Gastrin and epidermal growth factor induction of ornithine decarboxylase in rat colonic explants.
An organ culture system was utilized to examine the effect of gastrin (G-17-I) and epidermal growth factor (EGF) on colonic mucosal ornithine decarboxylase (ODC) activity, and the expression of the ODC gene. Exposure of colonic mucosal explants to either gastrin or EGF (50-500 ng/ml) for only 4 h resulted in a profound stimulation (150-600%) in ODC activity over the basal level. These increases were essentially abolished by difluoromethylornithine (DFMO; 2 nmol/ml) or CaCl2 (2 umol/ml). Gastrin also activated the ODC gene in the colonic mucosa as evidenced by increased steady-state ODC mRNA levels in the colonic mucosal explants after 4 h exposure to the hormone, when compared with the controls. It is concluded that colonic mucosal ODC is responsive to both gastrin and EGF.
Arlow
F L
FL
Veterans Administration Medical Center, Allen Park, MI 48101.
Walczak
S M
SM
Moshier
J A
JA
Pietruk
T
T
Majumdar
A P
AP
D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology; D003106:Colon / Q000201:enzymology; D004790:Enzyme Induction; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005755:Gastrins / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D009924:Organ Culture Techniques; D009955:Ornithine Decarboxylase / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D011919:Rats, Inbred Strains
D005755:Gastrins; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; D009955:Ornithine Decarboxylase; D002122:Calcium Chloride