Early Weaning Induces Jejunal Ornithine Decarboxylase and Cell Proliferation in Neonatal Rats

Manuscript received 28 October 1997. Initial reviews completed 5 January 1998. Revision accepted 1 July 1998.

Chuan-Hao Lin, Leena Correia, Ketan Tolia, Mark S. Gesell^*, Vasundhara Tolia, Ping-Cheung Lee, and Gordon D. Luk^*

Departments of Pediatrics, Wayne State University and Childrens Hospital of Michigan, Detroit, MI 48201; ^* Department of Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75235;  Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226

Increased ornithine decarboxylase (ODC) activity is associated with rapid cell proliferation in many cell types. The cellular effects of early weaning on intestinal development are not well established. To investigate whether ODC is involved in intestinal growth after early weaning, we precociously weaned suckling rats on postnatal d 15 and followed through d 21 (6 d after early weaning). Age-matched suckling pups served as controls. Rat pups were killed 1, 2, 3 and 6 d after early weaning and jejunal mucosa was assayed for ODC and sucrase activities, and protein and DNA contents. Jejunal cell proliferation was monitored by bromodeoxyuridine immunohistochemistry. Elevated jejunal ODC activity 1 d after early weaning was the earliest cellular event that was detected in the current study. ODC activity peaked at d 3 (about 15-fold greater than age-matched unweaned suckling controls). Sucrase activity was elevated at d 2 after weaning and peaked at d 3 (about 10-fold greater than controls). Greater bromodeoxyuridine immunostaining in early weaned rats occurred on d 3. Protein and DNA contents were greater in jejunal mucosa of early weaned rats at d 6. Serum corticosterone levels were elevated on d 1 and d 2 after early weaning compared to controls. To explore whether the intake of nonpurified diet played a role, we also compared the induction of jejunal ODC activity in early weaned pups and pups that were food-deprived for 1 d. ODC activity was not greater in the food-deprived group compared to suckling controls while the early weaned group had 6-fold greater activity 1 d after early weaning. Early weaning stimulates jejunal cell proliferation and differentiation. The temporal sequence of increased ODC activity followed by increases in other growth variables suggests that the induction of ODC activity may act as an early marker of intestinal growth during early weaning.

The Journal of Nutrition Vol. 128 No. 10 October 1998, pp. 1636-1642
Copyright ©1998 by the American Society for Nutritional Sciences

This article has been cited by other articles:

				C. S. Park Role of compensatory mammary growth in epigenetic control of gene expression FASEB J, October 1, 2005; 19(12): 1586 - 1591. [Abstract] [Full Text] [PDF]

				S. T. Hwang and S. J. Henning Ontogenic Regulation of Components of Ileal Bile AcidAbsorption Experimental Biology and Medicine, July 1, 2001; 226(7): 674 - 680. [Abstract] [Full Text] [PDF]

				P. Gama and E. P. Alvares Early Weaning and Prolonged Nursing Induce Changes in Cell Proliferation in the Gastric Epithelium of Developing Rats J. Nutr., October 1, 2000; 130(10): 2594 - 2598. [Abstract] [Full Text]

				G. Wu, N. E. Flynn, and D. A. Knabe Enhanced intestinal synthesis of polyamines from proline in cortisol-treated piglets Am J Physiol Endocrinol Metab, August 1, 2000; 279(2): E395 - E402. [Abstract] [Full Text] [PDF]

				G. Wu, N. E. Flynn, D. A. Knabe, and L. A. Jaeger A cortisol surge mediates the enhanced polyamine synthesis in porcine enterocytes during weaning Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2000; 279(2): R554 - R559. [Abstract] [Full Text] [PDF]