Autoradiographic analysis of hepatocytes in mirex-induced adaptive liver growth.
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.
Wilson
D
D
Department of Biological Sciences, Mississippi State University, Mississippi 39762.
Yarbrough
J D
JD
D000222:Adaptation, Physiological; D000315:Adrenalectomy; D000818:Animals; D001345:Autoradiography; D003345:Corticosterone / Q000494:pharmacology; D007306:Insecticides / Q000494:pharmacology*; D008099:Liver / Q000254:growth & development*; D008297:Male; D008917:Mirex / Q000494:pharmacology*; D008940:Mitotic Index; D051381:Rats; D011919:Rats, Inbred Strains; D013936:Thymidine / Q000378:metabolism
D007306:Insecticides; D013936:Thymidine; D003345:Corticosterone; D008917:Mirex