Human kidney free fatty acid and glucose uptake: evidence for a
renal glucose-fatty acid cycle.
Meyer, C., V. Nadkarni, M. Stumvoll, and J. Gerich.
Departments of Medicine, Physiology and Pharmacology, University of
Rochester, School of Medicine, Rochester, New York 14642 USA
APStracts 4:0128E, 1997.
To determine the relationship between FFA and glucose uptake by the
human kidney, 12 postabsorptive normal volunteers underwent renal
vein catheterization and were infused to isotopic steady state with
[6-3H] glucose and [9,10-3H] palmitate. Arterial and renal vein
palmitate specific activities were not significantly different
(3533+/-219 vs 3549+/-220 dpm/_mol, p=0.64). Palmitate renal
fractional extraction and uptake determined isotopically (7.2+/-1.1%
and 9.1+/-1.4 _mol/min) were not significantly different from those
calculated by net balance measurements (8.3+/-1.2% and 9.7+/-1.2
_mol/min, p>0.07 and >0.7 respectively). Renal palmitate uptake
accounted for 8.7+/-1.3% of its systemic turnover. Renal linoleate
and oleate fractional extraction calculated by net balance
measurements (8.0+/-0.9 and 7.7+/-1.2%, respectively) were not
significantly different from each other and that of palmitate (all,
p>0.7). Renal uptake of palmitate, linoleate (7.9+/-1.0 _mol/min)
and oleate (10.9+/-2.0 _mol/min) were all directly proportional to
their arterial concentrations (r= 0.70, 0.68 and 0.63 respectively,
all p<0.025). Renal glucose uptake (93+/-10 _mol/min) accounted for
12.6 +/- 1.5% of its systemic turnover and was inversely related to
the sum of palmitate, linoleate and oleate uptake (r = -0.74,
p<0.01). These data indicate that in postabsorptive humans: 1) the
kidney is an important site of FFA and glucose disposal, 2) a renal
glucose fatty acid cycle may exist and 3) there appears to be little
or no release into the circulation of stored renal FFA.
Received 14 February 1997; accepted in final form 5 June 1997.
APS Manuscript Number E72-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 1 July 1997