Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0221002 (primary hyperparathyroidism)
 4,921 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary hyperparathyroidism (PHPT) is characterized by hypersecretion of parathyroid hormone (PTH) leading to hypercalcemia and relative hypophosphatemia. PTH acts by binding to cell surface receptors coupled to G proteins. Cyclic AMP is the classic second messenger of PTH action, but substantial evidence indicates that PTH also acts to stimulate formation of the dual second messengers, inositol trisphosphate and diacylglycerol, thereby mobilizing intracellular calcium. The physiologic actions of PTH include (1) an increase in extracellular fluid ionized calcium through direct actions on kidney and bone, the classic target organs for PTH, and (2) a decrease in extracellular fluid phosphate primarily through renal action. The pathophysiologic effects of PTH arise from (1) direct actions of PTH on bone and kidney, and possibly on nonclassic target organs, and (2) indirect effects of altered mineral homeostasis. PTH hypersecretion in PHPT can lead to bony demineralization, nephrolithiasis, and hypercalcemic crisis. PHPT may also be associated with mental disturbances, neuromuscular disease, hypertension, and glucose intolerance.
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PMID:Pathophysiology of primary hyperparathyroidism. 176 67

The need for treatment of mild and apparently asymptomatic primary hyperparathyroidism (HPT) is questioned, but a raised incidence of cardiovascular disease has been regarded as evidence in favour of surgery. While it is well known that several risk factors for cardiovascular disease (hypertension, hyperlipidaemia and diabetes mellitus/impaired glucose tolerance) are overrepresented in HPT, it is not known whether surgery provides long-term normalization in these respects and reduces the risk of premature death. In a 15-year follow-up of a cohort of 172 subjects in whom mild hypercalcaemia was initially detected during a health screening, it was found that 56 subjects had died. 17 individuals had been operated on for HPT, 47 individuals were persistently hypercalcaemic, while 45 subjects had serum calcium within the normal range (seven individuals were lost to follow-up). There had been no significant differences in blood pressure between these groups of mildly hypercalcaemic patients and age- and sex-matched controls at the initial screening, but at follow-up blood pressure was significantly higher not only in subjects with persistent hypercalcaemia, but also in those who had been successfully operated on for HPT. Neither of the hypercalcaemic groups showed any significant deviations from the controls with regard to indices of lipid or glucose metabolism. These findings suggest that there is no simple cause-and-effect relationship to account for the propensity toward high blood pressure in primary HPT. Consequently it cannot be assumed that surgery for HPT will eliminate the increased risk of cardiovascular disease in patients with mild HPT.
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PMID:Cardiovascular risk factors in primary hyperparathyroidism: a 15-year follow-up of operated and unoperated cases. 206 9

The aim of the present study was to determine the diurnal secretion of melatonin, cortisol, prolactin, and calcitonin during chronic parathyroid hormone-dependent hypercalcemia. Eight women, aged 40-76 years, with primary hyperparathyroidism (PHPT) were studied before and after surgical removal of a parathyroid adenoma. The hormone concentrations in blood were determined at 08, 12, 16, 22, 02, 04, and 06 h. Concomitantly, the excretion of melatonin and cortisol in urine between 07-19 h and 19-07 h, and the clearance of calcium and creatinine were measured. Nyctohemeral serum prolactin and calcitonin were unaffected by moderate parathyroid hormone-dependent hypercalcemia. In contrast, serum cortisol and melatonin were significantly higher during active disease than after surgical cure. Mean 24-h variation of serum cortisol was 349 +/- 34 nmol/liter vs. 223 +/- 17 nmol/liter and mean serum melatonin was 0.13 +/- 0.04 nmol/liter vs. 0.06 +/- 0.02 nmol/liter. Endogenous creatinine clearance was similar before and after surgery, while the clearance of melatonin and cortisol significantly increased after surgery, indicating an increased tubular reabsorption of both hormones during active disease. Fasting morning glucose concentrations were also significantly decreased after successful surgery, 6.1 +/- 0.6 vs. 5.2 +/- 0.5 mmol/liter. It is suggested that the relative hypercortisolism may be the cause of the glucose intolerance in primary hyperparathyroidism. Three to 4 months after surgical cure the serum melatonin levels were significantly lower than those seen in age-matched controls, indicating a melatonin insufficiency in patients successfully treated for PHPT. The meaning of this finding is not yet understood but might be of importance in the development of primary hyperparathyroidism.
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PMID:Melatonin, cortisol, prolactin, and calcitonin secretion in primary hyperparathyroidism before and after surgery. 362 59

