Disease relevance of Parathyroid Glands

• DiGeorge syndrome (DGS), a developmental defect, is characterized by cardiac defects and aplasia or hypoplasia of the thymus and parathyroid glands [1].
• Because neonatal bovine and pathological human parathyroid glands show cellular hyperplasia, we studied the temporal relationship between cellular proliferation and the regulation of PTH release and cytosolic calcium concentration in cultured bovine parathyroid cells [2].
• Most of the remaining 61 cases had proven or probable typical primary hyperparathyroidism, and a subgroup of four had hypercalcemia with suppression of the parathyroid glands [3].
• None of the eight hyperplastic lesions, three cases of parathyromatosis, ten parathyroid adenomas, eleven carcinomas or one normal parathyroid gland contained mutations in each of the three RET exons tested [4].
• Cows fed a balanced diet with the required amounts of calcium and phosphorus developed acute hypocalcemia and hypophosphatemia shortly after parturition, even in the presence of the a responsive parathyroid gland, when bone resorption was selectively inhibited by the prepartal administration of disodium ethane-1-hydroxy-1, 1-diphosphonate (EHDP) [5].

Psychiatry related information on Parathyroid Glands

• CONCLUSIONS: The intraoperative iPTH assay in patients operated on for secondary hyperparathyroidism offers support in surgical decision making in the majority of patients, allowing for correct identification of patients with supranumerary ectopic hyperfunctioning parathyroid glands, and in patients with fewer than four parathyroid glands [6].

High impact information on Parathyroid Glands

• A good example of a new function described for 1alpha,25-dihydroxyvitamin D3 is that found in the parathyroid gland [7].
• Glial cells missing2 (Gcm2), a mouse homologue of Drosophila Gcm, is the only transcription factor whose expression is restricted to the parathyroid glands [8].
• Genetic ablation of parathyroid glands reveals another source of parathyroid hormone [8].
• Addition of cortisol (10(-6) to 10(-8) M) and related glucocorticoid congeners to cultures of rat parathyroid glands stimulated dose-related increases in parathyroid hormone secretion; the addition of deoxycorticosterone or cortexolone was without effect [9].
• Thus, our results indicate a likely new role for SOX3 in the embryonic development of the parathyroid glands [10].

Chemical compound and disease context of Parathyroid Glands

• In summary, in the 11-week-old SHR we observed reduced circulating calcitriol levels together with increased tissue calcitriol receptor numbers, increased parathyroid gland mass, and histological evidence of hyperparathyroidism [11].
• In the present study, we examined the effects of hyperparathyroidism and dietary calcium and 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] on the expression of VDR in rat parathyroid glands [12].
• The enhancement in parathyroid gland weight and proliferating activity (proliferating cell nuclear antigen/Ki67) induced by kidney disease and aggravated by either high P or low Ca intake, within the first week after 5/6 nephrectomy, in rats, coincided with simultaneous increases (2- to 3-fold) in TGF-alpha and EGFR content [13].
• The ability of the parathyroid glands to synthesize and secrete parathyroid hormone in response to hypocalcemia induced either by EDTA or associated with parturition was not impaired by the administration of EHDP [14].
• Methylene blue administered intravenously in a dose of 5 mg/kg of body weight was employed as an aid to the intraoperative identification of parathyroid glands in 90 patients undergoing surgery for hyperparathyroidism [15].

Biological context of Parathyroid Glands

• However, since the parathyroid glands possess specific receptors for 1,25(OH)2D3 and a calcium binding protein, there is considerable interest in a possible direct effect of 1,25(OH)2D3 on parathyroid hormone (PTH) secretion independent of changes in serum calcium [16].
• It is suggested that the inhibition of platelet aggregation by extracts of bovine parathyroid glands is not caused by PTH fragments and is probably an effect of other constituents contained in the extract [17].
• The aim of the study was to evaluate in vitro the effect of calcitriol on parathyroid cell proliferation and apoptosis in normal parathyroid glands and in adenomatous and hyperplastic human parathyroid glands [18].
• To determine if parathyroid hormone (PTH) is essential for lactation in rats, the parathyroid glands were removed surgically during the first week of lactation and the rats were given a diet containing a high calcium-phosphorus ratio to maintain a normal serum calcium concentration [19].
• Tissue and gene specific hypomethylation of the human parathyroid hormone gene: association with parathyroid hormone gene expression in parathyroid glands [20].

