ISSN:
1432-2013
Keywords:
l-Glucose
;
Micropuncture and Microperfusion
;
Proximal Tubule
;
Active Secretion
;
Kinetic Study
;
l-Glucose
;
Mikropunktion und Mikroperfusion
;
proximaler Tubulus
;
aktive Sekretion
;
kinetische Studien
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Studies with the free flow micropuncture technique have shown that the ratio of TF/Pl-glucose to TF/PInulin in proximal tubular fluid, in distal tubular fluid, and in more than half of the final urine samples measured was greater than one, which suggests thatl-glucose was actively secreted. Studies with the microperfusion technique confirmed this finding and showed thatl-glucose was secreted by the proximal tubules. A maximum rate of secretion was reached at a plasma concentration of 4 mM. The tubular secretion ofl-glucose was augmented by the presence of 16.6 mMd-glucose in tubular lumen and inhibited by 10−4 M phlorizin. Kinetic analysis showed that theV max values forl-glucose secretion in the absence and in the presence ofd-glucose are 5.0×10−10 and 6.3×10−10 mol×cm−2×sec−1 respectively which were very close to the value reported for theV max ford-glucose reabsorption. However, theK m forl-glucose secretion was 3.1 mM and was reduced to 1.6 mM whend-glucose was present in the perfusion fluid. TheK m ford-glucose reabsorption has been reported to be 0.6 mM (8). The results of this investigation were interpreted as being consistant with the hypothesis thatl-glucose secretion andd-glucose reabsorption share the same carrier system.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00585842
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