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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To define the role of the renal dopaminergic system in the pathogenesis of essential hypertension, urinary free dopamine excretion was examined in 23 normotensive subjects who had one or more first-degree relatives with essential hypertension, and also in 36 matched control subjects without any such family history. The group urinary dopamine excretion and urinary sodium excretion were not different. However, a significant urine dopamine-sodium relationship was apparent in the controls but not in the relatives due to relatively high dopamine output in those with lower sodium excretion. The two groups were similar as regards blood pressure (BP), plasma renin activity (PRA), prolactin and catecholamines. These findings demonstrate an alteration in the urine dopamine-sodium relationship in some normotensive subjects with genetic risk of hypertension.
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PMID:Urinary dopamine excretion in normotensive subjects with or without family history of hypertension. 351 46

The efficacy of bromocriptine in the treatment of hypertension was assessed in a double-blind placebo controlled cross-over study preceded by a dose titration phase. A diuretic and/or a beta-blocker were administered concomitantly in constant dosage to 11 of the 20 patients who received bromocriptine. A wide range of doses of bromocriptine was tolerated. Side-effects of vomiting and postural hypertension did not occur, possibly due to the gradual increase in the administered doses. Plasma prolactin was not raised in this population of hypertensives. In the dose titration phase (n = 20), a small fall in diastolic but not in systolic blood pressure occurred with bromocriptine, but only with the patient standing and after exercise. In the double-blind phase (n = 9), there was no significant difference in blood pressure between the bromocriptine and placebo treatments. It is concluded that bromocriptine was not effective in lowering blood pressure in the present patients with essential hypertension.
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PMID:Bromocriptine in the treatment of hypertension. 351 42

To define the mechanisms whereby clonidine lowers blood pressure, we measured cerebrospinal fluid and plasma levels of norepinephrine, normetanephrine, epinephrine, dopamine, and the dopamine metabolite homovanillic acid in 10 primary hypertensive subjects before and after 3 months of clonidine treatment (mean dose, 0.68 mg/day). Catecholamines were measured by radioenzymatic methods. Cerebrospinal fluid and plasma sampling was performed after subjects had fasted and remained supine overnight, and plasma sampling was repeated 2 hours later, after subjects had ambulated. Supine and upright blood pressure fell, as might be expected. Cerebrospinal fluid levels of norepinephrine and normetanephrine fell significantly, but dopamine and homovanillic acid levels were unchanged. Plasma norepinephrine, normetanephrine, and epinephrine levels decreased 30 to 50%, and supine dopamine levels also fell. The percent fall in supine blood pressure was related to the fall of cerebrospinal fluid and plasma norepinephrine. There were also positive relationships between the decreases of plasma norepinephrine and of normetanephrine and dopamine. The cerebrospinal fluid/plasma norepinephrine ratio was unaffected by clonidine, suggesting that the drug lowered both pools equally. Our findings indicate that clonidine decreases both central and peripheral norepinephrine activity. The dopaminergic activity of cerebrospinal fluid was unaffected by clonidine, and though plasma dopamine levels tended to be lower after treatment, mean plasma prolactin level, an index of dopaminergic activity, was also unchanged. The fall in plasma epinephrine level is probably related to diminished sympathetic adrenomedullary stimulation and is unlikely to contribute to clonidine's antihypertensive action. These results also suggest that measurement of normetanephrine in cerebrospinal fluid and plasma provides a good index of norepinephrine activity.
Hypertension 1986 Jul
PMID:Effects of clonidine on central and peripheral nerve tone in primary hypertension. 372 61

