture Study of the Response of Superficial and Juxtamedullary Nephrons to an Acute Sodium Load1

2015 ◽  
pp. 271-283
Author(s):  
R. L. Jamison
Keyword(s):  
Micropuncture Study

Micropuncture Study of Glomerulotubular Balance in the Rat Kidney

Nephron ◽  
1969 ◽  
Vol 6 (3) ◽  
pp. 418-436 ◽  
Author(s):  
Elvira E. Arrizurieta-Muchnik ◽  
W.E. Lassiter ◽  
Eleanor M. Lipham ◽  
C.W. Gottschalk
Keyword(s):  
Rat Kidney ◽  
Micropuncture Study ◽  
Glomerulotubular Balance

Electrolyte handling by the superficial nephron of the rabbit

1986 ◽  
Vol 250 (4) ◽  
pp. F590-F595 ◽  
Author(s):  
N. L. Wong ◽  
S. J. Whiting ◽  
C. L. Mizgala ◽  
G. A. Quamme
Keyword(s):  
Glomerular Filtration Rate ◽  
Proximal Tubule ◽  
Concentration Ratio ◽  
Filtration Rate ◽  
Distal Tubule ◽  
Mean Value ◽  
Loop Of Henle ◽  
Collection Site ◽  
Micropuncture Study ◽  
The Mean

A micropuncture study of the rabbit was performed to evaluate the function of the superficial nephron. The mean glomerular filtration rate of the left micropunctured kidney was 4.0 +/- 0.8 ml/min. The concentration profile of electrolytes within the proximal tubule was similar to that of species previously investigated except for potassium. The mean tubular fluid (TF)-ultrafilterable (UF) concentration ratios were as follows: sodium, 1.01 +/- 0.03; chloride, 1.14 +/- 0.04; calcium, 1.12 +/- 0.04; magnesium, 1.47 +/- 0.08; and phosphate, 0.94 +/- 0.09, with a mean TF-plasma (P) inulin concentration ratio of 1.78 +/- 0.14 (n = 32). The TF/UF potassium value significantly increased in association with TF/P inulin to a mean value of 1.26 +/- 0.06. Accordingly, 29% of the filtered potassium was reabsorbed in the superficial proximal tubule compared with 43% of the filtered sodium. The loop of Henle reabsorbed 55-60% of the filtered sodium, chloride, and calcium, whereas considerably less magnesium (33%) was reabsorbed. Segments beyond the distal tubule collection site reabsorbed little of the delivered magnesium, which supports the notion that the loop of Henle is the principal segment accounting for adjustments in magnesium balance. These studies indicate that the superficial nephron of the rabbit performs similar to other species reported, except potassium reabsorption is significantly less in the proximal convoluted tubule.

Micropuncture study of composition of proximal and distal tubular fluid in rat kidney

1963 ◽  
Vol 204 (4) ◽  
pp. 527-531 ◽  
Author(s):  
Karl J. Ullrich ◽  
Bodil Schmidt-Nielsen ◽  
Roberta O'Dell ◽  
Gundula Pehling ◽  
Carl W. Gottschalk ◽  
...  
Keyword(s):  
Sodium Transport ◽  
Rat Kidney ◽  
Active Sodium ◽  
Osmotic Diuresis ◽  
Active Sodium Transport ◽  
Anesthetized Rats ◽  
Micropuncture Study

Fluid was collected by micropuncture from proximal and distal convolutions of anesthetized rats and analyzed for inulin, sodium, urea, and total osmotically active solute. The proximal fluid/plasma (F/P) sodium ratio was not significantly different from unity in antidiuretic animals, but was as low as 0.78 during mannitol diuresis. The distal F/P sodium ratio averaged 0.62 in antidiuresis, and 0.24 during osmotic diuresis. The data are interpreted to indicate active sodium transport by both proximal and distal convolutions. The F/P ratios for inulin, urea, and total osmotically active solute are in general agreement with previous studies.

Micropuncture study of ammonia excretion in the rat

1963 ◽  
Vol 205 (1) ◽  
pp. 127-132 ◽  
Author(s):  
Sheldon Glabman ◽  
R. M. Klose ◽  
Gerhard Giebisch
Keyword(s):  
Proximal Tubule ◽  
Ammonium Chloride ◽  
Ammonia Excretion ◽  
The Other ◽  
Water Reabsorption ◽  
Micropuncture Study

Ammonia has been determined in blood and in samples of tubular fluid obtained by micropuncture at various sites along the nephron from two groups of rats, one untreated and the other pretreated with ammonium chloride. Ammonia has been found in tubular fluid from all segments of the nephron, the concentrations being generally higher in those animals which were pretreated with ammonium chloride. In addition, there is a tendency for the concentration of ammonia to increase as the site of micropuncture progresses along the nephron. In the proximal tubule, concentrations of ammonia have been found which are greater than can be accounted for solely by the extraction of water in this segment. This is taken to indicate tubular addition of ammonia at this site. Since the increments of ammonia along the nephron generally exceed that which could be due to water reabsorption, it is concluded that all parts of the nephron contribute to urinary ammonia excretion.

A Micropuncture Study of Kidney Function in the River Lamprey Lampetra Fluviatilis Adapted to Sea Water

1980 ◽  
Vol 88 (1) ◽  
pp. 239-248
Author(s):  
A. G. LOGAN ◽  
R. MORRIS ◽  
J. C. RANKIN
Keyword(s):  
Fresh Water ◽  
Kidney Function ◽  
Sea Water ◽  
Chloride Ions ◽  
Water Reabsorption ◽  
Plasma Electrolyte ◽  
River Lamprey ◽  
Micropuncture Study ◽  
Urine Composition ◽  
High Concentrations

Micropuncture techniques have been used to investigate kidney function in lampreys adapted to hyperosmotic media. Plasma electrolyte concentrations were maintained well below corresponding concentrations in the external environment. Urine composition was variable, but generally showed high concentrations of magnesium, sulphate and chloride ions. Lampreys in 50% sea water produced urine which was hypo or iso-osmotic to plasma, whereas those in 100% sea water produced hyperosmotic urine. Urine flow rate in 50% sea water was one tenth of that in fresh water, due to a reduction in filtration rate and an increase in water reabsorption by the kidney. As in fresh water, little if any filtered water was reabsorbed by the proximal segment. Almost 90% of filtered water was reabsorbed by the kidney of 100% sea water lampreys and most of this must have occurred in the distal and collecting segments.

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