Plasma Cortisol and Adrenal Ascorbic Acid Levels after ACTH Treatment with a High Intake of Ascorbic Acid in the Guinea Pig

Laney, Pamela H.; Levy, Janet; Kipp, Deborah E.

doi:10.1159/000177573

Cited by 17 publications

(8 citation statements)

References 13 publications

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“…Last, similarly to earlier findings (60), ACTH treatment did not influence plasma ascorbic acid concentrations. Taken together these data indicate that the absolute concentration of ascorbic acid within the adrenal gland is not critical for the synthesis of cortisol (63). While ascorbic acid is required for the synthesis of cortisol, ascorbic acid does not appear to be released simultaneously with cortisol as a stress response.…”

Section: Ascorbic Acid and Cortisolmentioning

confidence: 73%

“…In another study by the same group, the vitamin C content of diets fed to guinea pigs was manipulated, injections of ACTH were administered to the animals, and the resultant alterations in adrenal ascorbic acid and plasma cortisol concentrations were measured (63). Although dietary vitamin C strongly influenced the concentration of ascorbic acid in the adrenal glands, it was without effect on basal or ACTH-stimulated changes in plasma cortisol.…”

Section: Ascorbic Acid and Cortisolmentioning

confidence: 99%

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Vitamin C: Effects of Exercise and Requirements with Training

Peake¹

2003

International Journal of Sport Nutrition and Exercise Metabolism

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Ascorbic acid or vitamin C is involved in a number of biochemical pathways that are important to exercise metabolism and the health of exercising individuals. This review reports the results of studies investigating the requirement for vitamin C with exercise on the basis of dietary vitamin C intakes, the response to supplementation and alterations in plasma, serum, and leukocyte ascorbic acid concentration following both acute exercise and regular training. The possible physiological significance of changes in ascorbic acid with exercise is also addressed. Exercise generally causes a transient increase in circulating ascorbic acid in the hours following exercise, but a decline below pre-exercise levels occurs in the days after prolonged exercise. These changes could be associated with increased exercise-induced oxidative stress. On the basis of alterations in the concentration of ascorbic acid within the blood, it remains unclear if regular exercise increases the metabolism of vitamin C. However, the similar dietary intakes and responses to supplementation between athletes and nonathletes suggest that regular exercise does not increase the requirement for vitamin C in athletes. Two novel hypotheses are put forward to explain recent findings of attenuated levels of cortisol postexercise following supplementation with high doses of vitamin C.

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Section: Ascorbic Acid and Cortisolmentioning

confidence: 73%

Section: Ascorbic Acid and Cortisolmentioning

confidence: 99%

Vitamin C: Effects of Exercise and Requirements with Training

Peake¹

2003

International Journal of Sport Nutrition and Exercise Metabolism

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“…Few studies have investigated the influence of vitamin C on immune responses following intense endurance exercise. Vitamin C is highly concentrated in the adrenal cortex, and it has been hypothesized that vitamin C supplements may influence serum cortisol release and alterations in immune function following heavy exertion (Enwonwu et al 1995;Kodama et al 1994;Laney et al 1990;Redmann et al1995). In some animal models, vitamin C depletion has been associated with a significant increase in serum cortisol without an increase in adrenocorticotrophic hormone (ACTH) (Enwonwu et al 1995;Redmann et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Influence of vitamin C supplementation on oxidative and salivary IgA changes following an ultramarathon

et al. 2003

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This randomized study measured the influence of vitamin C ( N=15) compared to placebo ( N=13) supplementation on oxidative and salivary immunoglobulin A (sIgA) changes in runners competing in an ultramarathon race. Seven days prior to the race, subjects ingested in randomized, double-blind fashion three 500-mg tablets of vitamin C or placebo each day. On race day, blood and saliva samples were collected 1 h pre-race, after 32 km of running, and then again immediately post-race. During the race, runners received 1 l/h carbohydrate beverages (60 g/l) with vitamin C (150 mg/l) or without in a double-blinded fashion. The runners also ingested two to three carbohydrate gel packs per hour (25 g each). Subjects in both groups ran a mean of 69 km (range 48-80 km) in 9.8 h (range 5-12 h) and maintained an intensity of approximately 75% maximal heart rate (HR(max)) throughout the ultramarathon race. Plasma ascorbic acid was higher in the vitamin C compared to placebo group pre-race, and increased significantly in the vitamin C group during the race [post-race, 3.21 (0.29) and 1.28 (0.12) microg/100 microl, respectively, P<0.001]. No significant group or interaction effects were measured for lipid hydroperoxide and F(2)-isoprostane, but both oxidative measures rose significantly during the ultramarathon race. Saliva volume, sIgA concentration, sIgA secretion and sIgA:saliva protein ratio all decreased significantly (P<0.001) during the race, but the pattern of change in all saliva measures did not differ significantly between groups. No significant correlations were found between post-race plasma vitamin C, oxidative, and saliva measures, except for a positive correlation between post-race serum cortisol and serum vitamin C (r=0.50, P=0.006). These data indicate that vitamin C supplementation in carbohydrate-fed runners does not serve as a countermeasure to oxidative and sIgA changes during or following a competitive ultramarathon race.

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“…Yanagibashi et al [15] found in bovine glomerulosa cells, that ascorbate and NADPH provides operative risk from etomidate induced adrenocortical suppression has to be discussed with caution, as corti-reductive equivalents that only support the last step in aldosterone synthesis. Laney et al [16] examined sol depletion is incomplete. the influence of ascorbic acid intake on plasma cortisol and tissue ascorbate levels after ACTH treatment in guinea pigs.…”

Section: Resultsmentioning

confidence: 99%

The role of ascorbic acid and xylitol in etomidate-induced adrenocortical suppression in humans

et al. 1996

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Etomidate-induced suppression of cortisol biosynthesis is a result of a blockade of 11-beta-hydroxylation in the adrenal gland, mediated by the imidazol radical of etomidate. Since the generation of steroids requires reductive and energy rich equivalents, the present study examined whether supplementation with ascorbic acid or xylitol, a major source of NADPH, could attenuate adrenal suppression by etomidate in human subjects by promoting the turnover rate of 11-beta-hydroxylase. During continuous etomidate/alfentanil anaesthesia for pelviscopic surgery 30 female patients received either Ringer's lactate, xylitol (0.25 g kg-1 h-1) or ascorbic acid (0.5 g h-1) intravenously (i.v.). The plasma concentrations of cortisol, aldosterone and dehydroepiandrosterone (DHEA) were recorded for 5 h after end of surgery and a stimulation with synthetic ACTH was performed. The results showed no evidence of a clinically relevant attenuating effect of ascorbic acid or xylitol on etomidate-induced adrenocortical suppression. However, the observed suppression of cortisol levels was not enough to allow an attenuating affect to be measured.

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Plasma Cortisol and Adrenal Ascorbic Acid Levels after ACTH Treatment with a High Intake of Ascorbic Acid in the Guinea Pig

Cited by 17 publications

References 13 publications

Vitamin C: Effects of Exercise and Requirements with Training

Vitamin C: Effects of Exercise and Requirements with Training

Influence of vitamin C supplementation on oxidative and salivary IgA changes following an ultramarathon

The role of ascorbic acid and xylitol in etomidate-induced adrenocortical suppression in humans

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