TRANSFORMING GROWTH-FACTOR-BETA-1 AND PARATHYROID HORMONE-RELATED PROTEIN CONTROL THE SECRETION OF DIPEPTIDYL PEPTIDASE-II BY RAT ASTROCYTES

Meninges synthesize parathyroid hormone-related protein (PTHrP) and tr ansforming growth factor (TGF beta 1). Both factors control the activi ty of the glial enzyme dipeptidyl peptidase II (DPP II): TGF beta 1 in duces the secretion of enzyme activity by cultivated astrocytes in a d ose dependent manner. The maximal effect is achieved with a concentrat ion of 10 ng/ml and is dependent on the time of incubation. PTHrP itse lf has no effect on the release of DPP II activity but considerably re duces the effect of TGF beta 1. It is assumed that DPP II influences t he course of cicatrization after penetrating injuries of the brain and thus, meninges control glial scarring by the release of TGF beta 1 an d PTHrP.