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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of cholera on adrenal weight in hypophysectomized rats were investigated, in an attempt to demonstrate an ACTH-like, adrenal trophic effect of the toxin. The results suggested that the toxin probably exerts is ACTH-like action on the adrenal via adenylate cyclase. Cholera toxin was also shown to have a thermolytic action, similar to that of ACTH, probably due to stimulation of adrenal glucocorticoid secretion.
Mol Cell Endocrinol
PMID:The effects of cholera toxin on the adrenal weight in hypophysectomized rats. 18 72

The effects of cholera toxin on the responses of cultured Sertoli cells were compared with those elicited by follicle-stimulating hormone (FSH), and N6O2'-dibutyryl-3',5'-cyclic AMP (bu2cAMP). Addition of FSH or cholera toxin increased cAMP levels. Subsequently there was greater rates of conversion of testosterone to 17beta-estradiol, formation of androgen-binding protein (ABP), and incorporation of [3H]thymidine into DNA by Sertoli cells prepared from testes of immature rats and cultured in the presence of either FSH or cholera toxin. Addition of bu2-cAMP also resulted in enhanced rates of formation of ABP, synthesis of 17beta-estradiol and synthesis of DNA. Cholera toxin and bu2-cAMP elicited changes in morphology of cultured Sertoli cells indistinguishable from those following FSH addition. It is concluded that elevated intracellular cAMP levels can duplicate known actions of FSH on cultured Sertoli cells, but the possible obligatory role of cAMP in mediating FSH actions remains to be evaluated.
Mol Cell Endocrinol
PMID:Similarity of responses of cultured Sertoli cells to cholera toxin and FSH. 18 80

A large number of hormones and neurotransmitters activate adenylyl cyclase [ATP, pyrophosphate lyase (cyclizing; EC 4.6.1.1.)] catalyzing the formation of cAMP and PPi from ATP in the presence of Mg2+. The cAMP formed is in turn responsible for eliciting the physiological responses of these hormones and neurotransmitters. In addition to hormones and neurotransmitters, fluoride ion, cholera toxin and guanyl nucleotides (GTP and GTP analogs such as GTP gamma S and GMP-P(NH)P) also stimulate adenylyl cyclase activity (Perkins, 1974; Birnbaumer, 1977; Gill, 1977). It has become evident that hormonally-responsive adenylyl cyclase is a multi-component system consisting of at least 3 physically distinct units. The first is the hormone receptor containing a specific site for a given hormone. The second is the catalytic moiety (C component) of adenylyl cyclase bearing the site responsible for catalysis of the cyclizing reaction. The third is the guanyl nucleotide regulatory subunit (G component) which binds guanyl nucleotide. Recently, a GTPase activity has been found to be associated with the G component of adenylyl cyclase (Cassel and Selinger, 1976; Cassel et al., 1977a, b; Lambert et al., 1979). In this review we will present information on the regulation of hormonally-responsive adenylyl cyclases. This is not intended to be a comprehensive review of the literature. Rather, it represents our views on the current status of the regulation of cAMP formation.
Mol Cell Endocrinol 1979 Dec
PMID:Guanyl nucleotide regulation of hormonally-responsive adenylyl cyclases. 23 Jan 2

Improved Vibrio cholerae donors were constructed by introducing the ampicillin transposon, Tn1, into both the conjugative plasmid, P, and the bacterial chromosome to provide "portable regions of homology." The resulting Tfr (Transposon-facilitated recombination) donors transferred genes at high frequency from origins specified by the chromosomally inserted Tn1 copies. Tn1 was transposed into the chromosome from a deleted P::Tn1 vector, which was eliminated from the cells by superinfection with a thermosensitive P::Tn9 (chloramphenicol) mutant plasmid. After eliminating the thermosensitive plasmid, the chromosomally resistant isolates were converted into donors with a P::Tn1 conjugative plasmid. Tfr donors were also obtained by isolating Tn1 insertion mutations in a gene for thymine biosynthesis. Chromosomal sites of Tn1 relative to bacterial genes were determined by measuring gene transfer frequencies and genetic linkage. In one case, linkage of the amp gene to the chromosomal genes that defined its location was demonstrated. Chromosomal transfer by Tfr donors was reversed by isolating P::Tn1 plasmids that contained Tn1 inserted in the opposite orientation.
Mol Gen Genet 1979 Feb 16
PMID:Transposon-facilitated recombination in Vibrio cholerae. 28 48

