Peroxisome distribution along the crypt-villus axis of the guinea pig small intestine.
Peroxisomes and peroxisomal enzyme expression were investigated biochemically and morphometrically in guinea pig intestinal epithelial cells at different stages of their migration along the crypt-villus axis. Epithelial cells were sequentially isolated along the axis and the specific activities of the peroxisomal enzymes catalase and acyl-CoA oxidase were found to be significantly higher in differentiated and mature cells situated at the villus tip and stem than in the crypt. Conversely, 1-alk-1'enyl, 2-acyl phospholipid (plasmalogen) concentration in the crypt and middle villus was significantly higher than in villus tip cells. Assay of alkyl DHAP synthase and fatty acyl CoA reductase (enzymes responsible for the production of plasmalogen precursors) showed no correlating activity gradient with plasmalogen concentration. Morphometric analysis revealed that peroxisomes were present even in the most immature stem cells, however, their number and volume and surface densities increased as the epithelial cell developed as did the proportion of elongated and vermiform peroxisomes to spherical structures. Senescent cells at the tip of the villus, however, showed a dramatic decrease in number of peroxisomes per cell possibly due to cellular degradation. We conclude that the peroxisomal compartment of the guinea pig small intestinal epithelial cell develops as a function of cell development possibly reflecting adaptation to maximise its metabolic capacity.
Phipps
A N
AN
School of Biological Sciences, University of Manchester, UK.
Connock
M J
MJ
Johnson
P
P
Burdett
K
K
D000818:Animals; D006168:Guinea Pigs; D007413:Intestinal Mucosa / Q000378:metabolism / Q000648:ultrastructure; D007421:Intestine, Small / Q000378:metabolism / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D020675:Peroxisomes / Q000378:metabolism / Q000648:ultrastructure*