Cobalt chloride enhances sVEGFR-1 production from monocytes stimulated with GM-CSF. (A) Human peripheral blood monocytes were stimulated with 100 ng/mL GM-CSF in the presence or absence of 100μM CoCl₂. Cell-free culture supernatants were harvested at 48 hours, and sVEGFR-1 content was determined by ELISA. Data are mean ± SEM of 7 normal donors. (B) VEGF levels under the same conditions as in panel A.