Age-dependence of the lateral mobility of proteins in the plasma membrane of hepatocytes of C57BL/6 mice: FRAP studies on liver smears.
Protein lateral diffusion in hepatocyte membranes was measured in 23 male and 16 female C57BL/6 mice in four groups of age 5 to 32 months by means of fluorescence recovery after photobleaching (FRAP). The peroxide-induced autofluorescence (PIAF) in H2O2 treated liver smears is due to the oxidation of flavins bound uniformly to all proteins of the cell membrane, i.e., an average lateral diffusion constant (D) of those proteins can be measured. D showed a negative linear age-correlation in both sexes: D male = (2.81 - 0.016X)10(-10), and D female = (2.67 - 0.020X)10(-10) cm2/sec, (r greater than 0.94), where X is the age in months. Sex differences are significant (p less than .001) in the intercept. Fractional recovery did not prove to be age-dependent; it was, on average, 91% in males and 100% in females. The findings agree well with the previously obtained data on Fischer 344 and Wistar rats, and strengthen the gerontological relevance of D.
Zs-Nagy
I
I
First Laboratory of Clinical Physiology, Tokyo Metropolitan Institute of Gerontology, Japan.
Kitani
K
K
Ohta
M
M
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D002463:Cell Membrane Permeability; D003720:Densitometry; D005260:Female; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D051381:Rats; D011916:Rats, Inbred F344; D011919:Rats, Inbred Strains; D012737:Sex Factors; D013045:Species Specificity
D008565:Membrane Proteins