Journal of Photosciences

Effects of Parathyroid Hormone on the Fluidity of the Plasma Membrane Vesicles of Cultured Osteoblasts

Volume 8(2001), 87-92 page

ÀúÀÚ: Jung Sook Kang

   8-3-87.pdf (96.4K)

Keywords: parathyroid hormone  membrane fluidity  osteoblasts  fluorescent probe technique


Intramolecular excimer formation of 1,3-di(1-pyrenyl)propane (Py-3-Py) and fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) were used to investigate the effects of parathyroid hormone (PTH) on the bulk bilayer fluidity of the plasma membrane vesicles isolated from cultured osteoblasts (OB-PMV). In a dose-dependent manner, rat PTH-(1-34) [rPTH-(1-34)] increased the excimer to monomer fluorescence intensity ratio (I /I) of Py-3-Py and decreased the anisotropy (r) of DPH in OB-PMV.
This indicates that PTH increased both the lateral and rotational diffusion of the probes in OB-PMV.
Selective quenching of DPH fluorescence by trinitrophenyl groups was utilized to examine the transbilayer fluidity asymmetry of OB-PMV.
The anisotropy, limiting anisotropy, and order parameter of DPH in the inner monolayer were 0.024, 0.032, and 0.062 greater than calculated for the outer monolayer of OB-PMV.
Selective quenching of DPH fluorescence by trinitrophenyl groups was also utilized to examine the transbilayer effects of PTH on the fluidity of OB-PMV.
rPTH-(1-34) had a greater fluidizing effect on the outer monolayer as compared to the inner monolayer of OB-PMV.
Thus, it has been proven that PTH exhibits a selective rather than nonselective fluidizing effect within transbilayer domains of OB-PMV.