Membrane fluidity in normal and cystic fibrosis fibroblasts.

We have observed distinct differences in the polarization of fluorescence and temperature 
dependent emission intensity of the highly fluoescent phospholipid derivative (1-acyl-2-(N-4-nitrobenzo-2-oxa-1,3-diazole)--aminocaproyl phosphatidylcholine 
(NBD-PC), when incorporated in the plasma membranes of normal and cystic 
fibrosis fibroblasts. Fluorescence polarization measurements indicate that the fluorochrome has a 
much higher degree of rotational mobility in cystic fibrosis fibroblasts as 
compared with normal cells. Temperature dependent transitions in the emission intensity 
of NBD-PC incorporated in normal fibroblasts are indicated at 17.7 and 
21.2 degrees C while the abnormal cell membranes apparently undergo transitions 
at 8.7 and 13.5 degrees C. These differences might be due 
to changes in plasma membrane composition and/or organization, in the case 
of the cystic fibrosis cells. 