PRODUCTION OF HEPARIN-BINDING ENDOTHELIAL MITOGENS BY BOVINE UTERINE FIBROBLASTIC AND EPITHELIAL-CELLS

This study was conducted to determine whether early-passage cultures o f bovine endometrial fibroblastic (Fb, n = 7 uteri) and epithelial (Ep , n = 3 uteri) cells produce endothelial mitogens in vitro and to begi n characterization of these mitogens. Confluent cultures of Fb and Ep were incubated for 72 h in serum-free media, and the resulting conditi oned media (CM) were evaluated for effects on proliferation of bovine aortic endothelial cells. CM from these Fb cultures (n = 8) and Ep cul tures (n = 4) stimulated (147 +/- 10% (mean +/- SEM), p < 0.01, and 12 4 +/- 8%, p < 0.10, respectively) proliferation of endothelial cells c ompared with control (unconditioned) media. Most of the mitogenic acti vity of a sample of Fb CM and a sample of Ep CM from one individual ut erus bound to heparin-agarose, and each exhibited mio major peaks of a ctivity that eluted at 0.9-1.0 and 1.7-1.8 M NaCl; the Fb CM also exhi bited an additional heparin-binding peak eluting at 0-0.1 M NaCl. Pool ed Fb CM (n = 8 cultures from 7 animals) also contained mitogenic acti vity for endothelial cells that bound to heparin-agarose, but exhibite d three major peaks, eluting at 0.6, 1.1, and 1.8 M NaCl. Pooled Ep CM (n = 4 cultures from 3 animals) showed only one peak of mitogenic act ivity, which eluted at 0.9 M NaCl. Further characterization indicated that heat treatment reduced the activity of all heparin-binding Fb CM and Ep CM peaks, except the Fb CM peak eluting at 1.7 M NaCl. Trypsin reduced the activity of all peaks except one. Protein-A-purified antib ody against fibroblast growth factor 1 (FGF-1) had no or only a slight effect on the mitogenic activity of the peaks. Mitogenic activity of the Fb CM peak eluting at 0.6 M NaCl was reduced by antibody against F GF-2. Activity of the Fb CM and Ep CM peaks that eluted at 1.7-1.8 M N aCl also was immunoneutralized by antibody to FGF-2. These data demons trate that early passage cultures of endometrial Fb and Ep cells produ ce heparin-binding endothelial mitogens that appear to be immunologica lly related to FGF-2. These heparin-binding endothelial mitogens may i nfluence endometrial vascular growth.