Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypertension is often accompanied by abnormalities of calcium homeostasis, including hyperparathyroidism with reduced target organ responses to PTH in kidney and bone. Due to this association between PTH and hypertension and since PTH and the paracrine factor PTH-related protein (PTHrp) have both been shown to exert marked changes in cardiovascular activity, these actions of PTH and PTHrp were examined in spontaneously hypertensive rats (SHR) and in control normotensive Wistar-Kyoto rats (WKY). Fourteen-week-old SHR [systolic blood pressure (SBP), 201 +/- 4.4 mm Hg] and WKY (SBP, 141 +/- 2.5 mm Hg) were studied. Renal cortical membranes were prepared and assayed for radioligand binding with [125I]PTH-(1-34) and [125I]PTHrp-(1-34). There was no apparent alteration in the affinity of the binding sites to either peptide in the SHR, but specific binding in SHR renal tissue was only 60% of that observed in WKY tissue for both peptides. Serum immunoreactive PTH levels were 4-fold higher in SHR than WKY, while serum total calcium and 1,25-dihydroxyvitamin D3 levels were not different. The iv administration of both PTH and PTHrp produced dose-dependent reductions in SBP and increases in heart rate in conscious unrestrained SHR and WKY. Both peptides caused greater absolute reductions in blood pressure in SHR than in WKY. However, when the hypotensive response was normalized for the higher baseline pressure in the SHR, the blood pressure reductions caused by PTH and PTHrp were not different in SHR and WKY. Conversely, the chronotropic responses to PTH and PTHrp were lower in SHR compared to WKY. These findings indicate that the SHR exhibits elevated PTH levels, with a reduced number of renal PTH/PTHrp receptors and a depressed chronotropic response to either PTH or PTHrp. In contrast, the hypotensive response to PTH or PTHrp was not altered, indicating possible tissue-specific receptor subclasses or tissue-specific regulation of PTH and PTHrp receptors.
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PMID:Cardiovascular responsiveness to parathyroid hormone (PTH) and PTH-related protein in genetic hypertension. 131 38

In a 20 year period, from 1971 through 1991, 105 chromaffin tumours--excluding cervical ones--were operated by the same surgeon: 50 during the first 15 years and 55 during the last 5 years. Pheochromocytomas are defined as intra-adrenal chromaffin tumours, and paragangliomas--or ectopic pheochromocytomas--as of extra-adrenal location. Among those tumours, 30 were malignant (i.e. metastatic) and 75 benign. Among the 30 malignant tumours, 14 were ectopic, 2 occurred in a MEN II A setting and were bilateral, 2 were associated with liver adenoma and liver hemangioma respectively suggesting Von Hippel-Lindau syndrome, and one case was associated with a seemingly sporadic primary hyperparathyroidism. 9 out of those 30 malignancies were not associated with hypertension. Among 75 benign pheochromocytomas or paragangliomas, 10 were ectopic, 7 occurred in a MEN setting (6 type II, 1 type I). 3 patients without evidence of MEN or other neuroectodermal abnormalities presented bilateral pheochromocytoma, either synchronous (2) or metachronous (1). 7 cases occurred in a Von Hippel-Lindau syndrome (3 bilateral) and 4 in a neurofibromatosis setting (1 bilateral). 3 other cases were familial without evidence of MEN (including a case of triple tumour: bilateral and ectopic and another ectopic case). 2 other cases were associated with seemingly sporadic hyperparathyroidism. As a whole, in 34 of 75 benign pheochromocytomas or paragangliomas, the tumour was not intra-adrenal, unilateral and sporadic. Among those 75 tumours, 22 were not overtly hypertensive, including 10 out of the 41 seemingly intra-adrenal, solitary and sporadic. The pheochromocytoma, benign, intra-adrenal sporadic, hypertensive accounts for no more than 30% of the subphrenic catecholamine-secretin chromaffin tumours.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Can pheochromocytoma be considered a benign unilateral intra-adrenal sporadic hypertensive tumor ? Reflections on a series of 105 surgically treated subdiaphragmatic chromaffin tumors]. 134 86

