Schematic summary of the calcium-regulated pathway from PTH-mediated calcium reabsorption in the distal tubule to cAMP-regulated renin secretion into the afferent arteriolar lumen. Abbreviations and acronyms: AC-V = adenylyl cyclase isoform 5, Ca++ = (ionized free) calcium, cAMP = cyclic adenine monophosphate, CaSR = calcium-sensing receptor, ER = endoplasmic reticulum, H+ = hydrogen ion, JG = juxtaglomerular, NCX1= sodium/calcium exchanger- member 1, PMCA= plasma membrane Ca++ ATPase, PTH = Parathyroid hormone, PTH-R1 = parathyroid hormone type 1 receptor, PDE1c = phosphodiesterase isoform 1c, TRPV5= Transient receptor potential cation channel subfamily V member 5, (+) = stimulatory, and (−) = inhibitory action.