Forskolin-insensitive adenylate cyclase in cultured cells of Choristoneurafumiferana (Insecta)

Abstract Adenylate cyclase from a spruce budworm cell line, IBRI-Cf1, is activated by octopamine (K a = 50 μM), guanine nucleotides and sodium fluoride but not by forskolin. In addition, forskolin does not potentiate the octopamine-sensitive response. To our knowledge, this is the first published report of a hormone-sensitive adenylate cyclase, with a functional guanine nucleotide regulatory protein, that is insensitive to forskolin both in intact cells and washed membrane preparations.