Alterations in the secretion of atrial natriuretic factor in atria from aged rats.

Tummala, Pradyumna E.; Dananberg, Jamie; Grekin, Roger J.

doi:10.1161/01.hyp.20.1.85

Cited by 17 publications

(3 citation statements)

References 21 publications

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“…In contrast, Kao et al [12] found that basal plasma ANF levels became progressively elevated as a function of age (1-20 months) in male Wistar rats. Similarly, Korytkowski and Ladenson [11], Tummala et al [13], and Giordano et al [14] reported higher basal plasma ANF levels in 12-to 18-month-old male Wistar rats, in 16-to 24-month-old rats, or in 24-to 26-month-old Fisher rats versus mature (4 months), young (3 months), or adult (4-6 months) animals, respectively. Likewise, age-related increases in plasma ANF levels were observed 24 h fol lowing a high-sodium diet in rats [11].…”

Section: Discussionmentioning

confidence: 85%

Age-Related Changes in Secretion and Metabolic Effects of Atrial Natriuretic Factor in Rats

Rakotondrazafy¹,

Davicco²,

Barlet³

et al. 1996

Gerontology

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The effects of aging on the secretion of and renal sensitivity to atrial natriuretic factor (ANF) were studied concomitantly in both senescent (25- to 34-month-old) and in adult (7- to 13-month-old) female and male Long-Evans rats. The plasma concentrations of ANF, measured in response to either a mild stimulation induced by a hypertonic volume expansion (i.e., 20 min after the onset of a continuous infusion during 15 min of a 2.5% NaCl solution; n = 18 old and 23 adult rats) or an intense stimulation produced by morphine injection (i.e., 30 min after an intraperitoneal injection of 5 mg morphine/100 g body weight; n = 11 old and 12 adult rats), were significantly lower (approximately -34 and -80%, respectively) in old as compared with adult animals. Acute intravenous injection of exogenous rat ANF (0.10 and 0.40μg/l00g body weight) induced similar natriuretic, diuretic, and kaliuretic effects in aged (n = 18) and in adult (n = 23) rats. The present data suggest that the significantly reduced (about -20%) natriuretic and kaliuretic responses of the aged rat, observed 20 min after the onset of hypertonic volume expansion, could be partly due to a primary defect in cardiac production and/or release of ANF rather than to a reduction of renal responsivity to ANF.

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Section: Discussionmentioning

confidence: 85%

Age-Related Changes in Secretion and Metabolic Effects of Atrial Natriuretic Factor in Rats

Rakotondrazafy¹,

Davicco²,

Barlet³

et al. 1996

Gerontology

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“…Evidence for a stimulatory role of the CNS in plasma ANP regulation came from blocking the effect of central ANP, either by central injection of ANP antiserum (Charles et al, 1991) or by lesions of specific hypothalamic areas (AV3V) (Rauch et al, 1990), which could inhibit the plasma ANP response to plasma volume expansion and/or to hypertonic saline infusion. Evidence for the latter comes from the study of Tummala et al (1992), who reported that atria from aged rats has an increased response to phenylephrine compared with young rats, although the secretary response to stretch was less than that of young rats.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Aging on ANP Levels in the Plasma, Heart, and Brain of Rats

