title: Expression of DNase I in rat parotid gland and small intestine is regulated by starvation and refeeding.
abstract: DNase I in rats is mainly expressed in the parotid gland and the small intestine and functions as a digestive enzyme. Male Wistar rats were deprived of food for 48 h, refed with nonpurified diet for 2 h and killed at 0, 0.33, 0.67, 1, 2, 6 or 12 h. The activity and mRNA of DNase I in the parotid gland and the small intestine were determined. We found that in rats that were not fed for 48 h there was accumulation of DNase I in the parotid gland but not in the small intestine. In the parotid gland, refeeding decreased DNase I activity (P < 0.05), perhaps due to an increase in secretion. The increase in DNase I mRNA probably resulted from the need for protein synthesis. However, in the small intestine, both the enzyme activity and the amount of mRNA were up-regulated by refeeding (P < 0.05). Exposing rats to food in a sealed transparent flask also caused a 2.5-fold increase in DNase I mRNA within 30 min in the parotid gland. These data suggested that the expression of rat parotid DNase I is up-regulated by feeding and that mastication is not essential for the regulation.
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Shao-Chun
authors.initials: SC
authors.lastname: Lu
authors.forename: Chen-Hwang
authors.initials: CH
authors.lastname: Shih
authors.forename: Ta-Hsiu
authors.initials: TH
authors.lastname: Liao
mesh_terms: D000818:Animals; D003850:Deoxyribonuclease I / Q000378:metabolism*; D005502:Food; D007421:Intestine, Small / Q000201:enzymology*; D008297:Male; D010306:Parotid Gland / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D013217:Starvation / Q000378:metabolism*
chemical_list: D003850:Deoxyribonuclease I