The effect of hypertension in pregnant women on fetal maturation is an issue of considerable importance. Because of a possible role of prolactin in fetal adrenal steroidogenesis and in fetal lung maturation, we have investigated the relationship between hypertension in pregnant women and levels of prolactin and dehydroepiandrosterone sulfate in serum of newborn infants. It was found that with the mild-to-moderate form of pregnancy-induced hypertension (PIH), there was little effect on prolactin levels in newborn serum. In newborns of women with severe PIH, however, serum prolactin levels were significantly greater (p less than 0.01) than those in newborns of women with uncomplicated pregnancies. Conversely, umbilical serum concentrations of dehydroepiandrosterone sulfate in newborns of women with severe PIH were significantly less (p less than 0.05) than those in newborns of women with uncomplicated pregnancies. These findings are supportive of the view that pituitary function and adrenocortical function of fetuses of women with PIH are different from those of fetuses of normotensive women. These findings are suggestive that PIH alters the function of the fetal pituitary and adrenal cortex.
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PMID:Prolactin levels in umbilical cord serum and its relation to fetal adrenal activity in newborns of women with pregnancy-induced hypertension. 374 60

We investigated the effect of arterial baroreceptor deafferentation on serum and pituitary prolactin (PRL) and on catecholamines in median eminence (ME) and anterior and posterior pituitaries. Male Wistar rats were sinoaortic denervated (SAD) or sham operated (SO). Three days after surgery serum prolactin, measured by radioimmunoassay, was suppressed in SAD rats (-54%, P less than 0.05), and dopamine (DA) and norepinephrine (NE) concentrations, measured by radioenzymatic or high-performance liquid chromatography electron capture methods, were significantly reduced in ME of SAD rats (NE, -54% P less than 0.005 and DA, -56% P less than 0.001). Simultaneously, anterior pituitary of SAD rats had significant increases in both catecholamines, whereas posterior pituitary showed no changes. Four hours after surgery serum PRL was also reduced (-40%, P less than 0.05) in SAD rats, but no changes in ME catecholamines were found. Mean arterial pressure (MAP) and heart rate were measured before and after injection of bromocriptine (0.5 mg/kg ip) in SAD and SO rats 3 days after surgery. Bromocriptine markedly suppressed serum PRL in both groups and reduced MAP from 144 +/- 10 to 84 +/- 5 and from 116 +/- 2 to 99 +/- 3 in SAD and SO rats, respectively; heart rate was reduced in SAD rats. We conclude that the SAD rat is a model of hypertension with suppressed serum PRL and that interruption of arterial baroreceptor nerves suppresses PRL secretion probably by modulating tuberoinfundibular turnover of catecholamines.
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PMID:Suppressed serum prolactin in sinoaortic-denervated rats. 381 67

Plasma prolactin level and plasma renin activity were determined in normal subjects and patients with low and normal renin essential hypertension, renal hypertension, renovascular hypertension, primary aldosteronism, Cushing syndrome, pheochromocytoma and malignant hypertension. In both normal subjects and the normal renin essential hypertensives, plasma prolactin was significantly higher in females than in males. Plasma prolactin was also significantly higher in the normal renin essential hypertensives than in normal subjects of both sexes, while no significant difference was found between the low renin group and normal subjects of either sex. A significantly positive correlation was observed between plasma renin activity and the plasma prolactin level in male essential hypertensives, but not in females. Although no significant difference in plasma prolactin level could be detected between patients with secondary hypertension and normal subjects, this level was significantly higher in malignant hypertensives than in normotensives. From these results, it was shown that significant differences of plasma prolactin levels exist between normal renin essential hypertensives, and low renin essential hypertensives or normal subjects, and that these differences may partly depend on renin status which might be related to the central dopaminergic activity. In malignant hypertensives, the high level of plasma prolactin may be caused by diminished renal function, but the suppression of central dopaminergic activity cannot be excluded in the mechanism of plasma prolactin increment.
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PMID:Plasma prolactin levels in patients with essential hypertension, malignant hypertension and secondary hypertension. 388 34

