IGF1 and retinitis pigmentosa 1: In this regard, in the rd10 experimental mouse model of RP proinsulin delays the death of photoreceptors and prolongs visual function (Corrochano et al., 2008) and, importantly, IGF-1 also decreases apoptosis of photoreceptors in both genetic and experimentally induced RP models (Arroba et al., 2009).