[Activation of phosphatidylinositol metabolism of corneal epithelial cells by platelet derived growth factor].
Numerous recent studies have found that the ubiquitous platelet-derived growth factor (PDGF) is central to the regulation of proliferative processes. PDGF's mitogenic effect in many cell types, for instance, is made possible by a receptor-mediated activation of phospholipase C, the key enzyme in the phosphatidylinositol (PI) turnover in membranes. Activation of the PI turnover then leads to an increase in the intracellular concentration of inositoltriphosphate (IP3), which functions as a second messenger and mobilizes cytosolic-free calcium from the endoplasmatic reticulum. The goal of the present study was to show that PDGF in corneal epithelial cells stimulates this transmembrane signal transmission system. Cell incubation was carried out on long-term cultures of rabbit corneal epithelial cells. IP3 was determined by ion-exchange chromatography, as described by Berridge et al. PDGF in nanomolar concentrations (5-50 ng/ml) was found to induce a dose-dependent rise in IP3, which peaked after 60 s. The maximum 300% increase in IP3 was accompanied by a pronounced rise in cytosolic-free calcium. These results show that PDGF can activate PI turnover in corneal epithelial cells.
Knorr
M
M
Universitäts-Augenklinik, Tübingen, Bundesrepublik Deutschland.
Steuhl
K P
KP
Dartsch
P
P
Thiel
H J
HJ
D000818:Animals; D002455:Cell Division / Q000502:physiology*; D003315:Cornea / Q000166:cytology*; D046508:Culture Techniques; D004847:Epithelial Cells; D010982:Platelet-Derived Growth Factor / Q000502:physiology*; D011817:Rabbits
D010982:Platelet-Derived Growth Factor
Aktivierung des Phosphatidylinositol-Metabolismus kornealer Epithelzellen durch Platelet-derived-growth factor (PDGF).