Purification of enough numbers of circulating eosinophils is difficult because eosinophils account for less than 5% peripheral blood leukocytes. Human eosinophilic leukemia EoL-1 cells have been considered an in vitro source of eosinophils as they can differentiate into mature eosinophil-like cells when incubated with dibutyryl cAMP (dbcAMP) or butyric acid. In this study, the viability and phe...

Bovine oocytes cultured in control medium or in medium containing dibutyrylcyclic adenosine monophosphate (dbcAMP) or an inhibitor of cyclic nucleotide phosphodiesterase (3-isobutyl-1-methylxanthine, IBMX) undergo germinal vesicle breakdown (GVBD). On the other hand, mouse oocytes remain arrested at the germinal vesicle (GV) stage when dbcAMP or IBMX is present. When 1 bovine GV stage oocyte is...

serum and, while dibutyryl cyclic AMP (dbcAMP) caused a marked stimulation of progesterone production in complete serum, it had only a small effect in LPDS. Lowdensity lipoprotein (LDL) and high-density lipoprotein (HDL) increased basal and dbcAMP-stimulated progesterone production. Cells were 7 times more sensitive to LDL than HDL although the maximum response to both lipoproteins did not diff...

The relation between myocardial tissue cyclic AMP (cAMP) and the vulnerability to ventricular fibrillation was assessed in the isolated perfused rat heart by measurement of ventricular fibrillation threshold (VFT) and vulnerable period duration (VP). Exogenous dibutyryl cyclic AMP (DBcAMP) reduced VFT and increased VP by a concentration-related action whereas exogenous cAMP did not. Theophyllin...

Cholera toxin and other bacterial toxins can induce electrogenic chloride (Cl) secretion in the small intestine resulting in secretory diarrhoea, when the colonic water reabsorption capacity is overwhelmed. The mechanism underlying this phenomena is that, these toxins increase intracellular cGMP and/or cAMP level through activation of guanylyl and adenylyl cyclase leading to the phosphorylation...

As a test of the hypothesis that cyclic nucleotides play a role in the regulation of retinomotor movements and disc shedding in the photoreceptor-pigment epithelial complex, we have used an in vitro eyecup preparation that sustains both disc shedding and cone retinomotor movements, Eyecups were prepared in white light from animals in which both shedding and cone movement had been blocked by 4 d...

We studied the molecular events set into motion by stimulation of D(1)-like receptors downstream of Na(+)-K(+)-ATPase, while measuring apical-to-basal ouabain-sensitive, amphotericin B-induced increases in short-circuit current in opossum kidney (OK) cells. The D(1)-like receptor agonist SKF-38393 decreased Na(+)-K(+)-ATPase activity (IC(50), 130 nM). This effect was prevented by the D(1)-like ...

Neurotrophin (NT)-driven differentiation is a process involving activation of multiple signalling events. Treatment of PC12 cells with the prototypic NT nerve growth factor (NGF) induces PC12 cell differentiation characterized by neurite outgrowth and expression of differentiation genes. Cyclic AMP (cAMP), one of the second messengers of NGF stimulation, has also been observed to induce neurona...

In this report we provide evidence for the activation of distinct dif ferentiation pathways during treatment of the neuroblastoma cell line SMS-KCNR with 1 mm dibutyryl cyclic AMP (dbcAMP) and/or 5 MM retinole acid (RA). Our results show that the adrenal gland specific gene pG2 is induced only during dbcAMP treatment, while RA induces a neuronal phenotype and expression of all neural related ge...

The clonal rat pheochromocytoma, PC12, responds to nerve growth factor (NGF) and dibutyryl adenosine cyclic 3':5'monophosphate (dbc AMP) by the elevation of cellular protein and RNA levels in all three parameters that are additive or greater than the sum of those caused by either agent alone, indicating that the mechanisms by which the two agents act to produce these changes are distinct. The c...