The autoradiographic localization of adenylate cyclase in rat kidney using [ 3H]forskolin

The localization of [ 3H]forskolin binding to microscope slide mounted sections of rat kidney has been examined using autoradiography. Saturation studies showed [ 3H]forskolin binding to two sites, a high affinity site ( K D = 8.7 nM, B max = 0.14 pmol/mg protein) and a low affinity site ( K D = 6.7 μM, B max = 11.0 pmol/mg protein). Autoradiographs showed high affinity binding (thought to identify stimulatory guanine nucleotide binding protein (Gs)-linked adenylate cyclase) to all renal structures known to possess hormone sensitive adenylate cyclase, including all tubular segments, glomeruli and blood vessels. High concentrations of binding were associated with a portion of the proximal tubule and with papillary collecting tubules and ducts.