AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 5 709-G713, Copyright © 1986 by American Physiological Society
Effect of refeeding on polyamine biosynthesis in isolated enterocytes
L. R. Fitzpatrick, P. Wang, B. E. Eikenburg, M. K. Haddox and L. R. Johnson
Ornithine decarboxylase (ODC) activity has been found to be preferentially
associated with small intestinal villus cells rather than crypt cells in
the rat. In the present study, ODC, S-adenosylmethionine decarboxylase
(SAMDC), and polyamines were measured in isolated enterocytes to determine
which cell populations increased polyamine biosynthetic activity after
refeeding. Two hours following refeeding, significant increases in ODC were
observed in villus tip (10 times) and midvillus (20 times) enterocytes. No
increase in ODC activity was found in isolated crypt cells. A similar
pattern was observed for SAMDC. Enzyme activity increased in villus tip (2
times) and midvillus (27 times) cells but not in crypt enterocytes.
Putrescine contents were increased following refeeding in midvillus
enterocytes (P less than 0.05) and in crypt cells (P less than 0.05). The
accumulation of putrescine in midvillus cells occurs via ODC-induced
biosynthesis, whereas in crypt enterocytes it may be due to putrescine
uptake. The lack of induction of ODC and SAMDC in crypt enterocytes
following acute refeeding suggests these enzymes are apparently not
involved in the initiation of cell proliferation known to occur under this
condition.
