Induction of heme oxygenase in intestinal epithelial cells: studies in Caco-2 cell cultures.
Enterally administered, heme is a good source of iron in humans and other animals, but the metabolism of heme by enterocytes has not been fully characterized. Caco-2 cells in culture provide a useful model for studying cells that resemble small intestinal epithelium, both morphologically and functionally. In this paper we show that heme oxygenase, the rate-controlling enzyme of heme catabolism, is present in abundance in Caco-2 cells, and that levels of its mRNA and activity can be increased by exposure of the cells to heme or metal ions (cadmium, cobalt). Caco-2 cells also contain biliverdin reductase activity which, in the basal state, is similar to that of heme oxygenase (approximately 40 pmole of product per mg protein per minute); however, when heme oxygenase is induced, biliverdin reductase may become rate-limiting for bilirubin production.
Cable
J W
JW
Department of Medicine, University of Massachusetts Medical School, Worcester 01655.
Cable
E E
EE
Bonkovsky
H L
HL
D004790:Enzyme Induction; D004847:Epithelial Cells; D004848:Epithelium / Q000201:enzymology; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D006801:Humans; D007422:Intestines / Q000166:cytology / Q000201:enzymology*; D014407:Tumor Cells, Cultured
D006419:Heme Oxygenase (Decyclizing)