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.

EVIDENCE FOR A SEPARATE ADENYLATE CYCLASE SYSTEM RESPONSIVE TO BETA-ADRENERGIC STIMULATION IN THE RENAL CORTEX OF THE RAT

1974 ◽  
Vol 77 (3) ◽  
pp. 604-611 ◽  
Author(s):  
Norman H. Bell ◽  
John Fleming ◽  
Joanne Benedict ◽  
Lisa Pantzer
Keyword(s):  
Parathyroid Hormone ◽  
Adenylate Cyclase ◽  
Renal Cortex ◽  
Blocking Agent ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Adenylate Cyclase System ◽  
Adrenergic Stimulation ◽  
Beta Adrenergic ◽  
Increased Activity

ABSTRACT Previous studies in other laboratories had indicated that some of the effects of parathyroid hormone on skeletal tissue and the renal tubule to influence ion metabolism can be produced by beta-adrenergic stimulation. Studies were carried out to determine whether the same adenylate cyclase system in rat renal cortex is activated by parathyroid hormone and isoproterenol. At maximal effective concentration of dose response, parathyroid hormone (2 × −5 m) increased adenylate cyclase activity by some 415 per cent, isoproterenol (10−6 m) increased activity by some 40 to 50 per cent, vasopressin (10−5 m) increased activity by some 96 per cent and porcine calcitonin (10−5 m) increased activity by some 92 per cent. Dl-propranolol (10−5 m), a beta-adrenergic receptor blocking agent, prevented the increase in enzyme activity produced by isoproterenol (10−6 m), did not diminish the increase in activity produced by parathyroid hormone (10−6 m) and did not influence basal adenylate cyclase activity by itself. The combined maximal concentrations of isoproterenol together with either parathyroid hormone, vasopressin or porcine calcitonin were additive. These results indicate that there is an adenylate cyclase system in rat renal cortex which can be activated by beta-adrenergic stimulation with isoproterenol, and is separate from the systems responsive to parathyroid hormone, vasopressin or calcitonin.

Effects of arginine vasopressin on the thin ascending limb of Henle's loop of hamsters

1982 ◽  
Vol 243 (2) ◽  
pp. F167-F172 ◽  
Author(s):  
M. Imai ◽  
E. Kusano
Keyword(s):  
Adenylate Cyclase ◽  
Arginine Vasopressin ◽  
Chloride Transport ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Renal Tubules ◽  
Thick Ascending Limb ◽  
Cl Transport ◽  
Henle's Loop ◽  
Perfusion Studies

Arginine vasopressin (AVP) has been shown to stimulate active Cl transport across the medullary thick ascending limb of Henle's loop (MAL) in association with an increase in adenylate cyclase activity. To determine whether the failure to demonstrate active Cl transport across the thin ascending limb of Henle's loop (TAL) in previous in vitro perfusion studies was due to the absence of AVP in the preparation, we examined the effect of AVP on adenylate cyclase activity and Cl transport in the hamsters TAL. AVP (1 mU/ml) increased adenylate cyclase activity in the hamster TAL (20.7 +/- 5.2 control vs. 46.2 +/- 10.1 fmol . mm-1 . 30 min-1, n = 6, P less than 0.05) but not in the descending limb (27.8 +/- 7.0 control vs. 20.4 +/- 2.7, n = 4, P less than 0.05). When both MAL and TAL were perfused, a lumen-positive transepithelial voltage (Vt) was observed. The Vt was increased by adding 1 or 10 mU/ml AVP to the bath. When only the TAL was perfused, the Vt was not different from zero. Similar results were obtained in mouse renal tubules. In other experiments, AVP did not affect the diffusion potential generated when a transepithelial NaCl gradient was present. AVP or dibutyryl cAMP caused little or no change in efflux of radioactive chloride across the hamster TAL. These findings suggest that electrogenic chloride transport is not demonstrable in the TAL even in the presence of AVP. The physiologic role of AVP-sensitive adenylate cyclase in the TAL remains to be established.

