PubMed Health⌕ Search

Biomedical subjects

R De Châtel

Publications and source records attributed to R De Châtel.

4 recordsLinked to original sources
PubMed1994

Atrial natriuretic peptide (ANP) responsiveness in patients with hypothyroidism.

Hypothyroidism is known to be associated with abnormalities of kidney function; recently, low atrial natriuretic peptide (ANP) plasma levels have been reported. Aim of the study was to asses ANP, sodium and water responsiveness to an acute saline load. Twelve patients with established primary hypothyroidism and 9 control subjects were studied. ANP was determined in plasma by RIA with extraction, prior to and after the infusion of saline, 500 ml/h for 4 hours. On a similar albeit liberal sodium diet hypothyroid patients excreted less sodium and water (74 +/- 33 (SD) mumol/min and 0.69 +/- 0.15 ml/min, respectively) than control subjects (110 +/- 52 mumol/min; P < 0.05 and 1.06 +/- 0.53 ml/min; P < 0.025, respectively). However, the infusion of saline resulted in a 3-fold increase of sodium output and more than 2-fold increase in urine flow. The exaggerated responsiveness in sodium excretion in patients with hypothyroidism was associated with significantly decreased pre-infusion ANP plasma levels (16.1 +/- 11.1 pg/ml vs. 44.4 +/- 14.4 pg/ml; P < 0.001) and also with sluggish response to the volume expansion (+24% vs. +48%). A significant correlation was found between serum T4 levels and plasma ANP concentrations in 8 patients (r = 0.689; P < 0.05). Although hypothyroid patients tend to retain sodium on a liberal salt diet, their kidney is capable of vigorously eliminating excess sodium when challenged with an acute saline load. This exaggerated responsiveness of sodium excretion can be demonstrated in spite of a sluggish response in ANP. Subnormal ANP levels in hypothyroidism are probably the result of thyroid deficiency.

Adult↗
PubMed1992

Body sodium, atrial natriuretic peptide and blood pressure in diabetes mellitus.

Diabetes mellitus (DM) is frequently associated with hypertension for which an independent pathomechanism has been suggested. We studied 26 patients with insulin-dependent (IDDM) and 18 patients with non-insulin-dependent (NIDDM) uncomplicated DM; all patients were in metabolic balance and none of them had hypertension. Exchangeable body sodium (NaE was estimated by isotope dilution, using appr. 1.1 Mbq 24NA. In a subset of 8 IDDM and 8 NIDDM patients atrial natriuretic peptide (ANP) plasma concentration was determined prior to and after the infusion of 2000 ml physiological saline over 2 hr. NaE was significantly increased both in IDDM and NIDDM patients (104.4 +/- 11.4% and 109.9 +/- 8.0% of the normal value for healthy subjects of identical body surface area; p < 0.05 and < 0.001 resp.). Mean blood pressure (MBP) correlated significantly with NaE in both groups (r = 0.364 and r = 0.520; p < 0.05 and < 0.025, resp.) but not in healthy control subjects (r = 0.112; N.S.). Resting ANP levels were not significantly different in IDDM (34.9 +/- 11.3 pg/ml), NIDDM (42.6 +/- 11.7 pg/ml) or control subjects (40.9 +/- 17.2 pg/ml) however the infusion of saline resulted in a significantly greater increase of plasma ANP in the NIDDM patients (to 82.9 +/- 43.2 pg/ml; P < 0.01) than in the controls (55.6 +/- 23.7 pg/ml; P < 0.01) which was associated with a significantly less increase in sodium excretion (UNAV) in the NIDDM patients (+86% vs. 3170%; P < 0.02) indicating down-regulation of ANP receptors in the kidney of NIDDM patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1976

Hypertension associated with early stage kidney disease. Complementary roles of circulating renin, the body sodium/volume state and duration of hypertension.

Interrelations among blood pressure, exchangeable sodium, blood volume and plasma renin activity were studied in 40 normal subjects and in 40 patients with early stage kidney disease (mean plasma creatinine, 2 mg/100 ml). Findings in eight normotensive patients did not differ significantly from those in normal subjects. However, 32 hypertensive patients showed increases (p less than 0.05) in mean exchangeable sodium and in the products of the logarithm of plasma renin activity and exchangeable sodium or blood volume. In normal subjects, blood pressure did not correlate with any of the parameters measured. In the patients, it correlated significantly (p less than 0.05) with duration of hypertension (r = 0.70), exchangeable sodium (r = 0.34) and with sodium-renin (r = 0.38) or volume-renin (r = 0.30) products, but not with blood volume or circulating renin individually. Multiple regression analysis with blood pressure as a dependent variable, and duration of hypertension and the sodium-renin or volume-renin products as independent variables, revealed correlation coefficients of 0.77 and 0.76, respectively. These findings suggest that hypertension accompanying early stage kidney disease may depend at least partly on subtle abnormalities in the sodium volume-renin feedback mechanism as well as on a factor related to the duration of preexisting hypertension.

Adult↗