Overview General mechanism releasing hormone (IP3) → pituitary hormone (cAMP) → systemic hormone (steroid) GnRH → FSH/LH → estrogen/testosterone/progesterone TRH → TSH →T3/T4 vasoactive hormones cGMP growth factors tyrosine kinase MAP kinase growth hormone, cytokines, hormones receptor tyrosine kinase JAK/STAT Endocrine Hormones IP3 cAMP cGMP Tyrosine Kinase (MAP Kinase) Non Receptor Tyrosine Kinase - (JAK/STAT) Steroid GnRH FSH ANP Insulin Prolactin Glucocorticoid Gastrin LH NO (EDRF) IGF-1 Immunomodulators (IL-2,6, and IFN) Estrogen Oxytocin ACTH FGF GH Progesterone TRH TSH PDGF G-CSF Testosterone ADH (V1) CRH EGF Erythropoietin Aldosterone Histamine (H1) hCG Thrombopoietin Vitamin D Angiotensin II PTH T3/T4 Calcitonin Cortisol Glucagon GHRH (can act via IP3as well)