Carbohydrate metabolism was investigated in 9 patients with symptomatic primary hyperparathyroidism. Before and after parathyroidectomy intravenous and oral glucose tolerance test, tolbutamide test, arginine infusion test and insulin tolerance test were performed. During intravenous and oral glucose tolerance tests, patients with primary hyperparathyroidism exhibited hyperinsulinemia and impaired glucose tolerance without normalization after surgery. Tolbutamide-induced induced insulin release did not differ pre- or postoperatively. After restoration of normocalcemia and normocalcemia and normophosphatemia we found significantly lower glucose and insulin levels following arginine infusion and a significantly increased hypoglycemic response to parenterally administered insulin, probably indicating partial improvement of glucose tolerance after surgery. Our findings suggest that biochemical abnormalities associated with primary hyperparathyroidism, like hypercalcemia, hypophosphatemia, and elevated parathyroid hormone levels may cause and sustain a form of endogenous insulin resistance, which consequently leads to hyperinsulinemia and to impaired glucose tolerance. Since hyperinsulinemia as well as impaired glucose tolerance seem to be only slowly and partially reversible in symptomatic primary hyperparathyroidism, these data could be considered as an additional argument for early surgical intervention in this disorder.
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PMID:Peripheral insulin resistance in primary hyperparathyroidism. 634 5

It is generally known that patients with primary hyperparathyroidism (pHPT) feature disturbances in carbohydrate metabolism and hypertension. The incidence and prevalence of frank diabetes mellitus is significantly increased in these patients. The etiology and pathogenesis of the vascular and metabolic aberrations in this condition are still unclear. Glucose intolerance in pHPT is characterized by severe insulin resistance associated with pancreatic beta cell hypersecretion of insulin. Hypercalcemia is thought to be mainly responsible for the impaired glucose metabolism. However, several studies demonstrated that hypophosphatemia can also induce insulin hypersecretion and impair peripheral glucose uptake. Hypertension in primary hyperparathyroidism is mainly attributed to hypercalcemia. However, high peripheral insulin levels are also proposed to contribute to the development of essential hypertension and hyperinsulinemia per se is regarded as an important independent cardiovascular risk factor. After parathyroidectomy and decrease of the calcium levels to within the normal range, the blood pressure levels of the patients with pHPT normalised very quickly, whereas normalization of the high peripheral insulin levels was only found in a subgroup of patients. Thus, hypercalcemia seems to be mainly responsible for hypertension in primary hyperparathyroidism. Another important, yet unresolved issue is the question as to whether or to which extent the disturbances in glucose homeostasis are reversible after surgical correction of pHPT. At an early stage of the disease, insulin resistance and insulin hypersecretion are fully reversible after parathyroidectomy, whereas in patients with long-standing primary hyperparathyroidism and severely impaired glucose tolerance the metabolic disturbances will only partially improve. These results argue for improved screening to identify asymptomatic patients with primary hyperparathyroidism and for early surgical intervention in this disease.
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PMID:[Diabetes mellitus and carbohydrate metabolism in primary hyperparathyroidism]. 847 26

