D. G. Gardner

Divalent cation metabolism: Familial hypocalciuric hypercalcemia versus typical primary hyperparathyroidism

Abstract Twenty-three members of three families with a syndrome of hypercalcemia without hypercalciuria (familial hypocalciuric hypercalcemia) were compared to a group of 64 subjects with hypercalcemia due to typical primary hyperparathyroidism. Patients with familial hypocalciuric hypercalcemia had higher creatinine clearance values than those with primary hyperparathyrodism (115 ± 27 versus 87 ± 27 ml/min/1.73 m 2 (mean ± 1 standard deviation [SD] p p p p p p p

Familial Hypocalciuric Hypercalcemia: Recognition Among Patients Referred After Unsuccessful Parathyroid Exploration

Of 67 patients referred after unsuccessful surgery for presumed primary hyperparathyroidism, six were shown to be members of kindreds with familial hypocalciuric hypercalcemia. This diagnosis had not been recognized in any of the six previosuly. Most of the remaining 61 cases had proven or probable typical primary hyperparathyroidism, and a subgroup of four had hypercalcemia with suppression of the parathyroid glands. Urine calcium excretion expressed as the calcium:creatinine clearance ratio provided an easily measurable and effective index to separate the groups with familial hypocalciuric hypercalcemia, typical primary hyperparathyroidism, and suppressed parathyroids. Thus, at least 9% of patients referred after unsuccessful parathyroidectomy had familial hypocalciuric hypercalcemia. The assessment of urine calcium excretion by indices such as the calcium:creatinine clearance ratio should facilitate recognition of this condition, which responds poorly to standard subtotal parathyroidectomy.

PARATHYROID FUNCTION AFTER PARATHYROIDECTOMY: EVALUATION BY MEASUREMENT OF URINARY cAMP

We measured urinary cyclic AMP (UcAMP) excretion after parathyroidectomy in order to assess postoperative parathyroid function. Patients undergoing successful treatment for primary hyperparathyroidism were divided into three groups based on therapy required to correct postoperative hypocalcaemia: 1 (n= 44) vitamin D not required; 2 (n= 17) vitamin D required temporarily (< 1 year); 3 (n= 10) vitamin D required permanently (> 1 year).

Preoperative Localization of Abnormal Parathyroid: Neck Massage versus Arteriography and Selective Venous Sampling

Excerpt Preoperative localization is desirable in patients with primary hyperparathyroidism who have had previous neck surgery (1-3). Arteriography and selective venous sampling, the most effective...

Inhibition of parathyroid hormone release from dispersed bovine cells by ouabain

Ouabain, at concentrations of 3 X 10(-4)-10(-3) M, inhibited secretion of PTH approximately 50% in a freshly dispersed bovine parathyroid cell preparation. This inhibition was found with both unstimulated and secretagogue-stimulated PTH release. Reductions in PTH secretion were found at all concentrations of Ca++ tested between 0.3 mM and 2.0 mM and in the presence of the divalent cation chelators EDTA and EGTA, indicating that extracellular Ca++ is not an absolute requirement for the inhibition. The ouabain inhibition did not appear to be mediated through changes in either adenylate cyclase activity or total cellular cAMP, implying a locus distal to the generation of this cyclic nucleotide. The data suggest that transmembrane potential and/or distribution of monovalent cations across the plasma membrane is important in the maintenance of PTH secretion. The mechanisms involved in this control do not appear to involve extracellular Ca++ directly.