Preheat oven to 425 degrees. In large bowl shift together flour, baking powder, salt and baking soda. Cut the shortening into the flour mixture. Until coarse crumbs form. Add the buttermilk, tossing with fork until a dough forms. Turn onto floured surface. Knead lightly a few times just until smooth,. Pat the dough to 3/4 inch thick and cut into biscuits. Bake until golden about 12 to 15 minutes. Serve hot.