scholarly journals Relation of Glucagon-specific Binding Sites to Glucagon-dependent Stimulation of Adenylyl Cyclase Activity in Plasma Membranes of Rat Liver

1973 ◽  
Vol 248 (6) ◽  
pp. 2056-2061
Author(s):  
Lutz Birnbaumer ◽  
Stephen L. Pohl
Keyword(s):  
Adenylyl Cyclase ◽  
Rat Liver ◽  
Binding Sites ◽  
Plasma Membranes ◽  
Specific Binding ◽  
Cyclase Activity ◽  
Adenylyl Cyclase Activity ◽  
Specific Binding Sites ◽  
Stimulation Of

Prostaglandin E2 receptors in the heart are coupled to inhibition of adenylyl cyclase via a pertussis toxin sensitive G protein

1992 ◽  
Vol 70 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Richard W. Lerner ◽  
Gary D. Lopaschuk ◽  
Peter M. Olley
Keyword(s):  
Adenylyl Cyclase ◽  
G Protein ◽  
Pertussis Toxin ◽  
Binding Sites ◽  
Cyclase Activity ◽  
Prostaglandin E ◽  
Adenylyl Cyclase Activity ◽  
Adp Ribosylation ◽  
Number Of Binding Sites ◽  
Guanine Nucleotide Binding

In previous studies we have identified and isolated a prostaglandin E2 (PGE2) receptor from cardiac sarcolemmal (SL) membranes. Binding of PGE2 to this receptor in permeabilized SL vesicles inhibits adenylyl cyclase activity. The purpose of this study was to determine if the cardiac PGE2 receptor is coupled to adenylyl cyclase via a pertussis toxin sensitive guanine nucleotide binding inhibitory (Gi) protein. Incubation of permeabilized SL vesicles in the presence of 100 μM 5′-guanylamidiophosphate, Gpp(NH)p, a nonhydrolyzable analogue of GTP, resulted in a shift in [3H]PGE2 binding from two sites, one of high affinity (KD = 0.018 ± 0.003 nM) comprising 7.7% of the total available binding sites and one of lower affinity (KD = 1.9 ± 0.7 nM) to one site of intermediate affinity (KD = 0.52 ± 0.01 nM) without a significant change in the total number of PGE2 binding sites. A shift from two binding sites to one binding site in the presence of Gpp(NH)p was also observed for [3H]dihydroalprenolol binding to permeabilized cardiac SL. When permeabilized SL vesicles were pretreated with activated pertussis toxin, ADP-ribosylation of a 40- to 41-kDa protein corresponding to Gi was observed. ADP-ribosylation of SL resulted in a shift in [3H]PGE2 binding to one site of intermediate affinity without significantly changing the number of binding sites. In alamethicin permeabilized SL vesicles, 1 nM PGE2 significantly decreased (30%) adenylyl cyclase activity. Pretreatment with activated pertussis toxin overcame the inhibitory effects of PGE2. These results demonstrate that the cardiac PGE2 receptor is coupled to adenylyl cyclase via a pertussis toxin sensitive Gi protein. They also demonstrate that the interaction of this Gi protein with the PGE2 receptor is important in the regulation of PGE2 binding to its receptor.Key words: prostaglandin E2, sarcolemma, heart, adenylyl cyclase, G protein.

Regulation of angiotensin II binding sites in neuronal cultures by catecholamines

1989 ◽  
Vol 257 (4) ◽  
pp. C706-C713 ◽  
Author(s):  
L. M. Myers ◽  
C. Sumners
Keyword(s):  
Angiotensin Ii ◽  
Binding Sites ◽  
Phorbol Esters ◽  
De Novo ◽  
Specific Binding ◽  
Physiological Mechanism ◽  
Neuronal Cultures ◽  
Ang Ii ◽  
Specific Binding Sites ◽  
Stimulation Of

Previous studies determined that direct activation of protein kinase C (PKC) with phorbol esters increases the number of angiotensin II (ANG II)-specific binding sites in neuronal cultures prepared from the hypothalamus and brain stem of 1-day-old rats. In the physiological situation, PKC is activated by diacylglycerol, which can be produced by multiple pathways, such as stimulation of inositol phospholipid (IP) hydrolysis, phosphatidylcholine hydrolysis, or by de novo synthesis. In the present study we have examined whether stimulation of IP hydrolysis, and presumably activation of PKC, can mimic the actions of phorbol esters on ANG II-specific binding. We have incubated neuronal cultures with agents that increase IP hydrolysis and have determined the effects on ANG II-specific binding. Incubation of neuronal cultures with norepinephrine (NE) at concentrations (greater than 5 microM) and for times (15-60 min) that cause large increases in IP hydrolysis caused increases in the number of ANG II-specific binding sites, mimicking the actions of phorbol esters. The return of IP hydrolysis to control values was associated with a return of ANG II-specific binding to control levels. The upregulatory action of NE was abolished by prazosin, demonstrating the involvement of alpha 1-adrenergic receptors. In addition, this effect was blunted by the PKC antagonist H 7, suggesting PKC involvement in the response. Thus we have determined a potential physiological mechanism by which stimulation of IP hydrolysis by NE, and possible subsequent activation of PKC, leads to upregulation of ANG II-specific binding sites in neuronal cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of heavy metals and lanthanum on sugar transport in isolated guinea pig left atria

