Phosphoinositol (PIP2 ) DAG IP3 Activation of protein kinase C Release of intracellular Ca2+ Regulation of other enzymes (by protein phosphorylation) Regulation of other enzymes (by Ca2+) Vasopressin (ADH) : Induces vasoconstriction TSH : Induces the synthesis and release of a small amount of T4 Angiotensin II : Induces Aldosterone synthesis and release TRH : Induces the synthesis and release of TSH GnRH : Induces the synthesis and release of FSH and LH
• Activate G protein coupled Inward-Rectifying Potassium Channels (Kir , GIRK) • Activation of PLA2 when bound to histamine receptors • Activating PLC, as a minor mechanism of GHRH • Activation L-type calcium channels
of Gα associating Gβγ Allostrically Exchanging GTP/GDP -Regulator of G protein signalling (RGS) or GTPase-activating proteins (GAP) -GAP activity of Effector (PLC or AC)