Amylin, also named islet amyloid polypeptide (IAPP), is a protein that is processed and released from pancreatic beta-cells in parallel with insulin. Islet amyloid polypeptide is currently studied with regard to a role for insulin resistance in non-insulin-dependent diabetes. To elucidate a possible function of IAPP for impaired glucose tolerance in primary hyperparathyroidism (pHPT), we studied plasma IAPP levels during an oral glucose tolerance test (OGTT) in seven pHPT patients before and 8 weeks after surgery and in six healthy subjects. The B-glucose level of the patient groups was 4.34 +/- 0.12 mmol/l before and 3.97 +/- 0.16 mmol/l after surgery (NS), while the serum level of insulin was significantly higher before (16.9 +/- 2.8 mlU/l) than after (8.9 +/- 1.9 mlU/l) the operation (p < 0.05), indicating a moderately increased insulin resistance in pHPT. The basal plasma levels of IAPP were significantly higher in pHPT patients before than 8 weeks after surgery (9.71 +/- 1.05 and 4.30 +/- 0.82 pmol/l, respectively: p < 0.01). When compared to the plasma IAPP level of the controls at 1.80 +/- 0.38 pmol/l, pHPT patients had higher IAPP values both before (p < 0.01) and at 8 weeks after (p < 0.05) operation. There was a significant correlation between the serum levels of insulin and plasma levels of IAPP in pHPT patients before (r = 0.87, p < 0.01) as well as 8 weeks after surgery (r = 0.69, p < 0.05). The area under the curve for IAPP during OGTT in pHPT patients was 1872.4 +/- 187.7 pmol.min/l, which is significantly higher than after surgery (1010.8 +/- 93.7 pmol.min/l) (p<0.05) and compared to the area for the controls at 840.3 +/- 49.9 pmol.min/l (p<0.01). In conclusion, pHPT is associated with an increased plasma level of IAPP, correlated to the serum insulin level, but persistently higher than in controls also 8 weeks after surgery. Possibly, increased IAPP levels can have a role for impaired glucose tolerance in pHPT. The hyperparathyroid state might have a specific role for the release of this peptide, otherwise closely connected to insulin secretion
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PMID:Increased plasma levels of islet amyloid polypeptide in patients with primary hyperparathyroidism. 861 29

The prevalence of diabetes mellitus in primary hyperparathyroidism is approximately 8% and that of primary hyperparathyroidism in diabetic patients is approximately 1%. Both values are about three-fold higher than the respective expected prevalences in general populations. Patients with both disorders are over 40 years of age and 80% are female; 22% have type 1 and 78% type 2 diabetes. Primary hyperparathyroidism presents first in approximately 20% of patients, and diabetes mellitus in 40%; both disorders present together, or within 1 year, in 40%. Approximately 40% of patients with primary hyperparathyroidism have impaired glucose tolerance. Insulin resistance is present in hyperparathyroidism and probably arises from a raised intracellular free calcium concentration which, by decreasing normal insulin-stimulated glucose transport, increases the requirement for insulin: if this insulin resistance progresses, impaired glucose tolerance and diabetes mellitus would result. Parathyroidectomy has been followed by regression of diabetes and of impaired glucose tolerance in some but not all patients. Early diagnosis of the second disorder is clinically desirable when one disorder is present. Hyperparathyroid patients should therefore be screened for impaired glucose tolerance and diabetes annually, and pre-operatively. Diabetic patients should be checked for hypercalcaemia at appropriate intervals; although only 1% of them may have hyperparathyroidism, this disorder if untreated is associated with hypertension, to which diabetic patients are already prone.
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PMID:Coincident diabetes mellitus and primary hyperparathyroidism. 1142 30

