AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 2 334-R342, Copyright © 1995 by American Physiological Society
Glutamine and glucose metabolism in enterocytes of the neonatal pig
G. Wu, D. A. Knabe, W. Yan and N. E. Flynn
Department of Animal Science, Texas A&M University, College Station 77843.
Glutamine and glucose metabolism was studied in 0- to 21-day-old pig
enterocytes. Cells were incubated at 37 degrees C for 30 min in
Krebs-Henseleit bicarbonate buffer (pH 7.4) in the presence of 2 mM
[U-14C]glutamine with or without 5 mM glucose, or 5 mM [U-14C]glucose with
or without 2 mM glutamine. Glutamine was metabolized to ammonia, glutamate,
alanine, aspartate, CO2, citrulline, ornithine, and proline, whereas
glucose was converted to lactate, pyruvate, and CO2 in pig enterocytes. CO2
production from glutamine accounted for 32-36% and 3-4% of utilized
glutamine carbons in 0- to 7-day-old and 14- to 21-day-old pigs,
respectively. The rates of O2 consumption and metabolism of glutamine and
glucose decreased in enterocytes from 2- to 14-day-old pigs compared with
0-day-old pigs. By day 14 after birth, the oxidation of glutamine and
glucose as well as citrulline production had decreased by 90-95%. Arginine
synthesis from glutamine occurred in cells from 0- to 7-day-old pigs but
not 14- to 21-day-old ones. Glucose (5 mM) had no effect on glutamine
utilization and oxidation or the production of glutamate and arginine but
stimulated the formation of alanine, citrulline, and proline at the expense
of aspartate. In contrast, glutamine (2 mM) inhibited glycolysis and
glucose oxidation in cells from 0- to 7-day-old pigs and had no effects in
14- to 21-day-old pigs. As a result, glutamine contributed approximately
2-fold greater amounts of ATP to 0- to 7-day-old pig enterocytes than
glucose.(ABSTRACT TRUNCATED AT 250 WORDS)
