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)

The in vitro effect of parathyroid hormone (PTH) on RNA and heme synthesis by embryonic mouse liver erythroid precursors was examined. PTH produced a dose-dependent effect on RNA synthesis. A maximal increase of 60 +/- 16% (p less than 0.02) was observed with 1.0 U PTH/ml, whereas with higher concentrations a significant decline was found. Furthermore, PTH stimulated heme synthesis after 24 h of incubation. The maximal enhancement of 32 +/- 7% (p less than 0.01) was observed with 0.5 U PTH/ml, a lower effect was obtained with 1.0 U PTH/ml, while 2.0 U PTH/ml caused a pronounced decrease of heme synthesis. These data indicate that PTH affects directly the erythroid precursors by a mechanism similar to that of erythropoietin. The inhibitory effect on the RNA synthesis observed with large doses of PTH may explain at least one of the causes of the anemia reported in patients with primary hyperparathyroidism.
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PMID:Increased RNA and heme synthesis in mouse erythroid precursors by parathyroid hormone. 10 88

Primary as well as secondary hyperparathyroidism may be associated with anemia, and parathyroidectomy (PTx) may improve or even heal it. The precise link between the two conditions is still matter of discussion. The purpose of the present study was to investigate possible effects of PTx on serum immunoreactive erythropoietin (iEPO) in secondary (group I, n = 23), and primary (group II, n = 16) hyperparathyroidism patients, and in 3 patients undergoing cervicotomy for thyroid mass removal (group III). In group I patients, circulating iEPO levels rose from 23.1 +/- 4.8 mU/ml before PTx to 28.2 +/- 5.0 and 245 +/- 125 mU/ml (mean +/- SEM) at day 7 (p = NS) and 14 after PTx (p less than 0.003), respectively. Reticulocyte count increased 2 weeks after PTx: from 61,000 +/- 13,317 to 86,533 +/- 13,462/mm3 (p less than 0.05, n = 23). In 4 of these patients serum iEPO levels could be measured again 12-24 months after PTx. They were slightly higher than those determined before PTx: 37.0 +/- 8.4 versus 31.8 +/- 13.5 mU/ml. Their hematocrits were also higher than before PTx: 12.8 +/- 0.9 versus 11.0 +/- 0.9 g/dl. In group II patients, serum iEPO levels remained unchanged after PTx: 17.5 +/- 2.0 mU/ml before PTx and 20.0 +/- 3.0 mU/ml 14 days PTx. The reticulocyte count, however, increased significantly 2 weeks after PTx: from 25,103 +/- 3,000 to 40,827 +/- 4,080/mm3 (p less than 0.01). In group III patients, serum iEPO, reticulocyte count, and hemoglobin remained stable after surgery. Since all group I patients had received vitamin D supplementation after PTx, we studied an additional group of 14 chronic dialysis patients (group IV) who received either calcitriol (1 micrograms/day, n = 7) or placebo (n = 7) during 14 days. The patients on calcitriol treatment, but not those on placebo, had a significant decrease of serum iEPO: 18.6 +/- 4.9 versus 16.0 +/- 4.2 mU/ml (p less than 0.03). In conclusion, PTx led to a striking increase of serum iEPO and blood reticulocytes in uremic patients with secondary hyperparathyroidism, and an increase of reticulocyte count, but not of iEPO, in patients with primary hyperparathyroidism. Marked changes of circulating PTH, extra-or intracellular calcium and phosphorus concentrations as well as of tissue sensitivity to EPO after PTx could all be responsible. In contrast, the surgical procedure and the therapeutic increase in plasma calcitriol do not appear to be involved.
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PMID:Serum erythropoietin and erythropoiesis in primary and secondary hyperparathyroidism: effect of parathyroidectomy. 175 26

It is suggested that parathyroid hormone (PTH), when in excessive amounts, interferes with normal erythropoiesis by downregulating the erythropoietin receptors on erythroid progenitor cells in the bone marrow. Therefore, physiologic concentrations of EPO can no longer sustain normal red cell counts, so normocytic and normochromic anaemia ensues. In primary hyperparathyroidism (HPT), this effect is observed with very high concentrations of PTH. In secondary HPT during chronic renal failure, this effect is more pronounced because erythropoietin synthesis is impaired.
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PMID:Pathogenesis of anaemia in hyperparathyroidism. 1079 Jul 58