Gluco- and mineralocorticoids control adenylate cyclase in specific nephron segments

Adrenal insufficiency is associated with an impairment of kidney diluting and concentrating ability, defects that may result from alterations of vasopressin-induced adenosine 3',5'-cyclic monophosphate (cAMP) production. The purpose of this study were 1) to localize the sites of decreased vasopressin-stimulated adenylate cyclase (AC) activity along the nephron of adrenalectomized rats; 2) to determine whether the response of AC to other hormones is altered by adrenalectomy; 3) to evaluate whether changes in AC are due to the deficiency in mineralocorticoids and/or glucocorticoids; and 4) to characterize the mechanism of action of corticosteroids on the AC system. Results indicate that adrenalectomy reduced AC stimulation by vasopressin, glucagon, and calcitonin in the thick ascending limb, whereas only the response to vasopressin decreased in the collecting tubule. Glucocorticoid administration curtailed adrenalectomy-induced alterations of AC in the thick ascending limb, whereas that in the collecting tubule was prevented by mineralocorticoids. Adrenalectomy did not alter forskolin-stimulated AC, whereas it decreased responses to aluminum fluoride and cholera toxin. Finally, alterations of fluoride- and cholera toxin-stimulated AC were prevented by glucocorticoid and mineralocorticoid repletion in the thick ascending limb and collecting tubule, respectively.

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Ontogenesis of hormone-dependent adenylate cyclase in isolated rat nephron segments

AJP Renal Physiology ◽

10.1152/ajprenal.1984.247.2.f316 ◽

1984 ◽

Vol 247 (2) ◽

pp. F316-F325 ◽

Cited By ~ 3

Author(s):

M. Imbert-Teboul ◽

D. Chabardes ◽

A. Clique ◽

M. Montegut ◽

F. Morel

Keyword(s):

Parathyroid Hormone ◽

Adenylate Cyclase ◽

Rat Kidney ◽

Basolateral Membrane ◽

Thick Ascending Limb ◽

Membrane Area ◽

Nephron Segments ◽

Target Sites ◽

Collecting Tubule ◽

Kinetics Of

Ontogenesis of hormone-dependent adenylate cyclase (AC) was investigated in rat kidney by single tubule microassay between two days postnatal and adulthood. This approach allowed us to analyze the kinetics of vasopressin-sensitive AC maturation in its tubular target sites, namely the thick ascending limb and collecting tubule. It was also possible to compare in a single segment--the thick ascending limb--the kinetics of AC ontogenesis for three hormones-- vasopressin, calcitonin, and parathyroid hormone. The results show that 1) 2 days after birth AC is still poorly responsive to vasopressin, especially in the thick ascending limb. By contrast, this segment exhibits marked AC responses to calcitonin and parathyroid hormone. 2) For a given hormone, the kinetics of AC ontogenesis depends on the segment in which the receptor-enzyme complex is located. 3) For a given segment, the pattern of AC maturation is specific for each hormone. These data indicate that the process of tubular AC maturation cannot be accounted for simply by an increase in basolateral membrane area or by the synthesis of new catalytic units. More specific mechanisms must be involved that regulate independently the synthesis of each kind of hormone receptor and/or its coupling to cyclase.

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Difference in the Na affinity of Na(+)-K(+)-ATPase along the rabbit nephron: modulation by K

AJP Renal Physiology ◽

10.1152/ajprenal.1990.259.2.f246 ◽

1990 ◽

Vol 259 (2) ◽

pp. F246-F250 ◽

Cited By ~ 11

Author(s):

C. Barlet-Bas ◽

L. Cheval ◽

C. Khadouri ◽

S. Marsy ◽

A. Doucet

Keyword(s):

