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 transforming growth factor (TGF beta 1). Both factors control the activity of the glial enzyme dipeptidyl peptidase II (DPP II): TGF beta 1 induces the secretion of enzyme activity by cultivated astrocytes in a dose dependent manner. The maximal effect is achieved with a concentration of 10 ng/ml and is dependent on the time of incubation. PTHrP itself has no effect on the release of DPP II activity but considerably reduces the effect of TGF beta 1. It is assumed that DPP II influences the course of cicatrization after penetrating injuries of the brain and thus, meninges control glial scarring by the release of TGF beta 1 and PTHrP.