- The human Na+-taurocholate cotransporting polypeptide gene is activated by glucocorticoid receptor and peroxisome proliferator-activated receptor-gamma coactivator-1alpha, and suppressed by bile acids via a small heterodimer partner-dependent mechanism. Eloranta, J.J., Jung, D., Kullak-Ublick, G.A. Mol. Endocrinol. (2006)