Changes in microtubular tau protein after estrogen in a cultured human neuroblastoma cell line.

1. Cultured human SH-SY5Y neuroblastoma cells were used to determine whether 17-beta-estradiol affects the metabolism of microtubular tau protein. 2. After 24-hr treatment 17-beta-estradiol (10(-7) M) increased 50 kDa tau protein in the cytoplasmic (supernatant) fraction and decreased it in the membrane (pellet) fraction. 3. The increase in cytoplasmic tau was accompanied by increases in total protein in both cytoplasmic and membrane fractions, 50 and 70%, respectively. 4. The estrogen (10(-7) M) also caused a 31% reduction in the total number of cells.