Bromocriptine (2.5 mg/day orally) produced a significant fall in supine mean arterial pressure in nine hypertensive haemodialysis patients with high serum prolactin levels, without causing significant changes in heart rate. On bromocriptine, there was a significant decrease in the mean value of both serum prolactin and plasma noradrenaline, without significant changes in the mean value of plasma renin activity. A significant relationship was found between the changes in supine plasma noradrenaline and the changes in supine mean arterial pressure induced by bromocriptine. The increase in mean arterial pressure in response to the tilt test was greater on bromocriptine than on placebo although the changes in plasma noradrenaline were reduced by bromocriptine. Similar results were observed during the cold pressor test. These findings suggest that the arterial pressure-lowering effect of bromocriptine is related to the reduction in sympathetic out-flow. The parallel decrease in serum prolactin raises the question of the possible involvement of dopaminergic mechanisms in the development of hypertension in our patients. Moreover, bromocriptine seems to enhance the vascular response to endogenous noradrenaline.
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PMID:Effect of bromocriptine treatment on prolactin, noradrenaline and blood pressure in hypertensive haemodialysis patients. 390 10

A symposium of over 125 scientists, held in August 1984 at the campus of Oxford University, considered the latest developments concerning cannabis research. Evidence on the mode of tetrahydrocannabinol action on the central nervous system indicates that acetylcholine turnover in the hippocampus through a GABA-ergic mechanism is of major importance, though the role of the dopaminergic or serotoninergic mechanism and involvement of prostaglandins and c-AMP is not ruled out. The use of cannabis causes prominent and predictable effects on the heart, including increased work-load, increased plasma volume and postural hypotension, which could impose threats to the cannabis users with hypertension, cerebrovascular disease or coronary arteriosclerosis. Cannabis or tetrahydrocannabinol has damaging effects on the endocrine functions in both male and female of all animal species tested. Among possible mechanisms of action, it is suggested that tetrahydrocannabinol disrupts gonadal functions by depriving the testicular cells of their energy reserves by inhibition of cellular energetics, and that it stimulates androgen-binding protein secretion, which may account for oligospermia seen in chronic cannabis smokers. In addition to these direct effects on gonads, tetrahydrocannabinol interferes with hormonal secretions from the pituitary, including luteinizing hormones, follicle-stimulating hormones and prolactin. Research findings indicate that maternal and paternal exposure to cannabinoids can influence developmental and reproductive functions in the offspring, but it is difficult to separate possible teratogenic effects from subsequent gametotoxic and mutagenic potentials of cannabinoids.
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PMID:An update on cannabis research. 391 16

The high concentrations of prolactin (hPRL) in human amniotic fluid appear to be derived principally from maternal decidua. The present study evaluated both the biologic and immunologic activity of amniotic fluid hPRL obtained from normal and selected complicated pregnancies. Biologic and immunologic activities of amniotic fluid hPRL were also compared with lecithin:sphingomyelin ratios and phosphatidylglycerol content. No significant correlation existed between amniotic fluid hPRL activities and fetal lung maturation. However, a significant increase in amniotic fluid hPRL concentration as well as specific biologic activity of the hormone was found in pregnancies complicated by hypertension. These findings suggest alterations in the synthesis of decidual hPRL and/or its transport to the amniotic fluid that may influence pregnancy-induced hypertension.
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PMID:Altered prolactin bioactivity in amniotic fluid of hypertensive pregnancy. 396 20

Human prolactin (PRL) has been related to various pathologic disorders known to be associated with osmoregulation and hypertension. In this study, we compared changes in plasma PRL concentrations in normal pregnant patients to those in patients with severe pregnancy-induced hypertension (PIH). Comparison of plasma PRL concentrations collected antepartum, at delivery, and 48 hours postpartum failed to distinguish women with PIH from those without. Only women with PIH, however, showed a significant rise in systemic PRL concentrations between admission to the study and delivery. Antepartum abnormalities in plasma PRL concentrations associated with PIH may not have been detected because of diurnal variations in PRL secretion.
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PMID:Plasma prolactin concentrations and pregnancy-induced hypertension. 399 2


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