The continuing objectives of this research are to elucidate factors involved in regulating intestinal growth and differentiation and to delineate the regulatory mechanisms by which regulators exert their effects. To determine hormonal regulation of intestinal growth and maturation, infant rats will be hypophysectomized or adrenalectomized and artificially reared by isocaloric infusion of a hormone-free diet to serve as an in vivo model system. Using this model, the effects of hormones, including growth hormone, corticosterone, thyroxine and epidermal growth factor, alone or in various combinations on epithelial cell proliferation, migration and maturation will be determined. The criteria of cell proliferation, including cell cycle time (G-1, S, G-2 and M phases), crypt cell production rates and crypt cell population, will be determined by autoradiography after H-thymidine injection and by metaphase accumulation rates after vincristine administration. Decrease of lactase activity and appearance or increase of sucrase activity will be used as maturational markers. The differential effects of corticosterone and thyroxine on the de novo synthesis of sucrase-isomaltase (S-I) will be examined by the techniques of immunofluorescent staining, immunohistochemistry, rocket immunoelectrophoresis, isoelectric focusing, immunoblotting and in vitro mRNA translation. The defect in post-translational modification of S-I which is believed to lead to sucrose intolerance in human hormonal regulation on glycosylation of S-I will be studied by pulse-chase experiments with 35S-methionine, 14C-mannose and fucose. Catalytic activity and structural changes will be analyzed. The hormonal effect on intestinal development will also be examined in an in vitro system to determine: 1) the role of mesenchymal cells in epithelial growth and differentiation, 2) hormonal effect on the organization of contractile proteins and cell migration, and 3) the mechanism by which epithelial cell sorting, migration and organogenesis occur.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK033916-07
Application #
3232330
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1983-07-01
Project End
1991-08-31
Budget Start
1989-09-01
Budget End
1990-08-31
Support Year
7
Fiscal Year
1989
Total Cost
Indirect Cost
Name
St. Luke's-Roosevelt Institute for Health Science
Department
Type
DUNS #
City
New York
State
NY
Country
United States
Zip Code
10019
Yeh, K; Yeh, M; Holt, P R et al. (1994) Development and hormonal modulation of postnatal expression of intestinal alkaline phosphatase mRNA species and their encoded isoenzymes. Biochem J 301 ( Pt 3):893-9
Holt, P R; Yeh, K Y (1992) Effects of starvation and refeeding on jejunal disaccharidase activity. Dig Dis Sci 37:827-32
Yeh, K Y; Yeh, M; Pan, P C et al. (1991) Posttranslational cleavage of rat intestinal lactase occurs at the luminal side of the brush border membrane. Gastroenterology 101:312-8
Yeh, K Y; Yeh, M; Montgomery, R K et al. (1991) Cortisone and thyroxine modulate intestinal lactase and sucrase mRNA levels and activities in the suckling rat. Biochem Biophys Res Commun 180:174-80
Yeh, K Y; Yeh, M; Holt, P R (1991) Intestinal lactase expression and epithelial cell transit in hormone-treated suckling rats. Am J Physiol 260:G379-84
Yeh, K Y; Yeh, M; Holt, P R (1991) Thyroxine and cortisone cooperate to modulate postnatal intestinal enzyme differentiation in the rat. Am J Physiol 260:G371-8
Yeh, K Y; Yeh, M; Holt, P R (1989) Induction of rat jejunal epithelial cell expression of sucrase-isomaltase by glucocorticoids in primary cell culture and in vivo. Biol Cell 65:139-50
Yeh, K Y; Yeh, M; Holt, P R (1989) Induction of intestinal differentiation by systemic and not by luminal corticosterone in adrenalectomized rat pups. Endocrinology 124:1898-904
Yeh, K Y; Yeh, M; Holt, P R (1989) Differential effects of thyroxine and cortisone on jejunal sucrase expression in suckling rats. Am J Physiol 256:G604-12