Human and zebrafish IGFBP-6 inhibits blood vessel formation in zebrafish embryos in vivo. A) A 30 hour post fertilization (hpf) flk1:GFP transgenic zebrafish embryo. The upper panel is a bright field view and lower panel is a GFP view. Arrows indicate inner segmental vessels (ISV). B) 1-2 cell stage flk1:GFP transgenic zebrafish embryos were microinjected with phenol red, capped mRNA encoding human IGFBP-6, or zebrafish IGFBP-6 (zIGFBP-6b). The embryos were raised to 30 hpf and the number of inner segmental vessels (ISV) was counted. Results are expressed as a percentage of control (mean ± SE, n=3, *, P<0.05; ***, P<0.001).