Two enzymes displaying cyclic GMP-stimulated cyclic AMP phosphodiesterase activity were purified from rat liver to apparent homogeneity: a 'particulate enzyme' found as an integral membrane protein associated with the plasma membrane, and a 'soluble' enzyme found in the cytosol. The physical properties of these enzymes were very similar, being dimers of Mr 134,000, composed in each instance of ...

The present studies were undertaken to determine the role, if any, of cyclic 3',5'-adenosine monophosphate (cyclic AMP) as a chemical inducer of rat liver alkaline phosphatase. Cholera enterotoxin, given intravenously to rats, led to a rapid rise in the activity of hepatic adenyl cyclase that was 7(1/2) times greater than control values in 6 h. Cyclic AMP levels were also significantly increase...

The extracellular concentration of cyclic adenosine 3',5'-monophosphate (AMP) of three different strains of Vibrio cholerae growing in syncase medium were measured. Cyclic AMP secreted by V. cholerae 569B varied widely, with different carbon sources. Mutant 13, which produced little or no toxin, released half the amount of cyclic AMP as the wild type. The release of less cyclic AMP into the med...

Cells from the pseudoplasmodial stage of Dictyostelium discoideum differentiation were dispersed and separated on Percoll gradients into prestalk and prespore cells. The requirements for stalk cell formation in low-density monolayers from the two cell types were determined. The isolated prespore cells required both the Differentiation Inducing Factor (DIF) and cyclic AMP for stalk cell formatio...

A protein kinase has been purified from the bovine corpus luteum by acid precipitation, ammonium sulfate fractionation and chromatography on DEAE-cellulose and hydroxylapatite columns. The enzyme has a molecular weight of approximately 159,000. DEAE-cellulose chromatography resolved the protein kinase activity into two peaks, designated as KI and KII. Both peaks possessed adenosine 3’,5’-monoph...

Cyclic AMP (adenosine 3',5'-monophosphate or cyclic adenylate) has now been established as a second messenger mediating many of the effects of a variety of hormones. Severial of the metabolic effects mediated by cyclic AMP are discussed, and it is suggested that certain other ("functional" or "mechanical") hormonal effects may be similarly mediated. In particular, the evidence presented support...

The 4-chlorophenylthio analogue of cyclic AMP evoked profound and long-lasting changes in cytosolic [Ca2+] ([Ca2+]i) in pituitary-derived GH3 cells. However, vasoactive intestinal peptide (VIP), a hormone considered to act via cyclic AMP, was ineffective in modulating [Ca2+]i. The ability of VIP to modulate [Ca2+]i was enhanced by treatments that increased intracellular cyclic AMP. Much greater...

Isoproterenol stimulates cellular accumulation of cyclic adenosine 3':5'-monophosphate (cyclic AMP) and produces a 2- to 4-fold increase in bidirectional potassium fluxes in turkey erythrocytes. Ouabain, which does not alter catecholamine-stimulated cellular cyclic AMP, inhibits potassium influx by 50 to 70%, does not alter potassium outflux or isoproterenol-stimulated potassium influx, but inc...

Adenosine-3',5'-cyclic phosphate (cyclic AMP) is absolutely required for flagella formation and, hence, motility in cyclic AMP-deficient mutants of Escherichia coli and Salmonella typhimurium.

The concentration of cyclic AMP within cells is regulated by the activities of adenylyl cyclases and phosphodiesterases (PDE) and the receptors and G proteins that modulate their activities. The extent to which cyclic AMP accumulates in a given cell and activates protein kinase A (PKA) is subject to tight transcriptional and post-transcriptional autoregulation (Table 1). For example, cyclic AMP...