scholarly journals Characterization of parathyroid hormone receptors in canine renal cortical plasma membranes using a radioiodinated sulfur-free hormone analogue. Correlation of binding with adenylate cyclase activity.

1979 ◽  
Vol 254 (15) ◽  
pp. 6980-6986 ◽  
Author(s):  
G V Segre ◽  
M Rosenblatt ◽  
B L Reiner ◽  
J E Mahaffey ◽  
J T Potts
Keyword(s):  
Parathyroid Hormone ◽  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Hormone Receptors ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Hormone Analogue

scholarly journals Lysophosphatidylcholines can modulate the activity of the glucagon-stimulated adenylate cyclase from rat liver plasma membranes

1979 ◽  
Vol 178 (1) ◽  
pp. 217-221 ◽  
Author(s):  
M D Houslay ◽  
R W Palmer
Keyword(s):  
Adenylate Cyclase ◽  
Rat Liver ◽  
Plasma Membranes ◽  
Hormone Receptors ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Liver Plasma Membranes ◽  
Rat Liver Plasma Membranes ◽  
Increased Sensitivity

1. Synthetic lysophosphatidylcholines inhibit the glucagon-stimulated adenylate cyclase activity of rat liver plasma membranes at concentrations two to five times lower than those needed to inhibit the fluoride-stimulated activity. 2. Specific 125I-labelled glucagon binding to hormone receptors is inhibited at concentrations similar to those inhibiting the fluoride-stimulated activity. 3. At concentrations of lysophosphatidylcholines immediately below those causing inhibition, an activation of adenylate cyclase activity or hormone binding was observed. 4 These effects are essentially reversible. 5. We conclude that the increased sensitivity of glucagon-stimulated adenylate cyclase to inhibition may be due to the lysophosphatidylcholines interfering with the physical coupling between the hormone receptor and catalytic unit of adenylate cyclase. 6. We suggest that, in vivo, it is possible that lysophosphatidylcholines may modulate the activity of adenylate cyclase only when it is in the hormone-stimulated state.

EFFECT OF GUANYL NUCLEOTIDES ON PARATHYROID HORMONE-RESPONSIVE ADENYLATE CYCLASE IN CHICK KIDNEY

1976 ◽  
Vol 69 (3) ◽  
pp. 401-412 ◽  
Author(s):  
N. H. HUNT ◽  
T. J. MARTIN ◽  
V. P. MICHELANGELI ◽  
J. A. EISMAN
Keyword(s):  
Parathyroid Hormone ◽  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Enzyme Activation ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Amino Terminal ◽  
Nucleotide Analogue ◽  
Amino Terminal Fragment ◽  
Chick Kidney

SUMMARY Both guanosine 5′-triphosphate (GTP) and 5′-guanylylimidodiphosphate (Gpp(NH)p) activated adenylate cyclase (EC 4.6.1.1) in chick kidney plasma membranes. Half-maximal stimulation occurred at 3·1 × 10−6 m for both agents. The maximum increases in adenylate cyclase activity produced by GTP and Gpp(NH)p were respectively 130 and 720% over basal activity. At the end of a 12 min incubation period GTP concentration was 85% of that originally added in the presence of an ATP-regenerating system but less than 20% in its absence. GTP and guanosine 5′-diphosphate inhibited the activation of adenylate cyclase by Gpp(NH)p, suggesting that they all acted at a common site. Gpp(NH)p facilitated the stimulation of adenylate cyclase activity by bovine parathyroid hormone (BPTH) and by the synthetic amino terminal fragment BPTH (1–34), decreasing the concentrations required for half-maximal enzyme activation by a factor of approximately eight in both cases. This property was not shared by the native nucleotide GTP. Gpp(NH)p rendered active (at certain concentrations) a synthetic parathyroid hormone peptide fragment, BPTH (2–34), which was incapable of activating adenylate cyclase in the absence of the nucleotide analogue. This suggested that the GTP analogue, in addition to a direct effect upon adenylate cyclase activity, was capable of influencing hormone interaction with the enzyme complex.

