Interation of cyclic AMP with a profoundly changing pattern of specific binding proteins was shown during aerobic germination of sporangiospores from the fungus Mucor racemosus. 32P-labeled 8-azido-cycli AMP, an analogue of cyclic AMP that forms a covalent linkage with the binding proteins under u.v. light, was used as the ligand. Binding proteins carrying this photoaffinity label were separate...

The distribution of protein kinases activated specifically by low concentrations of guanosine 3’,5’-monophosphate (cyclic GMP) or adenosine 3’,5’-monophosphate (cyclic AMP) in various tissues and species of Arthropoda was studied. The Arthropoda were found to represent a rich source of cyclic GMP-dependent protein kinases. The relative levels of cyclic GMP-dependent and cyclic AMP-dependent pro...

The N6,02’-dibutyryl analogue of cyclic adenosine 3’,5’monophosphate (dibutyryl cyclic AMP) elevates the level of hepatic tyrosine-cr-ketoglutarate transaminase (L-tyrosine: 2-oxoglutarate aminotransferase, EC 2.6.1.5) some 3to 6-fold in intact and adrenalectomized rats. The response of this enzyme is more rapid to dibutyryl cyclic AMP than to any other inducer of the transaminase. Hourly injec...

Isolated rat kidneys were perfused with a recirculating medium containing exogenous adenosine 3':5'-monophosphate (cyclic AMP) or guanosine 3':5'-monophosphate (cyclic GMP) at an initial concentration of 0.1 mM. Both cyclic nucleotides were rapidly removed from the perfusate. Urinary excretion accounted for about 20% and 40% of the respective cyclic AMP and cyclic GMP lost from the perfusate. T...

Isolated rat kidneys were perfused with a recirculating medium containing exogenous adenosine 3’:5’-monophosphate (cyclic AMP) or guanosine 3’:5’-monophosphate (cyclic GMP) at an initial concentration of 0.1 IIIM. Both cyclic nucleotides were rapidly removed from the perfusate. Urinary excretion accounted for about 20% and 40% of the respective cyclic AMP and cyclic GMP lost from the perfusate....

The molecular events occurring at the level of the plasma membrane after insulin occupies its receptor remain an enigma. We can demonstrate that with purified rat liver plasma membranes the cyclic AMP phosphodiesterase activity (Marchmont & Houslay, 1980) can be increased some t t fo ld (at 0.4pM-CYCliC AMP) if the membranes are pretreated with bovine insulin (1OnM) together with cyclic AMP (0....

The relationship between mean fat cell size, maximal tissue cyclic AMP concentration, and glycerol release was investigated in human subcutaneous adipose tissue incubated in vitro with or without isoprenaline or noradrenaline added at maximal effective concentrations. Basal and stimulated glycerol release and cyclic AMP concentration were each related to the fat cell size. Whether or not the ph...

The second messenger molecule cyclic AMP dramatically modulates the apoptotic program in a wide variety of cells, accelerating apoptosis in some and delaying the rate of apoptosis in others. Human neutrophil apoptosis, a process that regulates the fate and numbers of these potentially histotoxic cells in inflammatory sites, is profoundly delayed by the cell-permeable analog of cyclic AMP, dibut...

Cytosolic cyclic AMP-binding capacity and cyclic AMP-dependent protein kinase activity have been studied in relation to differentiation and maturation of rabbit bone marrow erythroblasts. Using cells fractionated by velocity sedimentation at unit gravity, it was found that both activities decreased in dividing cells when calculated in terms of cell number but remained constant per cell volume. ...

Protein phosphorylation in intact S49 mouse lymphoma cells was studied by using high-resolution two-dimensional gel electrophoresis of proteins labelled with [35S]methionine or [32P]Pi. In wild-type cells substrates for cyclic AMP-stimulatable phosphorylation exhibited high basal phosphorylation; in mutant cells deficient in activities of either cyclic AMP-dependent protein kinase or adenylate ...