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...

1. Endogenous cyclic AMP-stimulated phosphorylation of a 49700-Mr Wolfgram protein component in rabbit central nervous system was investigated by using photoaffinity labelling and 2',3'-cyclic nucleotide 3'-phosphodiesterase activity staining after electroblotting on to nitrocellulose paper. 2. Photoaffinity labelling with 8'azidoadenosine 3',5'-cyclic monophosphate showed a cyclic AMP-binding ...

Three protein kinases were separated from bovine epididymal spermatozoa by using DEAE-Sephadex ion exchange chromatography and Sephadex G-100 gel filtration. The molecular weights of these three kinases were estimated to be 120,000, 78,000 and 56,000 by the use of Sephadex G-100 gel filtration. The activity of all three kinases was greatly enhanced by cyclic adenosine 3’,5’-monophosphate (cycli...

Adenosine 3':5'-cyclic monophosphate (cyclic AMP) has been shown to have an antimitotic role in various cell types, and it has been hypothesized that a decrease of cyclic AMP concentration in the cell initiates or permits cell division. This hypothesis has been evaluated with respect to clonal proliferation of lymphocytes. Two potent mitogenic agents, phytohemagglutinin and concanavalin A, whic...

Epinephrine or carbachol, alone or together with parathyroid hormone (PTH) or calcitonin, was added into the incubation of young rat tibia and cyclic AMP as well as cyclic GMP in the tissue was determined. Epinephrine induced a dose related and rapid increase of cyclic AMP probably through mechanism different from that of PTH or calcitonin. The effect of these hormones to increase cyclic AMP wa...

Phosphodiesterase activities for adenosine and guanosine 3’ : 5’-monophosphates (cyclic AMP and cyclic GMP) were demonstrated in particulate and soluble fractions of rat anterior pituitary gland. Both fractions contained higher activity for cyclic GMP hydrolysis than that for cyclic AMP hydrolysis when these activities were assayed at subsaturating substrate concentrations. Addition of protein ...

Both cholera enterotoxin and certain prostaglandins have been shown to stimulate intestinal fluid secretion in vivo, to cause ion flux changes in vitro similar to those caused by addition of cyclic 3',5'-adenosine monophosphate (cyclic AMP), and to activate intestinal mucosal adenyl cyclase. It has been suggested that the effects of the enterotoxin on intestinal cyclic AMP metabolism may be ind...

The solubilization of plasma membrane fractions FI and FII associated protein kinases has been attempted using monovalent salts of high ionic strength and various detergent treatments. Extraction of FI and FII plasma membranes with high ionic strength salt solutions did not release more than 20% of the protein kinase activity. Similarly, monovalent salts released little adenosine 3':5'-monophos...

1. The effects of adrenalectomy on the adenylate cyclase--adenosine 3':5'-cyclic monophosphate (cyclic AMP) system of rat renal medulla were examined to evaluate the mechanism of the impaired water diuresis in glucocorticoid deficiency. 2. Concentrations of cyclic AMP in medullary tubules from adrenalectomized rats were significantly higher than in the tubules from control animals both in the p...

Cyclic adenosine 3':5'-monophosphate (cyclic AMP) levels were slightly increased in preleukemic AKR mouse thymus cells, compared with nonleukemic thymus cells, but were markedly reduced in leukemic cells. Adenylate cyclase activity rose during the preleukemic and leukemic phases of leukemogenesis. Although the drop of epinephrine-induced stimulation of thymus adenylate cyclase in the preleukemi...