Consistent with this idea, in rats both subcutaneous injection of insulin and hypothalamic insulin implants during the postnatal period are sufficient to induce lifelong morphological remodelling of hypothalamic nuclei, including a reduction of neuronal density in the ventromedial hypothalamus, that is associated with later obesity (Harder et al. 1998, Plagemann et al. 1999). The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.