CHICK KIDNEY ADENYLATE CYCLASE: SENSITIVITY TO PARATHYROID HORMONE AND SYNTHETIC HUMAN AND BOVINE PEPTIDES

1974 ◽  
Vol 63 (2) ◽  
pp. 369-375 ◽  
Author(s):  
T. J. MARTIN ◽  
N. VAKAKIS ◽  
J. A. EISMAN ◽  
S. J. LIVESEY ◽  
G. W. TREGEAR
Keyword(s):  
Parathyroid Hormone ◽  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Rat Kidney ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Similar Preparation ◽  
Chick Kidney

SUMMARY Adenylate cyclase activity of crude plasma membranes from chick kidney was stimulated by low doses of parathyroid hormone (PTH). Sensitivity to PTH was ten to twenty times greater than that of a similar preparation from rat kidney cortex. Synthetic peptides consisting of the NH2-terminal 34 amino acids of bovine PTH (BPTH) and of human PTH (HPTH) were assayed, as were several analogues of these peptides. Bovine PTH (1–34) and HPTH (1–34) were equivalent in their action on chick kidney but the human peptide had only 20% of the activity of the bovine peptide on rat kidney cortex adenylate cyclase. Bovine proPTH ( −6→ + 34) and (Tyr1)-BPTH (1–34) had less activity than BPTH (1–34). Bovine PTH (2–34) inhibited the response to BPTH (1–34). Neither salmon calcitonin nor vasopressin stimulated adenylate cyclase activity.

STATES OF ACTIVATION OF CHICK KIDNEY ADENYLATE CYCLASE INDUCED BY PARATHYROID HORMONE AND GUANYL NUCLEOTIDES

1977 ◽  
Vol 72 (1) ◽  
pp. 69-79 ◽  
Author(s):  
V. P. MICHELANGELI ◽  
N. H. HUNT ◽  
T. J. MARTIN
Keyword(s):  
Parathyroid Hormone ◽  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Stable State ◽  
Enzyme Activation ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Incubation Stage ◽  
Subsequent Addition ◽  
Chick Kidney

SUMMARY Several aspects of the activation of adenylate cyclase by guanosine 5′-triphosphate (GTP), 5′-guanylylimidodiphosphate (Gpp(NH)p) and bovine parathyroid hormone (bPTH) have been studied in chick kidney plasma membrane preparations. GTP (10−4 mol/l), Gpp(NH)p (10−4 mol/l) and bPTH (10 i.u./ml) activated adenylate cyclase without any significant time lag. However a 2 min delay was observed before the activity of the enzyme increased after the addition of bPTH (−6 → + 34) to incubations. The early (0–3 min) effects of GTP and Gpp(NH)p upon chick kidney adenylate cyclase activity were antagonized by the addition of the alternative guanyl nucleotide. After 5 min of incubation with kidney plasma membranes, Gpp(NH)p induced a stable state of activation of adenylate cyclase which was not reversible by subsequent addition of GTP. GTP did not induce an irreversible state of enzyme activation. In pre-incubation studies, GTP did not produce a persistent enzyme activation and did not modify the effect of Gpp(NH)p added subsequently at the incubation stage. Gpp(NH)p produced a stable state of activation of adenylate cyclase which was not inhibited by addition of GTP at the incubation stage. Bovine PTH (2–34) inhibited the effect of bPTH upon adenylate cyclase activity when the native hormone (10 i.u./ml) had been incubated with plasma membranes for up to 8 min before addition of the analogue (5 μg/ml). Incubation of plasma membranes with bPTH (2–34) for as little as 10 s prevented activation of adenylate cyclase by subsequent addition of bPTH. This pattern was confirmed in pre-incubation studies. After pre-incubation of kidney membranes with bPTH and bPTH (2–34), followed by washing, an acid extract of the membranes contained immunoreactive bPTH. Gpp(NH)p produced a greater increase in adenylate cyclase activity in membranes pre-incubated with bPTH or bPTH (2–34) than in membranes pre-incubated with buffer alone, suggesting that the hormone and analogue facilitated the interaction of Gpp(NH)p with adenylate cyclase.

