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Biomedical subjects

P L Corvol

Publications and source records attributed to P L Corvol.

8 recordsLinked to original sources

Ontogeny of angiotensin II type 2 (AT2) receptor mRNA in the rat.

To study the distribution of the recently cloned angiotensin II type 2 (AT2) receptor in the rat fetus, a double stranded cDNA was generated by a new and recently described methodology requiring no cloning procedure. The cDNA obtained after reverse transcription (RT) and polymerase chain reaction (PCR) amplification corresponded to 500 base pairs of the gene coding sequence, and included the SP6 and T7 promoters at the 5' and 3' end, respectively. 35S-labeled cRNA sense and antisense probes were synthesized by in vitro transcription and used for in situ hybridization. From 13 to 19 days of gestation the AT2 receptor mRNA expression evolved and extended from a series of paired spots located para-axially, which were not identifiable at this level of observation, to a distribution in various mesenchymes (perichondrium, subepidermal layers), muscle cells (tongue, diaphragm, stomach), and classical target organs for Ang II (adrenal gland, kidney, aorta). During the first days after birth, the AT2 receptor mRNA decreased and remained detectable only in the adrenal gland and kidney. The distribution of the AT2 receptor mRNA appeared strikingly different from that of the AT1A receptor, which was studied in parallel for comparison.

Adrenal Glands↗

Influence of previous diuretic intake on the humoral and hormonal profile of idiopathic oedema.

Three groups of women underwent water loading tests: normal subjects, idiopathic oedema patients who had taken no medication for at least 3 months, and a second oedema group with recent diuretic intake. Idiopathic oedema in drug-free patients was characterized by an abnormal capillary permeability, lower basal protein values, a dramatic drop in urinary output in the upright position due to reduced glomerular filtration, enhanced reabsorption of sodium and water and stimulation of aldosterone and antidiuretic hormone (AVP) secretions. In these idiopathic oedema cases, osmolar AVP regulation was disrupted but AVP control by plasma volume was maintained. In the basal state, patients with recent diuretic intake were characterized by a gain in body weight and by depletion of plasma volume and plasma potassium. In these subjects, urinary output in the upright posture was as insufficient as in drug-free patients but was due to higher sodium reabsorption. Renal insensitivity to AVP action was also observed. Osmolar regulation and volume regulation of AVP were both disrupted in these cases with recent diuretic intake.

Adult↗

Volume-dependent parameters in essential hypertension.

Blood pressure, renal blood flow, total blood volume (TBV), plasma renin activity, and vascular reactivities to angiotensin and norepinephrine were studied in 48 normotensive subjects and 106 essential, sustained, hypertensive patients with normal renal function, balanced sodium intake, and urinary output. A significant negative pressure-volume relationship was observed in normal subjects. Among the hypertensive patients, some were inside the 95% confidence limits of the normal curve and the others were above, indicating a disturbance in the pressure-volume relationship. A quantitative evaluation of the pressure-volume disturbance was proposed and discussed. The blood pressure of each hypertensive patient corresponded to two different blood volume values: the renal valve and the theoretical value extrapolated from the normal curve. The difference between the two values was called deltaTBV and was positive in hypertensive patients. The deltaTBV value was negatively correlated with the renal blood flow, the creatinine clearance, the plasma renin activity, and the vascular reactivities to angiotensin and norepinephrine (P less than 0.0001). The parameters were not correlated with the real blood volume. This study demonstrates quantitatively a pressure-volume disturbance in essential hypertension. This disturbance is strongly correlated with the renal function and the renin-angiotensin system changes.

Blood Pressure↗

Relationship of plasma renin activity and aldosterone levels with hemodynamic functions in essential hypertension.

Correlates of plasma renin activity and plasma aldosterone levels with hemodynamic functions were studied in 47 male patients with untreated, permanent essential hypertension. All subjects had a normal creatinine clearance and received a diet of 110 mEq/day of sodium. Supine plasma renin activity was directly correlated with cardiac index (P less than.01) and cardiopulmonary blood volume (P=.01). Percentage changes in plasma renin activity and total peripheral resistance in response to upright position were positively correlated (P less than.001). Supine plasma aldosterone level was directly correlated with stroke index (P less than .001) and negatively correlated with hear rate (P less than .05). No significant correlation of aldosterone level was observed with the other measurements, including plasma renin activity. The study points to the neural sympathetic control of plasma renin activity in essential hypertension and suggests the existence of some interrelationships between aldosterone level and cardiac performance.

Adult↗

Anti-hypertensive adrenergic-blocking agents: effects on sodium balance, the renin-angiotensin system and haemodynamics.

1. The changes in plasma volume, haemodynamic variables, plasma renin activity and plasma aldosterone were studied in forty-one hypertensive patients after administration of adrenergic-blocking agents. Four drugs were used: alpha-methyldopa (fourteen patients), guanethidine (ten patients), clonidine (nine patients) and reserpine (eight patients). Drugs were administered orally during 7 days' hospitalization on a normal sodium diet (110 mmol/day). 2. The four drugs had similar effects: a significant decrease in blood pressure, a significant increase in plasma volume and no change in stroke volume. 3. With alpha-methyldopa and guanethidine, heart rate, plasma renin activity and plasma aldosterone were unchanged. 4. With reserpine and clonidine, heart rate and plasma renin activity were significantly decreased, whereas plasma aldosterone did not change significantly. 5. This study suggests that the decrease in plasma renin activity was related to the lowering of the heart rate rather than to sodium retention and that adrenergic-blocking agents can impair the normal relationship between stroke index and plasma volume, between plasma volume and plasma renin activity, and between plasma renin activity and plasma aldosterone.

Adult↗