A comparative study of termostability of microorganisms DNA was performed in order to increase the resolution of the method of molecular hybridization. Molecular hybridization was carried out and the curve of hybrid DNA duplexes distribution, acccording to termostability of two groups of microorganisms, related to strains Echerichia coli B1 and Vibrio cholerae eltor 18647, were obtained. It was determined that the form of the curves is specie specific for the microorganisms investigated but there exists a similarity between the closely related strains which can not be distinguished by the percent of homology.
Mol Biol (Mosk)
PMID:[Analysis of the thermostability of the hybrid DNA molecules of microorganisms as a means of increasing the resolution of the molecular hybridization technic]. 35 65

1. A whole-gut perfusion technique has been used to compare the rates of intestinal absorption of sodium and xenon. 2. The calculated transit-time spectra for sodium and xenon across the gut mucosa do not differ significantly either in mean transit time or, for the first 15 min, in shape. 3. These results support the hypothesis that the rate of transfer of sodium from the small intestinal lumen to plasma is limited by blood flow. 4. It is suggested that some features of cholera can be explained by the hypothesis.
Clin Sci Mol Med 1977 Mar
PMID:The relative transfer rates for sodium and xenon from gut lumen to plasma in man. 84 55

1. Duodeno-jejunal intestinal loops in rats were perfused with cholera toxin and the pancreatic and biliary secretory responses studied. 2. Intraluminal cholera toxin induced a significant flow of pancreatic and biliary fluid and sustained protein (enzyme) secretion in pancreatic juice, in addition to the expected stimulation of mucosal secretion. 3. Intravenously injected cholera toxin failed to elicit a secretory flow from the pancreas and biliary tract. 4. The time-course of the enhanced secretory flow from pancreas and biliary tract after intraluminal cholera toxin corresponds closely to the secretion of intestinal fluid. 5. The results of these studies provide evidence of sustained stimulation of pancreatic and biliary secretions after mucosal exposure to cholera toxin. These observations support the suggestion that secretion from the pancreas and liver may significantly contribute to the total intestinal secretion in cholera.
Clin Sci Mol Med 1976 Jul
PMID:Stimulated flow of pancreatic and biliary secretions after intestinal exposure to cholera toxin. 93 69

The ability of cations to modulate the binding of the sigma 1 receptor-selective ligand (+)-[3H]pentazocine to guinea pig cerebellum was investigated. Di- and trivalent cations biphasically inhibited (+)-[3H]pentazocine binding, revealing multiple affinity states. The rank order of potency of these cations (based on the high affinity component of inhibition) was Zn2+ > Co2+ >> La3+ = Ni2+ = Cd2+ = Mn2+ = Gd2+ > Ba2+ = Sr2+ >> Mg2+ > Ca2+. The inhibition of 1,3-[3H]di(2-tolyl)guanidine binding to the sigma 2 receptor by these cations differed qualitatively and quantitatively from their effects on (+)-[3H]pentazocine binding. Although monovalent cations decreased the Kd for (+)-[3H]pentazocine binding, divalent cations split (+)-[3H]pentazocine binding into low and high affinity components. The Bmax of the high affinity component decreased with increasing divalent cation concentrations. Both mono- and divalent cations significantly reduced the rate of association of (+)-[3H]pentazocine with the sigma 1 receptor without altering the dissociation rate. (+)-[3H]Pentazocine binding was not altered by guanine nucleotides or by treatment with cholera or pertussis toxins. However, nonselective cation channel blockers (cinnarizine, hydroxyzine, prenylamine, amiodarone, and proadifen) potently inhibited (+)-[3H]pentazocine binding. These results indicate that physiologically relevant concentrations of divalent cations allosterically modulate (+)-[3H]pentazocine binding to the sigma 1 receptor, to reveal multiple affinity states. These sites do not represent sigma 1 to sigma 2 subtype interconversion or ternary complex formation with guanine nucleotide-binding proteins. However, the rank order of cation potency and the inhibition of binding by cation channel blockers is consistent with a potential role for sigma receptors as constituents of cation channels.
Mol Pharmacol 1992 Nov
PMID:Modulation of (+)-[3H]pentazocine binding to guinea pig cerebellum by divalent cations. 127 78

