- Glucose-dependent insulinotropic polypeptide is expressed in adult hippocampus and induces progenitor cell proliferation. Nyberg, J., Anderson, M.F., Meister, B., Alborn, A.M., Ström, A.K., Brederlau, A., Illerskog, A.C., Nilsson, O., Kieffer, T.J., Hietala, M.A., Ricksten, A., Eriksson, P.S. J. Neurosci. (2005)