Figure 8. Prolactin-dependent signal transduction pathways. Prolactin-activated beta-cell signalling in the presence of physiological glucose concentration (6 mM). Glc: glucose; Grb2: growth factor bound protein 2; JAK-2: janus kinase 2; MAPK: mitogen activated protein kinase; MEK: MAPK kinase; IGF-I: insulin like growth factor-I; IRS: insulin receptor substrate; PI3‘K: phosphatidylinositol 3‘ kinase; PKB: protein kinase B = AKT; PKC: protein kinase C; PKG: protein kinase G; Prl: prolactin; p70S6k: 70kD S6 kinase; Shc: SH2-containing protein; mSOS: murine sons of sevenless-1 protein; STAT-5: signal transducer and activator of transcription; mTOR: murine target of rapamycin.