Expression of parathyroid hypertensive factor in hypertensive primary hyperparathyroid patients

Effect of successful parathyroidectomy on 24-hour ambulatory blood pressure in patients with primary hyperparathyroidism

OBJECTIVE

The pathogenesis of hypertension in patients with primary hyperparathyroidism (PHPT) is unclear, and the prevailing opinion is that parathyroidectomy does not affect the blood pressure (BP). Most previous studies have been based on BP measurements at rest in a clinical setting. The aim of this study was to get additional information by 24-hour ambulatory measurements.

DESIGN AND PATIENTS

Forty-nine consecutive patients with PHPT (age 63+/-12 years, 44 women) were examined before and 6 months after curative parathyroid surgery.

MEASUREMENTS

Serum concentrations of calcium and PTH, and 24-hour ambulatory mean, minimum, and maximum systolic (S) and diastolic BP, and mean arterial BP.

RESULTS

On average, the patients showed no BP change after parathyroidectomy. However, those with a history of hypertension (n=20) showed generally increased BP values after parathyroidectomy, with significantly increased minimum and average SBP (P=0.02 and P=0.04, respectively), whereas patients without a history of hypertension (n=29) showed unchanged or slightly reduced BP values after parathyroidectomy, with significantly decreased maximum SBP (P=0.04). Serum concentrations of PTH and calcium were not significantly related to any of the BP variables measured.

CONCLUSIONS

The novel finding that patients with both PHPT and hypertension may show increased BP after parathyroidectomy warrants intensified BP control postoperatively in these patients, and motivates early treatment of PHPT in order to prevent the development of complicating hypertension.

Isolation and characterization of coenzyme A glutathione disulfide as a parathyroid-derived vasoconstrictive factor

BACKGROUND

Coenzyme A glutathione disulfide (CoA-SSG) was recently isolated from bovine adrenal glands and was shown to be a renal vasoconstrictor. The identification of CoA-SSG in human parathyroid glands and its action on cultured vascular smooth muscle cells (VSMCs) are described here.

METHODS AND RESULTS

After purification to homogeneity by several chromatographic steps, CoA-SSG was identified by matrix-assisted laser desorption/ionization mass spectrometry and enzymatic analysis. The dose-dependent growth-stimulating effect of CoA-SSG on VSMCs, measured by the [(3)H]thymidine method, is characterized by a threshold of 10(-)(8) mol/L and a maximum effect of 10 micromol/L, increasing VSMC proliferation 254+/-21% above control. A dose of 10 micromol/L methylmalonyl-CoA and 10 micromol/L CoA increased the rate of proliferation of VSMCs only by 178+/-43% and 50+/-42% above control, respectively. Glutathione has no proliferative effect on VSMCs. The growth-stimulating effect of CoA-SSG (1 micromol/L) was decreased by the antagonists 3,7-dimethyl-1-propargylxanthine (DMPX; 11 micromol/L) (38% compared with CoA-SSG without antagonist) and pyridoxal-phosphate-6-azophenyl-2,4-disulfonic acid (PPADS; 10 micromol/L) (48% compared with CoA-SSG without antagonist; each P:<0. 05 versus control), indicating that the effect is mediated partly via A(2) and partly via P(2)Y(1) and/or P(2)Y(4) receptor.

CONCLUSIONS

CoA-SSG may play a regulatory role in VSMC growth as a progression factor and thereby could play an important role in development of hypertension.