Wu¹,

Kwan²,

Tang³

1997

The Journals of Gerontology Series A: Biological Sciences and M

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Atrial natriuretic peptide (ANP) is a hormone important in the cardiovascular system via its regulatory roles in sodium and water excretion, and in vasodilatation. Aging represents a major risk factor in the development of hypertension, a perturbation which may activate compensatory mechanisms. The influence of aging on the ANP levels in plasma, atria, ventricles, hypothalamus, and brainstem was evaluated by comparing young (3 mo), middle-aged (12 mo), and old (24 mo) rats. Plasma and ventricular ANP levels increased with age, while ANP content in the atria as well as hypothalamus decreased significantly. PreproANP mRNA contents increased with age in the ventricle but not in the atrium. It is suggested that the increase in plasma ANP levels in old rats is due to the increase in ANP secretion from the atrium and the ventricle, partly as a result of an increase of release of ANP from hypothalamus.A TRIA from a variety of animal species, including L humans, are characterized by the presence of membrane-bound granules (Jamieson and Palade, 1964) that are involved in opposing the development of hypertension (De Bold et al., 1981). These granules store the precursor of the atrial natriuretic peptide (ANP), a 28 amino acid peptide hormone which is synthesized and released by the atria. Several other tissues, including lung, liver, intestine (Gardner et al., 1986), and brain (Gardner et al., 1987), also synthesize small amounts of the peptide.It is well known that aging is associated with cardiovascular and endocrine disorders (Yoshikawa and Beck, 1990), and thus much attention has been paid to the etiology of cardiovascular consequences associated with aging (Julius and Schork, 1971;Berkman and Seeman, 1986). Agerelated changes of ANP have been associated with the dysfunction of the vasomotor tone and body fluid homeostasis. The plasma concentration of ANP has recently been reported to increase in older adult rats (12-18 mo) versus younger rats (2-4 mo) (Korytkowski and Landenson, 1991). The source of the increased plasma ANP levels with aging appears to be the heart (Giordan et al., 1993). As the atrium and the ventricle are important sources of ANP in the plasma, and ANP in the central nervous system may be involved in the regulation of peripheral ANP release (Charles et al., 1991), we have examined the ANP contents in the atria and the ventricle as well as the brain, and correlated these to the plasma ANP levels in young, middleaged, and old rats. METHODSAnimals. -Male Sprague-Dawley rats aged 3, 12, and 24 months (young, adult, and old) were housed at a constant temperature (22 °C) on a 12-h dark-light cycle. Food and water were freely available.Radioimmunoassay (RIA). -To assay tissue immunoreactive ANP concentration, the atrium, ventricle, hypothalamus, and brainstem were dissected from decapitated rats, quickly frozen on dry ice, and stored at -70 °C. Tissues were homogenized in 2 N acetic acid and boiled for 10 minutes. Aliquots of 50 ul of homogenate were aspirated for protein assay. The remaining homogenate w...

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“…In addition, the hormonal status is also modified and is characterized by a decrease of plasma angiotensin II (Ang II), renin, angiotensinogen (ANG),9 and total triiodothyronine concentrations10 and elevated cortisol and atrial natriuretic factor (ANF) levels, at least in humans. [11][12][13] Recent data demonstrate that, in young adult rats, the myocardium is able to synthesize Ang II from ANG and angiotensin-converting enzyme (ACE).14 Pressure overload results in an increased accumulation of both ANG and ACE mRNAs15, 16 and also in an increased synthesis of ANF, 17,18 suggesting that these gene transcriptions could be activated by mechanical triggers.…”

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confidence: 99%

Activation of angiotensinogen and angiotensin-converting enzyme gene expression in the left ventricle of senescent rats.

1994

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BACKGROUND During senescence, the plasma angiotensin II concentration is decreased, but the regulation of intracardiac angiotensin II synthesis has never been investigated. The purpose of this work was to determine the cardiac content of both angiotensinogen (ANG) and angiotensin-converting enzyme (ACE) mRNAs in 24-month-old Wistar rats. METHODS AND RESULTS Total cardiac RNAs and known amounts of ANG and ACE mRNA transcripts, used as standards, were hybridized on slot blots with specific cDNA probes. The quantities of ANG and ACE mRNA were evaluated from the regression lines obtained with fragments of ANG and ACE mRNA in vitro transcripts. With aging, while the overall plasma renin-angiotensin system (RAS) activity decreased, in the left ventricle (LV) the amounts of ANG and ACE mRNAs were increased by fivefold (P < .01) and 2.5-fold (P < .01), respectively, compared with young adult controls. By contrast, in the right ventricle (RV) the same mRNA levels remained unchanged. In parallel, we also found an enhanced expression of the atrial natriuretic factor (ANF) in the LV but not in the RV. CONCLUSIONS During senescence, the depressed circulating RAS activity is in contrast to the increase of both ANG and ACE mRNA levels in the LV. Such an upregulation in both gene activities is more likely to be related to the age-associated changes in arterial compliance rather than to hormonal changes, since (1) this regulation is found only in the LV and (2) the same pattern of regulation is also observed for the ANF mRNA level.

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Alterations in the secretion of atrial natriuretic factor in atria from aged rats.

Cited by 17 publications

References 21 publications

Age-Related Changes in Secretion and Metabolic Effects of Atrial Natriuretic Factor in Rats

Age-Related Changes in Secretion and Metabolic Effects of Atrial Natriuretic Factor in Rats

The Effect of Aging on ANP Levels in the Plasma, Heart, and Brain of Rats

Activation of angiotensinogen and angiotensin-converting enzyme gene expression in the left ventricle of senescent rats.

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