calcimycin and Hyperparathyroidism

Synthesis of leukotriene B4 (LTB4) upon stimulation of peripheral blood samples with the calcium ionophore A 23187 was studied in patients with primary hyperparathyroidism who underwent parathyroidectomy. Preoperatively, an increased LTB4 concentration of 1.76 +/- 0.19 ng/ml plasma was found, vs. 0.95 +/- 0.28 ng/ml in healthy individuals. On the fourth day after operation, the LTB4 concentration was almost normalized, reaching 1.25 +/- 0.23 ng/ml plasma. At the same time, mean serum calcium levels were reduced from 6.1 +/- 0.6 meq/liter before operation to 4.53 +/- 0.28 meq/liter after operation. In a control group, euthyroid patients with thyroid adenomas who underwent adenomectomy had normal LTB4 levels before operation (0.84 +/- 0.11 ng/ml) and did not show significant changes in LTB4-synthesizing capacity. The results indicate that synthesis of LTB4 in vivo may depend in part on factors related to serum calcium concentration or calcium metabolism.

Topics: Adenoma; Calcimycin; Calcium; Humans; Hyperparathyroidism; Leukotriene B4; Neutrophils; Parathyroid Glands; Thyroid Neoplasms

The effects of the Ca2+ ionophore A23187 on parathyroid hormone (PTH) secretion and cytoplasmic free Ca2+ concentration (Ca2+i) were measured at different extracellular Ca2+ concentrations using dispersed cells from patients with hyperparathyroidism (HPT). The addition of a low concentration of the Ca2+ ionophore to quin2-loaded cell preparations resulted in the apparent normalization of calcium-regulated Ca2+i. At all extracellular calcium concentrations Ca2+i reached significantly higher values in the presence of the ionophore and the dose-response relationship was shifted to the left. Under similar conditions calcium-regulated PTH release was correspondingly corrected with an increased suppressibility and left-shifted dose-response relationship. The data render strong support for a disturbed regulation of Ca2+i as a major factor in the pathophysiology of HPT.

Topics: Aminoquinolines; Calcimycin; Calcium; Fluorescent Dyes; Humans; Hyperparathyroidism; Parathyroid Glands; Parathyroid Hormone; Spectrometry, Fluorescence

Topics: Calcimycin; Calcium; Cells, Cultured; Cyclic AMP; Humans; Hyperparathyroidism; In Vitro Techniques; Isoproterenol; Parathyroid Glands; Parathyroid Hormone

To examine whether alterations in parathyroid adenylate cyclase might be associated with glandular hyperfunction, we compared enzyme activity in membranes from 7 normal glands with activity from 18 abnormal and 5 noninvolved glands from patients with primary hyperparathyroidism. Compared with the normal glands, the specific enzyme activity after full stimulation with guanyl-5'yl imidodiphosphate was significantly decreased in both hyperplastic and noninvolved glands from the hyperparathyroid subjects. While the enzyme activity of all tissues could be suppressed by calcium, a twofold higher calcium concentration was required for comparable suppression of the enzyme from adenomas as compared with normal or noninvolved glands. Alterations in the adenylate cyclase complex of hyperplastic parathyroid glands may explain, in part, the elevated "set point" for calcium homeostasis in primary hyperparathyroidism.

Topics: Adenoma; Adenylyl Cyclase Inhibitors; Adenylyl Cyclases; Adult; Aged; Calcimycin; Calcium; Child; Dose-Response Relationship, Drug; Female; Guanylyl Imidodiphosphate; Humans; Hyperparathyroidism; In Vitro Techniques; Male; Middle Aged; Parathyroid Glands; Parathyroid Neoplasms