1980 ◽  
Vol 58 (10) ◽  
pp. 1184-1188 ◽  
Author(s):  
I. Bihler ◽  
L. E. Hoeschen ◽  
P. C. Sawh
Keyword(s):  
Heavy Metals ◽  
Guinea Pig ◽  
Binding Sites ◽  
Specific Binding ◽  
Sugar Transport ◽  
Free Medium ◽  
Specific Binding Sites ◽  
Stimulation Of

The effect of heavy metals on sugar transport in fully resting guinea pig left atria was studied by measuring the tissue–medium distribution of 3-methylglucose. Basal sugar transport was increased significantly by all heavy metals tested (Co2+, Ni2+, Zn2+, Mn2+ (2 mM)) and by La3+ (0.05 mM) but 1 mM La3+ had no effect. The stimulation of sugar transport by insulin, hyperosmolarity, K+-free medium, or 10−5 M ouabain was strongly antagonized by Ni2+, Zn2+, and La3+ but was unaffected by Co2+ and Mn2+. The heavy metals did not affect intracellular Na2+ and K+, whether in the basal state or when the Na+ pump was depressed by ouabain or K+-free medium. The data suggest that Ca2+ antagonistic ions may affect sugar transport both by inhibiting Ca2+ influx and by competing with Ca2+ for specific binding sites presumably involved in the regulation of sugar transport.

scholarly journals 5-CT stimulation of adenylyl cyclase activity in guinea-pig hippocampus: evidence for involvement of 5-HT7 and 5-HT1A receptors

1999 ◽  
Vol 128 (1) ◽  
pp. 158-164 ◽  
Author(s):  
David R Thomas ◽  
Derek N Middlemiss ◽  
Stephen G Taylor ◽  
Paul Nelson ◽  
Anthony M Brown
Keyword(s):  
Guinea Pig ◽  
Adenylyl Cyclase ◽  
Cyclase Activity ◽  
Adenylyl Cyclase Activity ◽  
Stimulation Of

Binding sites for islet amyloid polypeptide in mammalian lung: species variation and effects on adenylyl cyclase

1995 ◽  
Vol 73 (7) ◽  
pp. 1030-1036 ◽  
Author(s):  
Ranjev Bhogal ◽  
David M. Smith ◽  
Ali A. Owji ◽  
Stephen R. Bloom
Keyword(s):  
Guinea Pig ◽  
Adenylyl Cyclase ◽  
Binding Sites ◽  
Islet Amyloid Polypeptide ◽  
Calcitonin Gene Related Peptide ◽  
Cyclase Activity ◽  
Adenylyl Cyclase Activity ◽  
Islet Amyloid ◽  
Related Peptide ◽  
Calcitonin Gene

Islet amyloid polypeptide (IAPP) and calcitonin gene related peptide (CGRP) share a 47% sequence homology. IAPP can interact with adenylyl cyclase coupled CGRP receptors. We have examined [125I]IAPP binding in mouse, pig, and guinea pig lung membranes in competition with IAPP, CGRP, and CGRP(8–37). Three types of site were shown by order of potency: (i) mouse, IAPP > CGRP(8–37) [Formula: see text] CGRP; (ii) pig, CGRP > IAPP > CGRP(8–37); and (iii) guinea pig, CGRP = IAPP = CGRP(8–37). Chemical cross-linking of [125I]IAPP and [125I]CGRP binding sites in lung demonstrated that both sites had similar molecular weights in any one species but differed across species, i.e., mouse Mr = 70 000 and 98 000; pig Mr = 68 000, 56 000, and 47 000; and guinea pig Mr = 106 000 and 56 000. Adenylyl cyclase activity was stimulated by forskolin and AlCl3–NaF in rat, mouse, pig, and guinea pig membranes. Only in mouse and pig were CGRP and IAPP able to stimulate adenylyl cyclase activity. In mouse lung CGRP and IAPP stimulated adenylyl cyclase activity with EC50 values of 642 ± 222 nM (n = 4) and 325 ± 115 nM (n = 4), respectively. In pig lung membranes EC50 values were 5.7 ± 0.3 nM (n = 4) for CGRP and 1230 ± 1130 nM (n = 4) for IAPP. Thus IAPP either did not stimulate adenylyl cyclase activity in these lung membranes or did so with a low potency.Key words: islet amyloid polypeptide, amylin, calcitonin gene related peptide, lung, receptors.

ChemInform Abstract: Polychlorinated Biphenyls and Related Compound Interactions with Specific Binding Sites for Thyroxine in Rat Liver Nuclear Extracts.

ChemInform ◽  
1987 ◽  
Vol 18 (23) ◽  
Author(s):  
J. MCKINNEY ◽  
R. FANNIN ◽  
S. JORDAN ◽  
K. CHAE ◽  
U. RICKENBACHER ◽  
...  
Keyword(s):  
Polychlorinated Biphenyls ◽  
Rat Liver ◽  
Related Compound ◽  
Binding Sites ◽  
Specific Binding ◽  
Specific Binding Sites ◽  
Nuclear Extracts
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