Primarily hypervolaemic, high output forms of hypertension, with features indicating or strongly suggesting fluid overload as the cause of elevated cardiac output, resulting from renal disease with reduced glomerular filtration rate causing sodium retention, renal tubular causes of sodium retention, greatly excessive sodium intake and low renin hypertension, can be treated by reduction of sodium intake and potentiation of its excretion by diuretic therapy, removal of the cause (e.g. aldosteronoma), and calcium antagonists. Excessive vasoconstriction resulting from noradrenaline (norepinephrine) in neurogenic hypertension, phaeochromocytoma, orthostatic hypertension and alpha-adrenergic drug administration; angiotensin excess due to renal ischaemia brought about by aortic coarctation, renal arterial and arteriolar stenosis, intraluminal obstruction, external renal compression, renin-producing tumours, intrinsic kidney diseases and excessive renin substrate; and vascular structural disorders such as atherosclerosis, arteriolitides and fibrosis with or without calcification of major arteries may also induce hypertension. Secondary hypertension of uncertain mechanism may occur in hyperparathyroidism, hyper-or hypothyroidism, or acromegaly. All are best treated by appropriate correction of the endocrine excess or deficiency. It may also occur in pregnancy, where the mechanism may involve prostaglandin-thromboxane imbalance or calcium deficiency; calcium deficiency with some evidence of benefit from calcium supplements; and the recumbent hypertension paradoxically associated with autonomic failure. Excellent responses to specific correction of the underlying cause or pathogenetic mechanism is usual in young individuals but less frequent in older patients.
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PMID:Secondary hypertension. An overview of its causes and management. 137 54

Recently, a parathyroid hypertensive factor was postulated to play a role in the pathogenesis of hypertension in genetically hypertensive rats. Therefore it was examined, whether in human parathyroid glands a vasopressor substance can be detected. For this purpose, homogenates of hyperplastic parathyroid glands from 20 patients with tertiary hyperparathyroidism were deproteinized and fractionated by gel chromatography. The fractions obtained were tested for vasopressor activity in isolated perfused rat kidneys. A vasopressor fraction containing substances of 0.6-2.5 kDa was identified in the parathyroid glands. The responsible product was heat sensitive, peptidase-, trypsin- and carboxypeptidase y- sensitive and hydrophilic, as it did not bind to hydrophobic reversed-phase gel. These results suggest that parathyroid glands contain a hydrophilic peptide-like vasopressor substance different from the parathyroid hormone.
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PMID:A vasopressor factor partially purified from human parathyroid glands. 141 52

Recent evidence suggests a pathogenetic link between hypertension and insulin resistance. In addition, disturbances of vitamin D/parathyroid hormone axis have been reported in various hypertensive and insulin-resistant states. Chronic renal failure is characterized by high incidence of hypertension, insulin resistance and disturbances in the vitamin D/parathyroid hormone axis. Preliminary studies in both patients and rats with end-stage renal disease who were hypertensive, insulin resistant and 1,25-dihydroxycholecalciferol deficient with hyperparathyroidism; parenteral administration of pharmacological doses of 1,25-dihydroxycholecalciferol led to reversal of hypertension and insulin resistance without significant changes in serum calcium or parathyroid hormone concentrations. Thus, vitamin D deficiency may be an important factor in the pathogenesis of hypertension and insulin resistance in end-stage renal disease.
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PMID:The vitamin D/parathyroid hormone axis in the pathogenesis of hypertension and insulin resistance in uremia. 146 50

Some secondary forms of hypertension are characterized by an abnormal circadian blood-pressure rhythm. Therefore, the circadian blood-pressure variability was investigated in a prospective study using ambulatory blood-pressure monitoring in patients with hyperthyroidism and in patients with primary hyperparathyroidism. Both endocrine disorders are often associated with hypertension. Out of 17 patients with hyperthyroidism 73% were hypertensive, and out of 15 patients with hyperparathyroidism 80% were hypertensive. The blood-pressure profiles were compared to profiles from controls comprising normotensive subjects and patients with essential hypertension. The patients with hyperthyroidism and hypertension had a blunted circadian blood-pressure curve with only a small nocturnal reduction of systolic and diastolic blood pressure as compared to control patients. In patients with hyperthyroidism and normal blood pressure, the circadian blood-pressure rhythm was normal; however, in these patients the circadian heart-rate curve was blunted. All patients with hyperparathyroidism (with and without hypertension) had a normal circadian blood pressure and heart-rate rhythm. From these observations we conclude that in hyperthyroidism the circadian regulation of blood pressure or heart rate is significantly blunted. The circadian blood pressure and heart-rate curve is normal in primary hyperparathyroidism.
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PMID:[Circadian blood pressure rhythm in hyperthyroidism and primary hyperparathyroidism]. 151 9

