Time course of aldosterone and corticosterone plasma levels in rats during general anaesthesia and abdominal surgery

Fromm, Michael; Oelkers, W.; Hegel, Ulrich; Lüderitz, Sieglinde; Harendt, H.

doi:10.1007/bf00652747

Cited by 32 publications

(14 citation statements)

References 26 publications

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“…In contrast, potassium excretion was uniformly increased after anaesthesia. It seems possible that these events might have been connected with anaesthesiainduced increases in plasma aldosterone concentration (Fromm, Oelkers & Hegel, 1983) which could have contributed both to the promotion of potassium excretion and to the apparent increase in fractional distal sodium reabsorption. The associated increase in fractional distal water reabsorption (1 -V/CL) might have been a consequence of raised vasopressin levels following surgery (Bonjour & Malvin, 1970); the observed increases in urine osmolality accord with this hypothesis.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Anaesthesia and Standard Clearance Procedures on Renal Function in the Rat

1989

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SUMMARYRenal function was assessed in unrestrained conscious rats during either their active period (i.e. the hours of darkness) or their inactive period. On the following day, measurements were repeated after Inactin anaesthesia and preparation for clearance studies. In rats anaesthetized during their active period, preparation for clearance studies had no effect on inulin clearance (used as a measure of glomerular filtration rate), lithium clearance (used as an estimate of endproximal fluid delivery) or fractional lithium excretion. In rats anaesthetized during their inactive period, the same procedures resulted in increases in all three variables, to reach values indistinguishable from those in animals studied during their active period. In both groups of rats there were increases in the fractional reabsorption of sodium and water in the distal nephron and in the urinary excretion of potassium. It is concluded that in anaesthetized rats prepared for clearance studies, rates of glomerular filtration and proximal tubular reabsorption (as indicated by lithium clearance) are similar to those in conscious animals during their active period.

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Section: Discussionmentioning

confidence: 99%

The Effect of Anaesthesia and Standard Clearance Procedures on Renal Function in the Rat

1989

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“…2). Additional experiments, performed in previously adrenalectomized rats to avoid the aldosterone surge incident to the surgical procedure (22), examined the early effects of the hormone on CCT Na-K-ATPase. In these animals both doses of aldosterone employed produced a definite stimulation of enzyme activity after 24 h, but only the higher dose elicited a significant increment after 12 h (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Because the evaluation of short-term effects of aldosterone in intact animals is complicated by the increased endogenous production of this hormone due to the stress of surgery and anesthesia (17,22), the following studies were done in adrenalectomized rats.…”

Section: Short-term Effect Of Aldosterone (Adrenalectomized Rats)mentioning

confidence: 99%

Modulation of renal sodium-potassium-adenosine triphosphatase by aldosterone. Effect of high physiologic levels on enzyme activity in isolated rat and rabbit tubules.

Mujais¹,

Chekal²,

Jones³

et al. 1985

J. Clin. Invest.

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The purpose of this study was to determine the nephron site, time course, and mechanism of mineralocorticoid action on renal tubular Na-K-ATPase in rats and rabbits, without dietary manipulation and by using the natural mineralocorticoid aldosterone. Sustained, high physiologic levels of circulating aldosterone mimicking those produced endogenously during potassium loading or sodium deprivation were provided by constant delivery of the hormone in doses of 5 or 50 ,ug/100 g body wt per 24 h, respectively, from osmotic minipumps implanted subcutaneously.In adrenal-intact rats receiving the 5-ag dose, aldosterone levels were similar to those seen in animals fed a high K diet and produced a time-dependent increase in Na-K-ATPase activity in the cortical-collecting tubule (CCT) to a level 103% higher than in controls after 7 d (2,007±178 vs. 989±72 pmol/ mm per h, P < 0.001); the enzyme activity in the proximal convoluted tubule, medullary thick ascending limb, and the inner stripe of the medullary-collecting tubule did not change significantly. The increment in CCT Na-K-ATPase was larger (142%) in animals receiving for the same period of time the 50-,ig dose, which produced circulating aldosterone levels similar to those of sodium-deprived rats. A significant stimulation of Na-K-ATPase activity was seen in the CCT of adrenalectomized rats after 24 h of treatment with either dose of the hormone, and at 12 h only in animals receiving the 50 ,ug/100 g per 24 h regimen. To determine whether the enhanced Na-K-ATPase activity produced by aldosterone is due to synthesis of new enzyme units or to alteration in its kinetics, we examined the ouabain-binding capacity and the affinity for Na and K of the enzyme from CCT of rabbits treated with 5 ,ug/100 g body wt per 24 h aldosterone for 3 d. These experiments revealed a parallel increment on Na-K-ATPase activity and specific V3Hjouabain binding in aldosterone-treated rabbits, while the affinity of the enzyme for either sodium or potassium was unaltered.

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“…Plasma aldosterone levels of 5 to 10 ng/dl increase transmural PD to 20-30 mV in adrenalectomized rats (47). With anesthesia and intestinal perfusion in intact rats aldosterone levels rise to 63-119 ng/dl accompanied by marked increases in distal colon transmural PD (26). Corticosterone levels at least double under these stimuli.…”

Section: Discussionmentioning

confidence: 97%

“…Adrenalectomized rats were used in this study to eliminate variability in endogenous steroid production (26,45,46). Plasma aldosterone levels of 5 to 10 ng/dl increase transmural PD to 20-30 mV in adrenalectomized rats (47).…”

Section: Discussionmentioning

confidence: 99%

Regulation of cation transport by low doses of glucocorticoids in in vivo adrenalectomized rat colon.

Bastl¹

1987

J. Clin. Invest.

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A dose response curve for glucocorticoid-induced proximal and distal colonic cation transport in vivo was established in adrenalectomized rats. All doses (0.5-50 nmol/100 g body wt) stimulated sodium absorption. Distal sodium absorption did not saturate at dexamethasone levels that saturate the glucocorticoid receptor but also bind to > 35% of aldosterone receptors. Saturation of the pure glucocorticoid response occurred in both segments with RU26988, a synthetic glucocorticoid that does not occupy aldosterone receptors. Maximum velocities for pure glucocorticoid-induced sodium absorption were 15 and 16 teq/min per g dry tissue, and Michaelis constants (K.) were 4.2 and 4.6 X 10-' mol/liter for proximal and distal colon. Ks are similar to the dissociation constant for the colonic glucocorticoid receptor and too low for significant aldosterone receptor occupancy. Dexamethasone increased sodium absorption significantly within 30 min of injection, suggesting the response is not dependent on new protein synthesis. Similar time and dose responses in proximal and distal colon suggest glucocorticoids stimulate the same pathway in both segments.

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Time course of aldosterone and corticosterone plasma levels in rats during general anaesthesia and abdominal surgery

Cited by 32 publications

References 26 publications

The Effect of Anaesthesia and Standard Clearance Procedures on Renal Function in the Rat

The Effect of Anaesthesia and Standard Clearance Procedures on Renal Function in the Rat

Modulation of renal sodium-potassium-adenosine triphosphatase by aldosterone. Effect of high physiologic levels on enzyme activity in isolated rat and rabbit tubules.

Regulation of cation transport by low doses of glucocorticoids in in vivo adrenalectomized rat colon.

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