Osteocalcin knockout mice exhibited glucose intolerance, increased fat mass, insulin resistance, decreased expression of insulin target genes in liver and muscle, and decreased adiponectin gene expression in adipose [11], while administration of recombinant osteocalcin increased insulin secretion, decreased blood glycaemia and weaken the development of obesity [12]. The gene discussed is BGLAP; the disease is obesity due to melanocortin 4 receptor deficiency.