Effects of calcium-regulating hormones and drugs on human monocyte chemiluminescence

Chemiluminescence (CL) associated with phagocytosing monocytes has been used as an index of the oxygen dependent metabolic activity of these cells. Because of the relationships between monocytes and cells involved in bone resorption, we studied the effects on human monocyte CL of hormones and drugs active in mineral metabolism. Two-hour preincubations of monocytes with human PTH-(1-34), bovine PTH, or prostaglandin E2 caused significant decreases in peak CL during phagocytosis stimulated by the addition of latex particles. Similar studies with dichloromethylene diphosphonate, ethane hydroxydiphosphonate, or salmon calcitonin (sCT) caused significant increases in CL, whereas preincubation with human CT at the same molar concentration did not. CL was also decreased after preincubations with methylprednisolone or bacterial endotoxin. The effect of bovine PTH was dose dependent to concentrations as low as 10 ng/ml, was not fully present after a shorter 1-min preincubation with the hormone, and differed in an otherwise identical system using polymorphonuclear leukocytes instead of monocytes. The production of hydrogen peroxide by phagocytosing monocytes was also significantly affected by each of the drugs and hormones. The direction and magnitude of these changes were similar to those in CL experiments, except for the effects of sCT. These studies relate the oxygen-dependent function of phagocytes to mediators of bone resorption and provide a new system for studying the effects of hormones and drugs on the cellular elements of bone and blood.