NPPA and adrenal cortex carcinoma: The proposed structural model of the MGC purified from rat adrenocortical carcinoma (Paul and Sharma, 1985; Paul, 1986; Paul et al., 1987; Sharma et al., 1988a; Sharma and Duda, 2014b) and later from the rat adrenal cortex (Takayanagi et al., 1987a,b; Meloche et al., 1988) established that it is a receptor for atrial natriuretic factor (ANF); and, it is a three component transduction system, all components embodied in one protein.