Changes in membrane fatty acids and delta-9 desaturase in senescence accelerated (SAMP8) mouse hippocampus with aging

Senescence accelerated mice (SAMP8) exhibit age induced impairments such as loss of memory and learning disabilities by the age of 8 - 10 months. Anal ysis of hippocampus of SAMP8 mice revealed that delta 9-desaturase (Delta(9 )desaturase) activity reduced up to 44-50% with age. Correspondingly, level s of unsaturated fatty acids are also lowered in the aged animals approxima tely to the same level. RNase protection assay showed that Delta(9)specific message decreased similarly with age. As such a decrease is known to cause alterations in membrane fluidity and affect cellular signaling pathways, t hese results suggest that lowering of Delta(9)gene expression may be partly involved in age induced impairments.