The angiogenic growth factors present in the bovine adrenal gland have been purified by a combination of differential salt precipitation, ion exchange chromatography, and heparin-Sepharose chromatography. They consist of 2 single chain polypeptides with apparent mol wt of 16,000 and 15,000. Sequence analysis of the first 14 residues of both peptides identified the sequences as Pro-Ala-Leu-Pro-Glu-Asp-Gly-Gly-Ser-Gly-Ala-Phe-Pro-Pro for 1 of the peptides and His-Phe-Lys-Asp-Pro-Lys-Arg-Leu-Tyr-x-Lys-Asn-Gly-Gly for the other. The first sequence is identical to residues 1-14 of bovine pituitary and brain fibroblast growth factor (FGF), while the second is identical to residues 1-14 of the corpus luteum (CL) FGF, which is an amino-terminally truncated form of FGF and is otherwise similar, if not identical, to FGF. The biological activity of adrenal FGF is indistinguishable from that of pituitary or brain FGF and CL FGF. They are highly active in triggering the proliferation of culture bovine vascular endothelial cells derived from either large vessels (aortic arch) or CL and adrenal cortex capillaries (half-maximal stimulation at 20-40 pg/ml and saturation at 400-600 pg/ml). In vivo implants containing 50 ng to 1 microgram adrenal-derived growth factors stimulate neovascularization in the chorioallantoic membrane of the chick embryo. In addition to being mitogenic for vascular endothelial cells, adrenal FGFs stimulate the proliferation of a wide variety of mesoderm- and neuroectoderm-derived cells, including vascular smooth muscle cells, granulosa and adrenal cortex cells, rabbit costal chondrocytes, and corneal endothelial cells.