Atpase Activity ◽

Thick Ascending Limb ◽

Kidney Cells ◽

Nephron Segments ◽

Adaptive Property ◽

Collecting Tubule ◽

Pump Activity ◽

K Concentration ◽

Cortical Collecting Tubule

The sensitivity of Na(+)-K(+)-ATPase to Na was determined in single segments of rabbit nephron isolated by microdissection. In the cortical collecting tubule (CCT), Na(+)-K(+)-ATPase was threefold more sensitive to Na (apparent K0.5 approximately 3 mM) than in proximal convoluted tubule and cortical thick ascending limb (apparent K0.5 approximately 10 mM). Furthermore, increasing K concentration from 5 to greater than 100 mM markedly reduced the affinity of the pump for Na in all three nephron segments. In fact, the main shift in Na affinity occurred when K changed from 100 to 120 mM; in the CCT, increasing K concentration from 100 to 120 mM while maintaining Na concentration at 10 mM reduced Na(+)-K(+)-ATPase activity by greater than 35%. These findings confirm that, in kidney cells as in other cells, intracellular Na limits the rate of Na(+)-K(+)-ATPase. Thus any alteration of intracellular Na concentration modifies the pump activity in a way that contributes to the restoration of intracellular Na homeostasis. This adaptive property is particularly efficient in the collecting tubule in which the apparent K0.5 of the pump for Na is close to normal intracellular Na concentration. Furthermore, changes in intracellular K concentration, which usually accompany those of Na so as to maintain the total cation concentration constant, potentiate the regulatory role of Na through modifications of its affinity for the pump.

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Ontogeny of hepatic insulin and glucagon receptors and adenylate cyclase in rabbit

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1983.244.6.e624 ◽

1983 ◽

Vol 244 (6) ◽

pp. E624-E631

Author(s):

S. Ganguli ◽

M. K. Sinha ◽

B. Sterman ◽

P. Harris ◽

M. A. Sperling

Keyword(s):

Adenylate Cyclase ◽

Cholera Toxin ◽

Plasma Membranes ◽

Specific Binding ◽

Regulatory Protein ◽

Late Gestation ◽

Camp Production ◽

Hormonal Activation ◽

Glucagon Receptors ◽

Significant Increment

In rabbit liver plasma membranes (LPM), specific binding of 125I-insulin rapidly increased in late gestation and peaked at birth, declining thereafter. In contrast, 125I-glucagon binding was lowest in late gestation, somewhat higher at birth, and increased by 48 h although only to 20-25% of adult. These changes in binding were due to changing numbers of receptors involving predominantly high affinity sites for insulin and low affinity sites for glucagon, with only minor changes in affinity. Despite measurable glucagon receptors by birth, fetal LPM produced no increment above basal in cAMP production with maximal doses of glucagon (10(-6) M), prostaglandin E1 (10(-4) M), or epinephrine (10(-4) M). Near birth only NaF (10 mM) produced a modest but significant increment in cAMP. By 2 h postbirth, all stimuli evoked significant increments in cAMP production that increased progressively but was still only 15-20% of adult at 48 h. Furthermore, although specific binding of cholera toxin was greater in fetal LPM (11 +/- 1 vs. 6 +/- 1%), cholera toxin-stimulated cAMP production increased by only 12-26% above basal in the fetus compared with 220% in adult. Markers of membrane purity including 5'-nucleotidase, phosphodiesterase, and insulin or glucagon degradation were not different in fetus and adult. We conclude that receptors and components of the adenylate cyclase complex mature independently; initial coupling occurs between the G/F regulatory protein and the catalytic unit (NaF but not hormonal activation) followed within hours of birth by coupling to the hormone receptor.

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Tannin inhibits adenylate cyclase in airway epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1995.268.5.l851 ◽

1995 ◽

Vol 268 (5) ◽

pp. L851-L855

Author(s):

M. M. Cloutier ◽

L. Guernsey

Keyword(s):

