Enhanced metabolism of arginine and glutamine in enterocytes of
cortisol-treated pigs.
Flynn, Nick E., and Guoyao Wu.
Faculty of Nutrition and Departments of Animal Science and Medical
Physiology, Texas A&M University, College Station, Texas 77843
-2471, Tel. 409-845-1817, Fax 409-845-5292
APStracts 3:0198G, 1996.
This study was designed to determine whether cortisol plays a role in
arginine and glutamine metabolism in enterocytes and more
specifically whether cortisol regulates metabolic changes in these
cells during weaning. Twenty eight 21-day-old suckling pigs were
randomly assigned to one of four groups with seven animals each, and
received intramuscular injections of vehicle solution (sesame oil)
(control group), hydrocortisone-21-acetate (HYD) (25 mg/kg body wt),
RU486 (10 mg/kg body wt) (a potent blocker of glucocorticoid
receptors), or HYD plus RU486. At 29 days of age, pigs were
sacrificed for preparation of jejunal enterocytes. During the entire
experimental period, pigs were nursed by sows. Activities of
argininosuccinate synthase (ASS), argininosuccinate lyase (ASL),
arginase and pyrroline-5-carboxylate (P5C) synthase were measured.
For metabolic studies, enterocytes were incubated for 30 min at 37
degrees C in 2 ml of Krebs-bicarbonate buffer (pH 7.4) containing 0,
0.5 or 2 mM [U-14C]arginine or [U-14C]glutamine. Cortisol
administration increased i) the activities of ASL and arginase and
the production of CO2, ornithine and proline from arginine, and ii)
P5C synthase activity and the formation of glutamate, alanine,
aspartate, ornithine, citrulline, proline and CO2 from glutamine in
enterocytes, compared with the control group. The stimulating effects
of cortisol on the enzyme activities and the metabolism of arginine
and glutamine were abolished by co-administration of RU486. Our data
suggest that cortisol plays an important role in regulating arginine
and glutamine metabolism in enterocytes via a glucocorticoid
receptor-mediated mechanism.
Received 26 June 1996; accepted in final form 6 September 1996.
APS Manuscript Number G254-6.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 7 October 1996