Anatomical context of Parathyroid Glands

• Developmentally, the parathyroid gland is derived from the pharyngeal pouch endoderm, and studies in mice have shown that its formation is under the control of a key regulatory gene, Gcm-2 [21].
• There were no obvious abnormalities in the caudal pharyngeal pouch derivatives (the thymus, parathyroid glands, and thyroid gland), heart, and gut [22].
• Chief cells within bovine parathyroid glands exhibit a similar pattern of staining for caveolin-1 and for alkaline phosphatase, a glucosylphosphatidylinositol-anchored protein often enriched in caveolae [23].
• Secretogranin II message was absent from parathyroid gland, adrenal cortex, kidney, liver, and spleen [24].
• A survey of human and mouse tissues analysed with polyclonal antibodies to parafibromin showed specific immunoreactivity in adrenal and parathyroid glands, kidney, heart, and skeletal muscle [25].

Associations of Parathyroid Glands with chemical compounds

• This direct stimulatory effect of cortisol on parathyroid gland secretion may account in part for the increased concentration of parathyroid hormone in the serum of cortisol-treated animals [9].
• Plasma cyclic AMP was elevated from 23 nM in control subjects to 59 nM in uremic patients, regardless of the presence or absence of the kidneys or parathyroid glands [26].
• Preoperative imaging of parathyroid glands with technetium-99m-labelled sestamibi and iodine-123 subtraction scanning in secondary hyperparathyroidism [27].
• The discovery of unique 1alpha,25-(OH)2D3-binding components in the parathyroid glands is consistent with the sterol hormone's action at this endocrin site and possible involvement in the regulation of parathyroid hormone synthesis and secretion [28].
• In a study on experimental animals, the results clearly showed that this first generation of calcimimetics, NPS R-568, had an acute dose-dependent and short-lived suppressive effect on PTH secretion from the parathyroid glands [29].

Gene context of Parathyroid Glands

• Despite their lack of parathyroid glands, Gcm2-deficient mice have PTH serum levels identical to those of wild-type mice, as do parathyroidectomized wild-type animals [8].
• Primary hyperparathyroidism is a common endocrine disorder caused by parathyroid gland enlargement and excessive parathyroid hormone (PTH) secretion [30].
• Here, we show that loss of Men1 gene function in the parathyroid glands of mice results in histological changes consistent with parathyroid neoplasia as well as systemic hypercalcemia [31].
• Histological and immunohistochemical examination revealed that the resected parathyroid glands showed lipohyperplasia as well as normally expressed Ki67, vitamin D receptor (VDR), and the CaR [32].
• Parathyroid gland VDRmRNA and VDR protein were increased in hypercalcemic rats as compared with hypocalcemic rats [33].

Analytical, diagnostic and therapeutic context of Parathyroid Glands

• Staining of frozen sections of small parathyroid biopsies from patients with primary hyperparathyroidism with Sudan II or IV revealed the almost uniform presence of numerous prominent intracellular sudanophilic bodies in the chief cells of suppressed "normal" parathyroid glands [34].
• Calcitonin deficiency was produced in lactating and age-matched nonmated rats by thyroidectomy (TX) after transplantation of the parathyroid glands to a thigh muscle [35].
• PTH fragments of varying length arise either from metabolism of the intact hormone within the parathyroid glands or in peripheral tissues, such as liver, and the resulting carboxyl-terminal peptides are eliminated mainly by glomerular filtration and subsequent tubular degradation [36].
• In this paper we present the results of a morphometrical study of ten normal parathyroid glands from patients undergoing thyroidectomy, 20 enlarged 'adenomatous' glands from patients with primary hyperparathyroidism, and 20 glands of normal size from the same hyperparathyroid patients [37].
• Total poly(A+) RNA was prepared by phenol-chloroform-isoamyl alcohol extraction and oligo-dT-cellulose affinity chromatography from the tumor tissue and bovine parathyroid glands [38].

References