Epithelial Cells ◽

Adenylate Cyclase ◽

Cholera Toxin ◽

Airway Epithelial Cells ◽

Cyclase Activity ◽

Adenylate Cyclase Activity ◽

Airway Epithelial ◽

Camp Production ◽

Dose Dependent ◽

In Cells

Tannin, isolated from cotton bracts extract and implicated in the pathogenesis of byssinosis, inhibits adenosine 3',5'-cyclic monophosphate (cAMP) production and Cl- secretion in bovine airway epithelial cells in part by inhibiting adrenergic receptor binding. The purpose of this study was to determine whether tannin affected other parts of the adrenergic-cAMP signal transduction pathway by examining the effect of tannin on guanosine 5'-triphosphate (GTP)-regulatory pathways (G proteins) and on adenylate cyclase activity. cAMP production in confluent airway epithelial cells was measured in the presence of cholera toxin (100 micrograms/ml), an activator of GS proteins, and forskolin (0.1-1,000 microM), a direct activator of adenylate cyclase. Cholera toxin stimulated cAMP production; this response, however, was inhibited in cells pretreated with 50 micrograms/ml tannin. Forskolin (100 microM) stimulated cAMP production 13-fold above baseline values. Tannin pretreatment inhibited the stimulatory effect of forskolin on cAMP release in a dose-dependent manner with a tannin concentration causing 50% inhibition of 7.5 micrograms/ml. The stimulatory effect of forskolin on cAMP release was completely inhibited in cells pretreated with 50 micrograms/ml tannin. The inhibition was reversible 3 h after removal of tannin from the solution. Tannin also inhibited forskolin-stimulated adenylate cyclase activity in a dose-dependent, noncompetitive manner. We conclude that forskolin and cholera toxin stimulate cAMP production in airway epithelial cells and that tannin inhibits the production of cAMP in airway epithelial cells by a direct effect on adenylate cyclase activity.

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Defined human renal tubular epithelia in culture: growth, characterization, and hormonal response

AJP Renal Physiology ◽

10.1152/ajprenal.1985.248.3.f436 ◽

1985 ◽

Vol 248 (3) ◽

pp. F436-F443 ◽

Cited By ~ 2

Author(s):

P. D. Wilson ◽

M. A. Dillingham ◽

R. Breckon ◽

R. J. Anderson

Keyword(s):

Primary Cultures ◽

Thick Ascending Limb ◽

Marker Enzyme ◽

Nephron Segments ◽

Growth Characterization ◽

Proximal Straight Tubule ◽

Collecting Tubule ◽

Culture Growth ◽

Renal Tubular

Individually microdissected nephron segments of defined epithelial origin from human kidneys were cultured in vitro in the present studies. Nephron segments of proximal convoluted tubule, proximal straight tubule, cortical thick ascending limb of Henle, and cortical collecting tubule were grown in defined media. Each cell type retained differentiated characteristics as assessed by ultrastructural morphology, marker enzyme profiles, and adenylate cyclase response to selected hormones. These studies demonstrate the feasibility of using primary cultures of well-defined segments of the human nephron to study human renal tubular epithelia in vitro.

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Effect of metabolic acidosis and alkalosis on NEM-sensitive ATPase in rat nephron segments

AJP Renal Physiology ◽

10.1152/ajprenal.1992.262.4.f583 ◽

1992 ◽

Vol 262 (4) ◽

pp. F583-F590 ◽

Cited By ~ 5

Author(s):

C. Khadouri ◽

S. Marsy ◽

C. Barlet-Bas ◽

L. Cheval ◽

A. Doucet

Keyword(s):

Metabolic Acidosis ◽

Atpase Activity ◽

Thick Ascending Limb ◽

Nephron Segments ◽

Medullary Thick Ascending Limb ◽

Henle's Loop ◽

Collecting Tubule ◽

Nephron Segment ◽

Electrogenic Proton Pump ◽

Chloride Treatment

An N-ethylmaleimide (NEM)-sensitive adenosinetriphosphatase (ATPase) displaying the kinetic and pharmacological properties of an electrogenic proton pump has been described in the different segments of rat nephron, where it mediates part of the active tubular proton secretion. This study was therefore designed to evaluate whether changes in urinary acidification observed during metabolic acidosis or alkalosis were associated with alterations of the activity of tubular NEM-sensitive ATPase, and if so, to localize the nephron segments responsible for these changes. Within 1 wk after the onset of ammonium chloride treatment, rats developed a metabolic acidosis, and NEM-sensitive ATPase activity was markedly increased in the medullary thick ascending limb of Henle's loop and outer medullary collecting tubule, and slightly increased in the cortical collecting tubule. Conversely, treatment with sodium bicarbonate induced a metabolic alkalosis that was accompanied by decreased NEM-sensitive ATPase activity in medullary thick ascending limb and outer medullary collecting tubule. NEM-sensitive ATPase activity was not altered in any other nephron segment tested in alkalotic and acidotic rats, i.e., the proximal tubule and the cortical thick ascending limb of Henle's loop. Changes qualitatively similar were observed as soon as 3 h after the onset of NaHCO3 or NH4Cl-loading. In the medullary collecting tubule, alterations of NEM-sensitive ATPase activity are in part due to hyperaldosteronism observed in both acidotic and alkalotic rats.(ABSTRACT TRUNCATED AT 250 WORDS)

