Sites of action of drugs in stunting. The growth hormones (GH-RH) secreted by the hypothalamus (brain) will stimulate the growth of growth cartilage or conjugation cartilage at the bone extremities (epiphyses). These growth hormones will also stimulate the secretion of IGF-1 by the liver which will act on the one hand by stimulation on the growth cartilage and on the other hand by negative retrocontrol on the antehypophysis (window under the brain) and the hypothalamus. In the background, the histological structure of the growth cartilage with below the zone of endochondral osteogenesis (dark blue), hypertrophic zone (purple), growth cartilage (pink) and epiphyseal cartilage at the top (light blue)