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Background: There are numerous data indicating a significant role of the sympathoadrenal system and the reninangiotensin- aldosterone system in the regulation of blood pressure and the pathogenesis of essential hypertension. However, the genetic background of essential hypertension remains unclear., Aim: To determine the effects of genetic factors on selected indicators of the activity of the sympathoadrenal system and the renin-angiotensin-aldosterone system in twins., Methods: We studied 39 monozygotic twin pairs (age 33+/-7 years) and 37 same-gender dizygotic twin pairs (age 36+/-7 years). We measured blood and urine adrenaline (A), noradrenaline (NA), dopamine (DA) and aldosterone (ALD) levels, as well as plasma renin activity (PRA) and serum angiotensin-converting enzyme (ACE) activity. Parameters of the genetic models for age- and gender-adjusted data were estimated by model fitting and path analysis technique using LISREL 8., Results: The effects of genetic factors on the variability of blood and urine catecholamine levels were 69% and 65% for A, 42% and 76% for NA, and 58% and 40% for DA, respectively. We also found shared environmental components for blood NA (28%) and urine DA (17%). Genetic factors accounted for 36% of the variability of PRA and 80% of the variability of ACE. ALD levels were related only to environmental factors (including a shared environmental component, estimated at 25%, for urine ALD)., Conclusions: We found significant effects of genetic factors on the activity of the sympathoadrenal system, as indicated by blood and urine catecholamine levels. We also found the effect of genetic factors on PRA and ACE, but not on aldosterone levels.

We evaluated the effect of captopril treatment on left ventricular mass (LVM) and function in sustained mild-to-moderate primary hypertension. In 16 men aged 34.5 +/- 6.4 yrs. M-mode echo and pulsed wave Doppler recordings were obtained prior to and after 2 months captopril treatment (50-150 mg daily). No significant changes in heart rate, systolic blood pressure, ejection fraction, fractional shortening, cardiac output, LVM and Doppler-derived indices of mitral inflow were observed. Diastolic blood pressure measured during examination fell from 102.2 +/- 13.3 to 90.3 +/- 9 mmHg (p less than 0.026). No consistent correlations between catecholamines and indexes of left ventricular function were found. Two-month captopril therapy in mild-to-moderate hypertension results in diastolic blood pressure lowering with no effect on LVM or left ventricular function.

In the face known antihypertensive action of small dopamine (DA) concentrations, serum free and conjugated dopamine levels were determined during orthostatic impulse. It was also estimated, whether correlation between blood pressure changes and serum dopamine concentration existed under those conditions. 9 patients with borderline hypertension, 8 with fixed hypertension and 5 healthy volunteers (control group) underwent the 10 minute passive tilt up test. It caused significant decrease of free DA concentration in healthy men as well as in those with borderline hypertension and conjugated DA level in both groups of patients with primary hypertension. Blood pressure increased only in patients with borderline hypertension. Most expressed changes in dopamine concentration were also observed in those patients and they only had increased serum DBH activity. Blood pressure changes inversely correlated with changes of serum free and/or conjugated DA levels in the control group and in patients with primary hypertension. Authors stated basing on this study results, that serum DA level lowering caused by the orthostatic impulse can be one of phenomenons enable adaptation for a vertical position.

Serotonin appears to play an important part in the pathogenesis of essential hypertension. Various studies have shown, that the metabolism of serotonin may be disturbed in some pathological conditions for example in hypertension. It concerns also the changed mechanisms of uptake and release of serotonin. The certain blood vessels may become more hypersensitive to the vasoconstrictor effects of serotonin in patients with hypertension than in normal subjects. During chronic treatment with ketanserin, S2-serotonergic antagonist, blood pressure is reduced in spontaneously hypertensive rats and in humans. This fact can also indicate indirectly, that that serotonin plays a part in the pathogenesis of essential hypertension. The aim of the study was to determine the concentration of free serotonin (S) in the blood of 15 patients with sustained essential hypertension in the mean age 32.8 +/- 1.8, of 23 patients with borderline essential hypertension in the mean age 29.0 +/- 3.0 and of 10 normal subjects in the mean age 31.1 +/- 1.7 years. Plasma free serotonin was determined by fluorometric method. All patients and controls were investigated at the hospital. They were on normosodium diet, without drugs for last two weeks. The fasting blood samples were collected in the supine position. Free serotonin blood concentration was significantly higher in hypertensive group than in normal subjects. The important difference of serotonin blood concentration between two groups of hypertensive patients was noticed. It was significantly higher in group of patients with sustained hypertension, than in group with borderline hypertension (p less than 0.05). Our results are similar to the observations of other authors.(ABSTRACT TRUNCATED AT 250 WORDS)

Interrelationship between serum Na+, K+ concentrations and the excretion of norepinephrine (NA), epinephrine (A) in the urine was studied in 69 patients aged 15-69 with pheochromocytoma (PH), and between serum Na+, K+ concentrations and serum NA, A levels in 53 patients. Furthermore, in 15 patients correlation between Na+, K+ concentrations in erytrocytes and serum NA, A levels was estimated. Na+ and K+ concentrations were determined using photometric analysis, NA and A excretion in the urine using fluorometric method and in blood by radiometry. Hypokalemia and hyponatremia were stated in 22% and 19% of patients with PH, respectively. Only in patients with electrolytic disorders correlation of serum as well as erythrocyte Na+ concentrations with serum NA level and between serum K+ and A concentrations were proved. In the part of studied patients with PH, the NA and A excess induced disorders of electrolytic homeostasis.

Atrial natriuretic peptide concentrations (ANP) were determined in 4 patients with pheochromocytoma during its surgical removal. There was no correlation among ANP level, plasma catecholamines concentrations and blood pressure. Increase of plasma ANP concentration after tumor removal can be explained by simultaneously observed hypervolemia. It proves that ANP secretion mostly depends on enlarged central blood volume.

Atrial natriuretic peptide (ANP) activity was studied in 33 males with borderline and established essential hypertension. No significant differences of serum ANP concentration were stated in patients with borderline and established uncomplicated hypertension in comparison with the control group.