Parathyroid carcinoma is a rare tumor responsible for 0.5-5% of primary hyperparathyroidism. It is usually small (not more than 27 g) and the precise diagnosis of malignancy is made when local or distant metastases are found. We describe a case of a 37 yr old male presenting with a substernal goiter and no specific symptoms except hypertension. This mass had cysts and calcifications and it was in the anterior upper mediastinum. The patient had severe hypercalcemia (Ca greater than 14 mg/dl), high PTH levels and mild renal failure. Bone scanning showed signs of hyperparathyroidism. The patient was subjected to total thyroidectomy and removal of the mass en block. The tumor was circumscribed lobulated and mostly cystic. It weighed 1,200 g (380 g after evacuation of cysts) and measured 12 x 9 x 4.5 cm. Histologic examination showed a highly differentiated adenocarcinoma of parathyroid with metastasis in a regional lymph node. Almost 4 years later the patient is alive and well without hypercalcemia and without evidence of distant metastases.
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PMID:Large parathyroid functioning carcinoma (1,200 g) presenting as a substernal goiter. 156 Jan 89

Primary hyperparathyroidism (HPT) has been associated with hypertension, hyperinsulinaemia, hypertriglyceridaemia and hyperuricaemia. In the present study, plasma ionized calcium (Ca2+) was studied in relation to cardiovascular risk factors in 20 subjects with mild hypertension. Plasma Ca2+ was found to be negatively correlated with fasting serum insulin, triglycerides and urate, and with diastolic blood pressure (DBP). However, after the interaction of the different risk factors had been taken into account in the multiple regression analysis, only the relationship between Ca2+ and serum insulin was significant (r = 0.55, P less than 0.01). In a previous double-blind, placebo-controlled study 1 micrograms alphacalcidol, a synthetic analogue of 1,25 dihydroxy-vitamin D3, induced a decrease in blood pressure in mild HPT subjects. In the present study, the highest dose that did not further aggravate the hypercalcaemia was given in a long-term study over a 12-month period to 18 mild HPT subjects (average dose, 1.75 micrograms daily). The treatment induced a reduction in body weight of 0.9 kg (P less than 0.05) and an increase in serum urate from 330 +/- 92 to 380 +/- 104 mmol l-1 (P less than 0.01). A reduction in blood pressure was only observed at the end of the study, from 142 +/- 17/86.6 +/- 9.1 to 139 +/- 13/82.9 +/- 8.9 mmHg (P less than 0.05 for DBP). The reduction in systolic blood pressure was significantly correlated with the reduction in body weight induced by treatment (r = 0.63, P less than 0.02). No consistent changes in glucose or lipid metabolism were induced by treatment.
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PMID:Plasma ionized calcium and cardiovascular risk factors in mild primary hyperparathyroidism: effects of long-term treatment with active vitamin D (alphacalcidol). 158 70

Cloned rat parathyroid cells (PTr cell line) that produce parathyroid hormone-related peptide plus endothelin 1 and primary cultures of human parathyroid cells were tested for growth and differentiation responses to atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). High- and low-affinity binding sites for ANP were found on PTr cells; BNP appeared to bind to the same receptors with similar affinities. Either ANP or BNP stimulated production of cGMP and caused a 30% decrease in Na(+)-K(+)-Cl- cotransport. Each peptide increased synthesis and secretion of endothelin 1 by PTr cells in a dose-dependent fashion, but cell growth was not affected. Human parathyroid cells (normal and pathological) also responded to ANP or BNP with an increase in cGMP production. The finding of receptors for natriuretic hormones on parathyroid cells with consequent effects on release of endothelin 1 might be of relevance in understanding the clinical association between hyperparathyroidism and hypertension.
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PMID:Natriuretic peptide receptors regulate endothelin synthesis and release from parathyroid cells. 165 Apr 71

Hypertension in primary hyperparathyroidism (HPT) was previously attributed to hypercalcemia per se or to impaired kidney function. Of 441 consecutive patients operated on for HPT over 24 years, 57% were hypertensive. Preoperative blood pressure remained fairly constant during the study period, despite otherwise markedly changing clinical picture with, latterly, more asymptomatic patients. The preoperative systolic blood pressure (SBP) was significantly correlated to both serum calcium (p less than 0.001) and serum creatinine (p less than 0.05), but not when the influence of age was taken into account in a multiple regression analysis. Other pathogenetic factors in hypertension were therefore probable. When the statistical analysis was adjusted for differences in age and serum calcium, blood pressure was lower in the HPT patients with parathyroid hyperplasia than in those with adenoma (153 +/- 31/90 +/- 14 vs. 163 +/- 29/91 +/- 14 mmHg, p less than 0.01 for SBP). The concept that parathyroid hyperplasia represents a mild (early) form of HPT that may precede adenoma formation is corroborated by our observations, which also indicate that there is no simple cause-and-effect relationship accounting for hypertension in primary HPT.
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PMID:Hypertension in primary hyperparathyroidism in relation to histopathology. 168 31


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