QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wu, G. Articles by Morris, S. M. Search for Related Content PubMed PubMed Citation Articles by Wu, G. Articles by Morris, S. M., Jr.

---

Article

A Cortisol Surge Mediates the Enhanced Expression of Pig Intestinal Pyrroline-5-Carboxylate Synthase during Weaning¹

Guoyao Wu^*,2, Cynthia J. Meininger, Katherine Kelly, Malcolm Watford ^** and Sidney M. Morris, Jr.

^* Faculty of Nutrition and Department of Animal Science, Texas A&M University, College Station, TX 77843; Department of Medical Physiology, Texas A&M University System Health Science Center, College Station, TX 77843; ^** Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ 08901; and Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261

²To whom correspondence should be addressed.

Citrulline synthesis from glutamine is enhanced remarkably in enterocytes of weanling pigs, but the molecular mechanism(s) involved are not known. The objective of this study was to determine whether a cortisol surge mediates the enhanced expression of intestinal citrulline-synthetic enzymes during weaning. Jejunal enterocytes were prepared from 29-d-old weanling pigs treated with or without metyrapone (an inhibitor of cortisol synthesis), or from age-matched unweaned pigs. The mRNA levels and activities of phosphate-dependent glutaminase (PDG), pyrroline-5-carboxylate synthase (P5CS), ornithine aminotransferase (OAT), carbamoyl-phosphate synthase I (CPS-I) and ornithine carbamoyltransferase (OCT) were determined. The mRNA levels for PDG, P5CS, OAT and OCT were 139, 157, 102 and 55% higher, respectively, in weanling pigs compared with suckling pigs. The activities of PDG and P5CS were 38 and 692% higher, respectively, in weanling pigs compared with unweaned pigs, but the activities of OAT, CPS-I and OCT did not differ between these two groups of pigs. The effects of metyrapone administration to weanling pigs were as follows: 1) prevention of a cortisol surge, 2) abolition of the increases in both mRNA levels and activity of P5CS, 3) no alteration in the mRNA levels and activities of PDG and CPS-I, 4) increases in the mRNA levels for OAT (216%) and OCT (39%) and in OAT activity (30%), and 5) prevention of the increase in intestinal synthesis of citrulline from glutamine. These results suggest that increased P5CS activity reflects in large part the increased levels of P5CS mRNA and is responsible for the increased synthesis of citrulline from glutamine in enterocytes of weanling pigs; these increases may be mediated by a cortisol surge during weaning that can be blocked by metyrapone administration.

KEY WORDS: • citrulline • enterocytes • metyrapone • cortisol • weaning • pigs

This article has been cited by other articles:

				M. A. M. Spreeuwenberg, J. M. A. J. Verdonk, H. R. Gaskins, and M. W. A. Verstegen Small Intestine Epithelial Barrier Function Is Compromised in Pigs with Low Feed Intake at Weaning J. Nutr., May 1, 2001; 131(5): 1520 - 1527. [Abstract] [Full Text]