Calcium ionophore A23187 stimulates production of a 144 kDa gelatinase.

To determine whether intracellular calcium could be involved in regulating gelatinase production, bovine synovial fibroblasts were incubated with the calcium ionophores A23187 or ionomycin. Addition of calcium ionophore stimulated production of a gelatinase with an apparent molecular weight of 144 kDa. To ensure that the calcium ionophore was elevating cytosolic free calcium levels, calcium levels were determined using Indo-1. Addition of 0.1 microM ionomycin raised [Ca2+]i up to 1053 +/- 163 nM (mean +/- SD). Our data shows that calcium ionophore A23187 stimulates production of a high molecular weight gelatinase. The appearance of p144 gelatinase correlates with an increase in intracellular calcium.