Direct in vivo assessment of parathyroid hormone-calcium relationship curve in renal patients

Kidney Int. 1994 Dec;46(6):1713-20. doi: 10.1038/ki.1994.473.


Secondary hyperparathyroidism (SHP) is a well documented finding even in the early stages of chronic renal failure (CRF). A sigmoidal relationship, fitting a four parameter model, links PTH secretion rate and calcium concentration changes. To our knowledge, PTH secretory parameters have only been studied in uremic patients who are in dialysis treatment. As a result of these studies, a possible role for derangement in setpoint values (that is, the serum calcium concentration corresponding to the mid-range value on the sigmoidal curve) has been suggested in the pathogenesis of SHP in CRF. Our study was undertaken to gain insight into the calcium-PTH relationship curve in the first course of CRF and to assess whether a change in any of the secretory parameters is related to the beginning of SHP. We studied 27 male renal patients with a variable degree of renal function (creatinine clearance 12 to 164 ml/min) and 9 control subjects. In all patients and controls the following parameters were evaluated: (1) basal 1,25(OH)2 vitamin D, 25(OH)vitamin D, calcitonin (CT), intact PTH; (2) GFR by Cr51EDTA clearance; (3) the sigmoidal PTH-ionized calcium relation curve, by means of a hypocalcemic stimulating test (Na2-EDTA 37 mg/kg body weight/2 hr) and a hypercalcemic test (Ca gluconate giving 8 mg/kg of body weight/2 hr of Ca element), performed on two consecutive days.(ABSTRACT TRUNCATED AT 250 WORDS)

MeSH terms

  • Adult
  • Aged
  • Calcifediol / blood
  • Calcitonin / blood
  • Calcitriol / blood
  • Calcium / blood*
  • Calcium Gluconate / administration & dosage
  • Edetic Acid / administration & dosage
  • Glomerular Filtration Rate
  • Humans
  • Hyperparathyroidism, Secondary / etiology
  • Kidney Failure, Chronic / blood
  • Kidney Failure, Chronic / complications
  • Kidney Failure, Chronic / physiopathology*
  • Kinetics
  • Male
  • Middle Aged
  • Parathyroid Hormone / blood
  • Parathyroid Hormone / metabolism*


  • Parathyroid Hormone
  • Calcitonin
  • Edetic Acid
  • Calcitriol
  • Calcifediol
  • Calcium Gluconate
  • Calcium