Diabetes mellitus is associated with various organ dysfunctions through hyperglycemia, insulin deficiency, or advanced glycation end products, which can also cause impaired calcium homeostasis such as the reductions of parathyroid hormone secretion, vitamin D receptor (VDR) number, and 25- (OH) vitamin D-1 alpha-hydroxylase activity in the parathyroid gland, intestine, and kidney, respectively. On the contrary, abnormal calcium homeostasis such as vitamin D deficiency/insensitivity and hyperparathyroidism can cause glucose intolerance or diabetes. Vitamin D deficiency/insensitivity induces type 2 diabetes through impaired insulin secretion involving VDR on pancreatic beta cells, as well as type 1 diabetes through the reduction in immuno-modulatory action of 1,25 (OH)(2) vitamin D. Primary hyperparathyroidism induces glucose intolerance via insulin resistance due to elevated intracellular calcium in the targeted organ of insulin.
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PMID:[Calcium homeostasis and diabetes mellitus]. 1688 34

Long-term follow-up is initially considered appropriate for the majority of patients with primary hyperparathyroidism (PHPT) having small increases in calcium levels (< 2.8 mmol/l) and lacking the 'classical' symptoms of PHPT. The supportive reasoning is that many such patients never progress to more severe biochemical or clinical disease. There are, however, arguments in favour of early surgical treatment of such patients but adequately powered studies have not been carried out in this subgroup of patients to asses the impact of PHPT on their quality of life, cardiovascular risk and bone density. Progressive loss in bone mineral density and an increased risk of bone fracture become increasingly significant in an ageing population. Left ventricular hypertrophy, an increased risk of arrhythmia and/or myocardial infarction in addition to changes in atherogenic lipid profile and impaired glucose tolerance may translate into an increased risk of premature death in this group of patients. Changes in the quality of life identified using standardized questionnaires are sometimes recognized by patients only in retrospect (i.e. after resolution of symptoms following successful parathyroidectomy). In addition, many series fail to assess and record accurately such symptoms. Multicentre cohort studies of patients with asymptomatic PHPT randomized to immediate or delayed surgical treatment could address some of the debated issues highlighted in this review. Until such studies are set up, most surgeons would consider that parathyroid surgery should represent the first choice of treatment for all patients, but many physicians would favour a long-term follow-up. Nevertheless, the threshold for referral for surgical treatment has been lowered since the introduction of scan-directed minimally invasive parathyroidectomy, which enables the experienced parathyroid surgeon to successfully treat patients with PHPT with a minimum of complications as a day-case operation. In the context of improved surgical treatment, we need more data on the benefits or otherwise in so-called asymptomatic patients with a thorough assessment of their bone quality, cardiovascular risk and quality of life.
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PMID:Asymptomatic hyperparathyroidism--need for multicentre studies. 1765 48

Osteocalcin (OC) has been proposed as a regulator of insulin sensitivity in both humans and other animals. Primary hyperparathyroidism (PHPT) is characterized by high OC levels and insulin resistance. The aim of this study was to evaluate whether in PHPT the link between OC levels and blood markers of insulin resistance was maintained. In a consecutive series of 219 adult PHPT patients, serum OC as well as fasting insulin and glucose levels were measured. Insulin sensitivity was estimated by homeostatic model assessment (HOMA2-S%). The same parameters were evaluated in a subgroup of 45 patients after parathyroidectomy (PTX). PHPT patients were characterized by markedly high OC levels. After subdividing them according to glucose tolerance, it was found that OC was similar in subjects with normal glucose tolerance (NGT) and impaired glucose tolerance (IGT), while diabetic subjects had lower serum OC than those with NGT (P < 0.02) or IGT (P < 0.04). OC was negatively associated with fasting glucose and positively associated with HOMA2-S%. OC independently predicted HOMA2-S% in a multivariate analysis. In the subgroup of surgically cured PHPT patients, OC levels significantly decreased after PTX, while HOMA2-S% did not change. Our findings indicate that in PHPT there is a positive relationship between OC and glucose metabolism, OC being one of the predictors of insulin sensitivity. However, data in surgically cured patients, showing OC normalization in spite of unchanged HOMA2-S%, suggest that OC does not likely play a major role in affecting insulin sensitivity in PHPT.
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PMID:Interplay between serum osteocalcin and insulin sensitivity in primary hyperparathyroidism. 2120 16


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