We have identified by immunoblotting and ADP-ribosylation by cholera toxin and pertussis toxin the presence of Mr 43 and 46 KDa Gs alpha, and 39 and 41 KDa Gi alpha subunits in rat parotid gland plasma membranes but not in granule membranes. A Mr 28 KDa polypeptide that served as substrate for ADP-ribosylation by both cholera toxin and pertussis toxin was present exclusively in granule membranes. Photoaffinity crosslinking of [alpha-32P]GTP showed the presence of high molecular weight GTP-binding proteins (Mr 160, 100 KDa) in granule membranes. Six low molecular weight GTP-binding proteins (Mr 21-28 KDa) were differentially distributed in both plasma membranes and granule membranes. The present study identifies various GTP-binding proteins in rat parotid gland plasma membranes and granule membranes, and demonstrates the presence of distinct molecular weight GTP-binding proteins in granule membranes. These granule-associated GTP-binding proteins may be involved in secretory processes.
Mol Cell Biochem 1992 Oct 07
PMID:Identification of G-proteins in rat parotid gland plasma membranes and granule membranes: presence of distinct components in granule membranes. 128 Mar 20

The signal transduction pathways of the dopamine-D1 receptor were investigated in two cell types stably transfected with the human D1 receptor cDNA, rat pituitary GH4C1 cells (GH4-hD1), and mouse Ltk-fibroblast cells (L-hD1). In both GH4-hD1 and L-hD1 cell lines, stimulation of the dopamine-D1 receptor induced a marked increase in cAMP accumulation. In addition, dopamine potentiated activation of L-type voltage-dependent calcium channels in a cAMP-dependent manner in GH4-hD1 cells. However, in L-hD1 cells, dopamine increased cytosolic free calcium concentrations ([Ca++]i) by mobilization of intracellular calcium rather than by calcium influx. This effect was correlated with a dopamine-induced enhancement of phospholipase C activity in L-hD1 cells. Pretreatment (24 h) with cholera toxin (CTX) was used to maximally activate the GTP-binding protein (G protein) Gs, causing a maximal elevation of cAMP levels and uncoupling the D1 receptor from Gs. The described actions of dopamine in both cell lines were abolished by pretreatment with CTX, indicating that CTX substrates (e.g. Gs) may mediate these actions. The blockade by CTX was not due to CTX-induced elevation of cAMP, since pretreatment with forskolin or 8-bromo-cAMP to activate cAMP-dependent protein kinase did not inhibit dopamine actions nor alter basal [Ca++]i. Pretreatment (1-3 h) of L-hD1 cells with forskolin (10 microM) or 8-bromo-cAMP (5 mM) altered neither the basal activity of phospholipase C nor basal [Ca++]i in L-hD1 cells but greatly enhanced the dopamine-induced increase of phosphatidyl inositol turnover and [Ca++]i. From these results we conclude that: 1) the dopamine-D1 receptor induces multiple and cell-specific signals, including elevation of cAMP levels in both GH and L cells, cAMP-dependent activation and potentiation of opening of L-type voltage-dependent calcium channel in GH cells, and a novel phosphatidyl inositol-linked mobilization of cellular calcium in L cells; 2) coupling of the D1 receptor to these responses involves CTX-sensitive proteins, possibly Gs; and 3) acute preactivation of cAMP-dependent protein kinase can markedly enhance, rather than attenuate, certain pathways of dopamine-D1 transmembrane signaling.
Mol Endocrinol 1992 Nov
PMID:Cholera toxin-sensitive 3',5'-cyclic adenosine monophosphate and calcium signals of the human dopamine-D1 receptor: selective potentiation by protein kinase A. 128 71


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