Endothelin-1 is involved in the transient hypoparathyroidism seen in patients undergoing thyroid surgery

We have studied the serial changes in plasma endothelin (ET)-1, serum parathyroid hormone (PTH) and serum calcium concentrations during surgery in 20 patients undergoing a hemithyroidectomy for thyroid carcinoma. The plasma ET-1 concentrations increased within the first 24 h following surgery in 18 out of 20 cases with the peak concentration achieved between 1 and 12 h. Gel permeation chromatography showed only one major peak at the elution position of human ET-1 standard both in the pre- and postoperative plasma. Thirteen patients showed transient hypoPTHaemia and hypocalcaemia which clearly coincided with the peak plasma ET-1 concentration in 12. However, there was no significant association between the extent of the increase in the plasma ET-1 levels and the incidence of the transient hypoparathyroidism. When blood was sampled at multiple sites during surgery, the plasma ET-1 concentrations tended to be higher in the internal jugular vein on the side of the preserved thyroid lobe (4.92 +/- 2.21 pg/ml) as well as on the side of the lobectomy (4.36 +/- 1.95) compared with that in the antecubital vein (3.66 +/- 1.44). Furthermore, tissue extracts from the parathyroid and thyroid contained considerably greater amounts of immunoreactive (ir-) ET-1 than most of the other tissues tested.(ABSTRACT TRUNCATED AT 250 WORDS)