Journal of Animal Science, Vol 72, Issue 4 969-975, Copyright © 1994 by American Society of Animal Science

JOURNAL ARTICLE

In situ binding and immunocytochemistry of insulin-like growth factor I receptors in primary cultures of porcine adipose tissue stromal vascular cells treated with indomethacin

R. L. Richardson, G. J. Hausman and J. T. Wright
Agricultural Research Service, USDA, Athens, GA 30163.

An autoradiographic technique for localizing [125I]IGF-I binding was adapted to primary cultures of pig stromal-vascular (S-V) cells to study the effects of pig serum (PS) and (or) indomethacin (Indo) on IGF-I and fibronectin (FN) receptors. Computer assisted image analysis revealed that the percentage of [125I]IGF-I binding decreased (P < .001) in cultures (7 d) treated with Indo compared with 2% PS alone. Binding of [125I]IGF-I analog (low-binding affinity for the IGF-I binding proteins) also decreased (P < .001) in 7-d cultures treated with Indo. The unlabeled IGF-I analog was more effective than unlabeled IGF-I at decreasing (P < .001) binding of [125I]IGF-I. Number of fat cell clusters and fat cell area (total lipid deposition) increased (P < .001) with PS + Indo compared with PS or Indo alone. Immunocytochemical staining (fluorescein isothiocyanate) of IGF-I receptors with a polyclonal antibody (flow cytometric analysis) decreased (P < .001) from 1 to d 3 and did not change from 3 to 7 d with PS alone. However, the percentage of reactive cells decreased (P < .05) when Indo was added to PS. In contrast, the number of cells detected with the FN receptor antibody increased fourfold (P < .01) from 1 to 7 d in cultures with PS alone and decreased (P < .05) when Indo was present. Undifferentiated cells around fat cell clusters were reactive for the IGF-I receptor, but fat cells showed no reactivity.(ABSTRACT TRUNCATED AT 250 WORDS)