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 effects of lithium on calcium-regulated parathyroid hormone (PTH) release were assessed in collagenase-dispersed bovine parathyroid cells. Preincubation for 4 hours with LiCl caused a dose-dependent increase in the concentration of calcium required for half-maximal inhibition of immunoreactive PTH release (the "set-point" for calcium). A significant increase in "set-point" was observed following exposure to 1.25 mM lithium, a concentration within the therapeutic range for man. This effect required preincubation with LiCl, was not seen with NaCl or KCl, and persisted despite removal of extracellular lithium. This lithium-induced abnormality in calcium-regulated PTH secretion may be a useful model system for analyzing the analogous defect in secretory control in primary hyperparathyroidism.
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PMID:Lithium induces abnormal calcium-regulated PTH release in dispersed bovine parathyroid cells. 722 89

In Paget's disease of bone, the normal lamellar bone is replaced by a woven structure with an irregular arrangement of collagen fibers. In this study, we investigated whether the degree of beta-isomerization within C-telopeptide of alpha 1 chain of type I collagen was altered in Paget's disease compared with other bone diseases with no alteration of bone structure. In Paget's disease (n = 26), but not in patients with primary hyperparathyroidism (n = 6) or hyperthyroidism (n = 17), the urinary excretion of nonisomerized (alpha) fragments derived from degradation of type I collagen C-telopeptide (CTX) was markedly increased compared with beta-isomerized CTX (+ 13-fold vs. + 3.5-fold over controls) resulting in an urinary alpha CTX/beta CTX ratio 3-fold higher than in controls (2.6 +/- 1.0 vs. 0.8 +/- 0.3, p < 0.001). In five pagetic patients in complete remission, as demonstrated by normal total alkaline phosphatase activity, the alpha CTX/beta CTX ratio was normal. The immunohistochemistry of normal and pagetic human bone sections showed a preferential distribution of alpha CTX within woven structure, while lamellar bone was intensely stained with an anti-beta CTX antibody, suggesting a lower degree of beta-isomerization of type I collagen in the woven pagetic bone. In collagenase digest of human bone specimens, we found a lower proportion of beta-isomerized type I collagen molecules in pagetic bone (40% of beta CTX) than in normal bone taken from trabecular (68%) and cortical compartments (71%). In conclusion, we found that in Paget's disease the alpha CTX/beta CTX ratio in bone and in urine is markedly increased. This altered beta isomerization can be accurately detected in vivo by measuring urinary degradation products arising from bone resorption.
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PMID:Decreased beta-isomerization of the C-terminal telopeptide of type I collagen alpha 1 chain in Paget's disease of bone. 928 56