alpha-1A Adrenergic R/ADRA1A: ProductsAlpha-1-adrenergic receptors (alpha-1-ARs) are members of the G protein-coupled receptor superfamily. They activate mitogenic responses and regulate growth and proliferation of many cells. There are 3 alpha-1-AR subtypes: alpha-1A, -1B and -1D, all of which signal through the Gq/11 family of G proteins. These various subtypes show different patterns of activation. ADRA1A encodes the alpha-1A-adrenergic receptor. ADRA1A is expressed in heart, brain, liver and prostate, but not in kidney, lung, adrenal, aorta and pituitary.