Direct in vivo assessment of parathyroid hormone-calcium relationship curve in renal patients.
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)
Messa
P
P
Nephrology Division, Ospedale S. Maria della Misericordia, Udine, Italy.
Vallone
C
C
Mioni
G
G
Geatti
O
O
Turrin
D
D
Passoni
N
N
Cruciatti
A
A
D000328:Adult; D000368:Aged; D002112:Calcifediol / Q000097:blood; D002116:Calcitonin / Q000097:blood; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood*; D002125:Calcium Gluconate / Q000008:administration & dosage; D004492:Edetic Acid / Q000008:administration & dosage; D005919:Glomerular Filtration Rate; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000209:etiology; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood / Q000378:metabolism*
D010281:Parathyroid Hormone; D002116:Calcitonin; D004492:Edetic Acid; D002117:Calcitriol; D002112:Calcifediol; D002125:Calcium Gluconate; D002118:Calcium