Evidence for presence of a new type of neurohypophysial hormone receptor in fish gill epithelium

1990 ◽  
Vol 258 (1) ◽  
pp. R3-R9 ◽  
Author(s):  
M. E. Guibbolini ◽  
B. Lahlou
Keyword(s):  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Hormone Receptors ◽  
Maximal Activity ◽  
Arginine Vasotocin ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Gill Epithelium ◽  
New Type ◽  
V2 Antagonist

Arginine vasotocin (AVT) and isotocin (IT) induced direct inhibition of adenylate cyclase activity in gill plasma membranes of the rainbow trout adapted to freshwater (FW) and seawater (SW). The maximal inhibition was obtained with 10(-11)-10(-10) M (50% inhibitory concentration approximately 10(-13) M), values in agreement with the circulating levels of AVT in trout blood. Specific V1 or V2 agonists or antagonists (with reference to vasopressin) were used to define the specificity of the neurohypophysial peptide receptors involved in this inhibition. The V1 agonist [Phe2,Orn8]vasotocin ([Phe2]OVT) inhibited the basal and glucagon-stimulated adenylate cyclase activity, and this effect in SW (20%) was twice more than in FW (10%). The V2 agonist 1-deamino[Val4,Arg8]-vasopressin (dVDAVP), however, produced a stimulation that was of the same amplitude (10%) in both media. The V1 antagonist [(1-beta-mercapto-beta-beta-cyclopentamethylenepropionic acid), 1-(O-ethyl)Tyr2,Orn8]vasotocin (d(CH2)5[Tyr(Et)2]OVT) totally reversed the AVT- or IT-induced inhibition of basal or glucagon-stimulated cyclase activity, whereas the V1/V2 antagonist [(1-beta-mercapto-beta-beta-cyclopentamethylene propionic acid), 1-(O-ethyl)D-Tyr2,Val4,Arg8]vasopressin (d(CH2)5[D-Tyr(Et)2]-VAVP) (previously used as V2 antagonist in amphibians) had no such effect. When active, all analogues had their maximal activity at 10(-11)-10(-10) M (50% maximal activity approximately 10(-13) M), as observed with the natural peptides. These results, together with our previous observations, point to the gill epithelium as a direct target organ for neurohypophysial peptides and suggest that the hormone receptors involved in fish belong predominantly, if not exclusively, to a new type that we propose to designate as fish neurohypophysial hormone (NHF) receptors while awaiting further characterization.

Selective inhibition by epinephrine of parathyroid hormone-stimulated adenylate cyclase in rat renal cortex

1982 ◽  
Vol 242 (6) ◽  
pp. F721-F726 ◽  
Author(s):  
E. A. Woodcock ◽  
C. I. Johnston
Keyword(s):  
Parathyroid Hormone ◽  
Adenylate Cyclase ◽  
Renal Cortex ◽  
Selective Inhibition ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Renal Tubules ◽  
Direct Inhibition ◽  
Basal Activity ◽  
Absolute Decrease

Parathyroid hormone- (PTH) stimulated adenylate cyclase activity in homogenates of rat renal cortex was inhibited by l-epinephrine. The specificity of the inhibition indicated that it was mediated by alpha 2-receptors. The inhibition of PTH-stimulated activity was greater than the inhibition of basal activity. The absolute decrease in adenylate cyclase activity produced by 10-4 M l-epinephrine was from 16.3 +/-0.6 (SE) to 11.2 +/- 0.6 pmol.min-1.mg-1 for activity stimulated by 10 microgram/ml PTH. Basal activity was decreased from 2.3 +/- 0.07 to 1.7 +/- 0.04. A similar inhibition of PTH-stimulated adenylate cyclase by l-epinephrine was demonstrated in preparations of renal cortical tubules. In contrast, the quantitative decrease in vasopressin-or calcitonin-stimulated activity by 10-4 M l-epinephrine was the same as the decrease in basal activity. These results demonstrate that PTH receptors that stimulated adenylate cyclase and alpha 2-adrenergic receptors that inhibit adenylate cyclase are present on the same cells in the renal tubules. Thus, a mechanism exists whereby alpha-adrenergic agonists can oppose the tubular actions of PTH via a direct inhibition of adenylate cyclase activity.

scholarly journals Elevated membrane cholesterol concentrations inhibit glucagon-stimulated adenylate cyclase

1983 ◽  
Vol 210 (2) ◽  
pp. 437-449 ◽  
Author(s):  
A D Whetton ◽  
L M Gordon ◽  
M D Houslay
Keyword(s):  
Fatty Acid ◽  
Adenylate Cyclase ◽  
Spin Probe ◽  
Plasma Membranes ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Cholesterol Concentration ◽  
Lipid Phase ◽  
Lipid Order ◽  
Liver Plasma Membranes

