The Potential Role of Selected Endocrine Systems in Aging Processes

Nelson, James F.

doi:10.1002/cphy.cp110115

Cited by 9 publications

(4 citation statements)

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“…We recognize, however, that higher renal medullary eNOS protein abundance is seen in young adult females [31], which is presumably responsible for the findings of Reckelhoff et al [32] who observed more eNOS in whole kidney homogenates from young adult female versus male rats. Since estrogen levels tend to decline with advanced age in females [33], it seems unlikely that estrogens are directly responsible for the maintenance of the constitutive NOS enzymes in the old female kidney. We suggest an alternative mechanism that may explain the gender differences in renal NOS expression in the aging kidney, based on the development of CRD as the initiating factor in reduced renal NOS expression, see below.…”

Section: Discussionmentioning

confidence: 99%

Sexual dimorphism in the aging kidney: Effects on injury and nitric oxide system

Erdely¹,

Greenfeld²,

Wagner³

et al. 2003

Kidney International

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Section: Discussionmentioning

confidence: 99%

Sexual dimorphism in the aging kidney: Effects on injury and nitric oxide system

Erdely¹,

Greenfeld²,

Wagner³

et al. 2003

Kidney International

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“…It is important that appropriate models are carefully selected. Virtually all 'aged' animals (i.e., rodents) are obese; therefore, interpretation of the results may be complicated by marked changes in the endocrine system which are known to occur as weight increases [19]. To exclude questionable outcomes, the animals chosen for the present studies were the Fischer 344 !…”

Section: Introductionmentioning

confidence: 99%

Age-Related Changes in Renal Function, Membrane Protein Metabolism, and Na,K-ATPase Activity and Abundance in Hypokalemic F344 × BNF<sub>1</sub> Rats

Eiam-Ong

Sabatini²

1999

Gerontology

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Background: Potassium depletion is a common electrolyte abnormality in elderly humans, usually as a consequence of diuretic use or poor oral intake. Hypokalemia is associated with a number of changes in renal function and an increase in some renal membrane transporters; its growth-promoting effect in young animals is well known. With aging, the renal adaptation to a number of challenges is often diminished. We hypothesized that aging is related to decreases in renal function, renal membrane protein metabolism, as well as Na,K-ATPase protein abundance and activity in both control animals as well as in those with potassium depletion. Objective: We examined the effects of dietary-induced hypokalemia in true-aged nonobese rats (30 months old) on renal function, cortical brush border membrane (BBM) and basolateral membrane (BLM) protein metabolism, and Na,K-ATPase protein abundance and activity. We compared the results obtained to those seen in their 4-month-old counterparts similarly treated. Methods: Young (4-month-old) and senescent (30-month-old) male Fisher 344 × Brown-Norway F₁ rats (F344 × BNF₁) were fed either a normal or potassium-deficient diet for 7 days. At 24 h, the U-¹⁴C-leucine incorporation was measured for determination of protein metabolism in renal BBM and BLM. Cortical BLM vesicle and microdissected proximal convoluted tubule (PCT) Na,K-ATPase activities were determined along with Western blot analysis of the cortical BLM α₁ subunit of Na,K-ATPase. Metabolic and renal function parameters were also examined. Results: Hypokalemia caused hyperbicarbonatemia, hyperglycemia, and azotemia, but only in the senescent animals. The aged control rats had a higher basal level of urine volume, ammonium excretion, and fractional excretion of chloride. By contrast, aging in the F344 × BNF₁ rats was associated with a decrease in plasma aldosterone (by 35%) and phosphate (by 40%) levels as compared with their young controls. Hypokalemia resulted in a significant reduction of plasma aldosterone and a rise in muscle sodium concentration in both age groups; it significantly increased renal BBM and BLM protein concentrations in the young group, while these parameters remained unchanged in the senescent rats. The aged potassium-depleted animals showed a 14% decrease in BBM protein biosynthesis, but there were no changes in the young hypokalemic rats. Both potassium-depleted elderly and young rats had a significant reduction (by 33%) in BLM protein biosynthesis. Hypokalemia significantly increased the Na,K-ATPase activity in both cortical BLM vesicles and in microdissected PCT. The percentage increase in microdissected PCT segments (Na,K-ATPase activity) in elderly potassium-depleted animals was significantly less than that seen in hypokalemic young ones. Aging, per se, was associated with decreased basal microdissected PCT Na,K-ATPase activity in control animals. Hypokalemia had no effect on cortical BLM α₁ subunit Na,K-ATPase protein abundance in either ...

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“…Several studies have demonstrated a progressive age‐related impairment in energy expenditure. The ageing process is associated to decreased energetic requirements due to a reduction in basal metabolic rate (Goran & Poehlman 1992) and physical activity (Starling 2001), as well as hormonal alterations, mainly of gonadal and growth hormones (Nelson 1995). It is extensively described that food restriction leads to a decrease in the energy expenditure as a mechanism of energy conservation, which is elementary for the animal survival (Luz & Griggio 1991, Munch et al.…”

Section: Discussionmentioning

confidence: 99%

Effects of ageing on the energy balance of food‐restricted rats

Passadore

Griggio

Nunes

et al. 2004

Acta Physiologica Scandinavica

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The Potential Role of Selected Endocrine Systems in Aging Processes

Abstract: The sections in this article are: Hormones and Aging: An Overview Hormonal Alterations During Aging Gonadal Steroids Adrenal Steroids Growth Hormone Summary

Cited by 9 publications

References 209 publications

Sexual dimorphism in the aging kidney: Effects on injury and nitric oxide system

Sexual dimorphism in the aging kidney: Effects on injury and nitric oxide system

Age-Related Changes in Renal Function, Membrane Protein Metabolism, and Na,K-ATPase Activity and Abundance in Hypokalemic F344 × BNF<sub>1</sub> Rats

Effects of ageing on the energy balance of food‐restricted rats

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