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Changes in tubular basolateral membrane markers after chronic DOCA treatment

AJP Renal Physiology ◽

10.1152/ajprenal.1983.245.1.f100 ◽

1983 ◽

Vol 245 (1) ◽

pp. F100-F109 ◽

Cited By ~ 3

Author(s):

G. El Mernissi ◽

D. Chabardes ◽

A. Doucet ◽

A. Hus-Citharel ◽

M. Imbert-Teboul ◽

...

Keyword(s):

Adenylate Cyclase ◽

Atpase Activity ◽

Protein Content ◽

Basolateral Membrane ◽

Chronic Administration ◽

Distal Nephron ◽

Nephron Segments ◽

Collecting Tubule ◽

Nephron Segment ◽

Cortical Collecting Tubule

Chronic administration of DOCA to rabbits is known to increase the surface area of the basolateral membrane and the Na-K-ATPase activity of the cortical collecting tubule (CCT). We attempted to ascertain 1) whether Na-K-ATPase is the only basolateral membrane marker induced by DOCA, and 2) whether CCT is the only nephron segment affected by this steroid. We measured the activity of Na-K-ATPase and adenylate cyclase (AC) and the protein content of nephron segments microdissected from control and DOCA-treated rabbits. Morphogenic effects of DOCA, assessed by 30-60% increases in protein content, were specifically observed in the distal convoluted tubule, CCT, and medullary collecting tubule. When expressed as a function of tubular length, Na-K-ATPase activity rose from 80 to 200% in all these segments, whereas the increments in AC of 40-70%, observed in response to four different hormones, occurred only in some of them. When expressed as a function of protein content, Na-K-ATPase activity increased but AC activity remained unchanged. This study indicates that the morphogenic action resulting from chronic DOCA administration affects the entire rabbit distal nephron. During this action Na-K-ATPase is the preferentially induced enzyme.

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Effect of adrenalectomy on NEM-sensitive ATPase along rat nephron and on urinary acidification

AJP Renal Physiology ◽

10.1152/ajprenal.1987.253.3.f495 ◽

1987 ◽

Vol 253 (3) ◽

pp. F495-F499 ◽

Cited By ~ 1

Author(s):

C. Khadouri ◽

S. Marsy ◽

C. Barlet-Bas ◽

A. Doucet

Keyword(s):

Atpase Activity ◽

Automatic Determination ◽

Outer Medulla ◽

Proton Secretion ◽

Nephron Segments ◽

Collecting Tubule ◽

Single Nephron ◽

Electrogenic Proton Pump ◽

Adrenalectomized Rats

An N-ethyl-maleimide (NEM)-sensitive ATPase that displays the properties of an electrogenic proton pump has been described in the different segments of the rat nephron where it mediates part of the active tubular proton secretion. Because corticosteroids are known to control kidney acidification, we evaluated whether or not NEM-sensitive ATPase is a target of corticosteroids in some nephron segments. For this purpose we measured NEM-sensitive ATPase activity in the different segments of nephron microdissected from normal and adrenalectomized rats. Results indicate that within 1 wk after adrenalectomy NEM-sensitive ATPase activity was markedly decreased in both cortical and outer medullary portions of the collecting tubule (cortex, from 398 +/- 12 (+/-SE) to 145 +/- 20; outer medulla, from 293 +/- 21 to 112 +/- 14 pmol X mm-1 X h-1); however, it was not altered in any other segment of the nephron. These results demonstrate that kidney NEM-sensitive ATPase is under the control of corticosteroids and suggest that mineralocorticoids rather than glucocorticoids are involved in this regulation that specifically occurs in mineralocorticoid-sensitive nephron segments. This paper also describes a new computerized method for the automatic determination of the length of single nephron segments.

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