AJP - Gastrointestinal and Liver Physiology, Vol 255, Issue 1 132-G139, Copyright © 1988 by American Physiological Society
Autoradiographic analysis of hepatocytes in mirex-induced adaptive liver growth
D. Wilson and J. D. Yarbrough
Department of Biological Sciences, Mississippi State University, Mississippi 39762.
The relationships between [3H]thymidine incorporation into hepatocyte
nuclei, cell enlargement, and mitotic index were studied in intact (INT)
and adrenalectomized (ADX) mirex-dosed rats. In INT mirex-dosed rats the
sequence of events included the following: a biphasic response in nuclear
labeling of mononuclear hepatocytes with peaks at 48 and 66 h postmirex
dose, a peak in mitotic activity 66 h postmirex dose, and a significant
increase in binuclear hepatocyte size 48 h postmirex dose. In ADX
mirex-dosed rats the sequence of events included the following: a biphasic
response in nuclear labeling of mononuclear hepatocytes with peaks at 24
and 48 h postmirex dose, a peak in mitotic activity 60 h postmirex dose,
and a marginal increase in binuclear hepatocyte size 48 h postmirex dose.
Corticosterone supplements to ADX mirex-dosed rats significantly reduced
nuclear labeling of the mononuclear hepatocytes and increased the size of
binuclear hepatocytes to that observed in INT mirex-dosed rats. This study
demonstrates that adaptive liver growth consists of a hyperplastic response
that involves mononuclear hepatocytes and a hypertrophic response that
involves binuclear hepatocytes. Both responses appear to be modulated by
corticosterone.