The effect of L-glutamate and related agents on adenylate cyclase in the cestode Hymenolepis diminuta

1991 ◽  
Vol 69 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Harley Eklove ◽  
Rodney A. Webb
Keyword(s):  
Amino Acid ◽  
Adenylate Cyclase ◽  
Hymenolepis Diminuta ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Tissue Slices ◽  
Basal Activity ◽  
Glutamate Agonists ◽  
Acidic Compounds ◽  
Type Receptor

The effect of the putative amino acid transmitter, L-glutamate, on adenylate cyclase in crude membrane preparations of the rat tapeworm Hymenolepis diminuta was investigated to determine if glutamate effects the generation of the second messenger cAMP. Addition of glutamate at 10−3 and 5.5 × 10−9 M resulted in significant elevations in basal activity of adenylate cyclase, while concentrations in the 10−5–10−7 M range caused significant depressions below basal activity. Assays with glutamate agonists and other acidic compounds showed glutamate to be the only amino acid, dicarboxylic acid, or acidic compound capable of this pattern of stimulation and inhibition. While the response of adenylate cyclase to glutamate agonists suggested that an N-methyl-D-aspartic acid (NMDA) type receptor may be present, glutamate agents acting as NMDA antagonists in vertebrate systems were agonists. Metabolic end products of glycolysis stimulated adenylate cyclase, suggesting that these, along with metabolic glutamate may regulate glycolytic enzymes. Only 10−3 M L-glutamate significantly stimulated adenylate cyclase activity in tissue slices, and this response was restricted to those slices rich in nervous tissues. L-Glutamate eliminated the 5-hydroxytryptamine (5-HT) stimulated adenylate cyclase response suggesting that glutamate can modulate the 5-HT stimulated elevations in adenylate cyclase activity. The data support the hypothesis that L-glutamate is a neurotransmitter–modulator in the cestode.Key words: L-glutamate, cAMP, cestode, modulator.

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.

scholarly journals Calcitonin-sensitive adenylate cyclase in rat renal tubular membranes

1975 ◽  
Vol 150 (3) ◽  
pp. 305-314 ◽  
Author(s):  
N Loreau ◽  
C Lepreux ◽  
R Ardaillou
Keyword(s):  
Parathyroid Hormone ◽  
Adenylate Cyclase ◽  
Salmon Calcitonin ◽  
Maximum Velocity ◽  
Membrane Receptors ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Human Calcitonin ◽  
Renal Tubular ◽  
Tubular Membranes

1. Renal tubular membranes from rat kidneys were prepared, and adenylate cyclase activity was measured under basal conditions, after stimulation by NaF or salmon calcitonin. Apparent Km value of the enzyme for hormone-linked receptor was close to 1 × 10(-8) M. 2. The system was sensitive to temperature and pH. pH was found to act both on affinity for salmon calcitonin-linked receptor and maximum stimulation, suggesting an effect of pH on hormone-receptor binding and on a subsequent step. 3. KCl was without effect areas whereas CoCl and CaCl2 above 100 muM and MnCl2 above 1 muM inhibited F--and salmon calcitonin-sensitive adenylate cyclase activities. The Ca2+ inhibition of the response reflected a fall in maximum stimulation and not a loss of affinity of salmon calcitonin-linked receptor for the enzyme. 4. The measurement of salmon calcitonin-sensitive adenylate cyclase activity as a function of ATP concentration showed that the hormone increases the maximum velocity of the adenylate cyclase. GTP, ITP and XTP at 200 muM did not modify basal, salmon calcitonin- and parathyroid hormone-sensitive adenylate cyclase activities. 5. Basal, salmon calcitonin- and F--sensitive adenylate cyclase activities decreased at Mg2+ concentrations below 10 mM. High concentrations of Mg2+ (100 mM) led to an inhibition of the F--stimulated enzyme. 6. Salmon calcitonin-linked receptor had a greater affinity for adenylate cyclase than human or porcine calcitonin-linked receptors. There was no additive effect of these three calcitonin peptides whereas parathyroid hormone added to salmon calcitonin increased adenylate cyclase activity, thus showing that both hormones bound to different membrane receptors. Human calcitonin fragments had no effect on adenylate cyclase activity. 7. Salmon calcitonin-stimulated adenylate cyclase activity decreased with the preincubation time. This was due to progressive degradation of the hormone and not to the rate of binding to membrane receptors.

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