INFLUENCE OF FOLLICULAR MATURATION ON THE SUSCEPTIBILITY OF CHICKEN OVARIAN GRANULOSA-CELLS TO FREE OXYGEN RADICALS

The influence of ovarian follicular maturation on lipid peroxidation-i nduced changes in the fluidity of plasma membrane of granulosa cells w as investigated using the fluorogenic polyunsaturated fatty acid cis-p arinaric acid (cPNA). An increase in lipid peroxidation results in the decrease of fluorescence intensity of cPNA. A decrease in membrane fl uidity results in the decrease of fluorescence polarization of cPNA. G ranulosa cells isolated from the largest (F1; mature), and third lar e st (F3; developing) preovulatory follicles as well as from a pool of i mmature small yellow follicles (SYF) of the domestic hen ovary were pr e-labelled with cPNA. The cPNA-labelled cells were exposed to a free o xygen radical generating agent 2,2'azobis (2-amidinopropane)-hydrochlo ride (AAPH). AAPH enhanced the rate of decrease in fluorescence intens ity of cPNA-labelled cells. This effect of AAPH was greater in the mor e differentiated granulosa cells obtained from mature follicles than i n less diferentiated cells isolated from immature follicles. Similarly , the degree of change in fluorescence polarization was greater in mor e differentiated F1 granulosa cells than in the less differentiated on es. The analysis of fatty acid composition of phospholipids indicated that the plasma membrane of differentiated granulosa cells contained a higher proportion of the unsaturated fatty acids, oleic and linoleic acids. The fluorescence data show that the rigidity of the plasma memb rane of chicken granulosa cells decreases with advancing follicular ma turation presumably due to relative increase in the unsaturated fatty acid content of plasma membrane phospholipid. (C) 1997 Elsevier Scienc e Inc.