Summary of the major signalling pathways used by the LepRb in the hypothalamus to regulate metabolic and reproductive function. See text for explanatory details. AGRP, agouti-related peptide; Akt is also known as protein kinase B; AMPK, adenosine monophosphate-activated protein kinase; CARTPT, cocaine- and amphetamine-regulated transcript prepropeptide; CREB, cAMP response element binding protein; CRTC, CREB-regulated transcriptional coactivator; ERK, extracellular signal-regulated kinase; FOXO1, forkhead box protein O1; Grb2, growth factor receptor-bound protein 2; InsR, insulin receptor; IRS, insulin receptor substrate; IRS4, insulin receptor substrate 4; JAK2, Janus kinase 2; KISS1, kisspeptin gene; LepRb, long form of the leptin receptor; mTOR, mammalian target of rapamycin; NPY, neuropeptide Y; PDK1, phosphatidylinositol-dependent protein kinase 1; PI3K, phosphoinositide 3-kinase; PIP2, phosphatidylinositol 4,5-biphosphate; PIP3, phosphatidylinositol 3,4,5-triphosphate; POMC, pro-opiomelanocortin; PTEN, phosphatase and tensin homolog deleted on chromosome 10; PTP1B, protein tyrosine phosphatase 1B; PTPe, protein tyrosine phosphatase epsilon; RSK, p90 ribosomal S6 kinase; S6, ribosomal protein S6; S6K, p70 S6 kinase; SHP2, Src homology-2 domain-containing protein tyrosine phosphatase-2; SH2B1, Src homology-2 B adaptor protein 1; SOCS3, suppressor of cytokine signalling 3; STAT3 and STAT5, signal transducer and activator of transcript 3 and 5; TCPTP, T cell protein tyrosine phosphatase. The ‘?’ indicates a pathway for which there is only limited published support.