A method was devised which increases the cholesterol concentration of rat liver plasma membranes by exchange from cholesterol-rich liposomes at low temperature (4 degrees C). When the cholesterol concentration of liver plasma membranes is increased, there is an increase in lipid order as detected by a decrease in mobility of an incorporated fatty acid spin probe. This is accompanied by an inhibition of adenylate cyclase activity. The various ligand-stimulated adenylate cyclase activities exhibit different sensitivities to inhibition by cholesterol, with inhibition of glucagon-stimulated greater than fluoride-stimulated greater than basal activity. The bilayer-fluidizing agent benzyl alcohol is able to reverse the inhibitory effect of cholesterol on adenylate cyclase activity in full. The thermostability of fluoride-stimulated cyclase is increased in the cholesterol-rich membranes. Elevated cholesterol concentrations abolish the lipid-phase separation occurring at 28 degrees C in native membranes as detected by an incorporated fatty acid spin probe. This causes Arrhenius plots of glucagon-stimulated adenylate cyclase activity to become linear, rather than exhibiting a break at 28 degrees C. It is suggested that the cholesterol contents of both halves of the bilayer are increased by the method used and that inhibition of adenylate cyclase ensues, owing to the increase in lipid order and promotion of protein-protein and specific cholesterol-phospholipid interactions.

scholarly journals The activity of glucagon-stimulated adenylate cyclase from rat liver plasma membranes is modulated by the fluidity of its lipid environment

1978 ◽  
Vol 174 (1) ◽  
pp. 179-190 ◽  
Author(s):  
I Dipple ◽  
M D Houslay
Keyword(s):  
Adenylate Cyclase ◽  
Benzyl Alcohol ◽  
Plasma Membranes ◽  
Break Point ◽  
Alcohol Concentration ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Lipid Phase ◽  
Glucagon Receptor ◽  
Arrhenius Plots

1. The local anaesthetic benzyl alcohol progressively activated glucagon-stimulated adenylate cyclase activity up to a maximum at 50 mM-benzyl alcohol. Further increases in benzyl alcohol concentration inhibited the activity. The fluoride-stimulated adenylate cyclase activity was similarly affected except for an inhibition of activity occurring at low benzyl alcohol concentrations (approx. 10 mM. 2. The fluoride-stimulated adenylate cyclase activity of a solubilized enzyme preparation was unaffected by any of the benzyl alcohol concentrations tested. 3. Increases in 3-phenylpropan-1-ol and 5-phenylpentan-1-ol concentrations progressively activated both the fluoride- and glucagon-stimulated adenylate cyclase activities up to a maximum, above which further increases in alcohol concentration inhibited the activities. 4. The ‘break’ points in Arrhenius plots of glucagon-stimulated adenylate cyclase activity in native plasma membranes, and in plasma membranes fused with synthetic dimyristoyl phosphatidylcholine so as to constitute 60% of the total lipid pool, were decreased by approx. 6 degrees C by addition of 40 mM-benzyl alcohol. This was accompanied by a fall in the associated activation energies. 6. Arrhenius plots of fluoride-stimulated adenylate cyclase activity in the presence and absence of 40 mM-benzyl alcohol were linear, although addition of benzyl alcohol caused a dramatic decrease in the associated activation energy of the reaction. 7. 5′-Nucleotidase activity was stimulated by benzyl alcohol, and the ‘break’ point in the Arrhenius plot of its activity was decreased by about 6 degrees C by addition of 40 mM-benzyl alcohol to the assay. 8. It is suggested that benzyl alcohol effects a fluidization of the bilayer, which is clearly demonstrated by its ability to lower the temperature of a lipid phase separation occurring at 28 degrees C in the outer half of the bilayer to around 22 degrees C. The increase in bilayer fluidity relieves a physical constraint on the membrane-bound adenylate cyclase, activating the enzyme. 9. The various inhibition phenomena are discussed in detail, together with the suggestion that the interaction between the uncoupled catalytic unit of adenylate cyclase and the lipids of the bilayer is altered on its physical coupling to the glucagon receptor.

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