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 Cr(51)EDTA clearance; (3) the sigmoidal PTH-ionized calcium relation curve, by means of a hypocalcemic stimulating test (Na-2-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. The main results were: (1) the progressive reduction of GFR was accompanied by an increase in the maximum secretory capacity of PTH, without any change in setpoint values; (2) in addition to the already known factors, CT seems to be, in some as yet undefined way, related to PTH hypersecretion in the course of CRF.
Direct in vivo assessment of parathyroid hormone-calcium relationship curve in renal patients / P. Messa, C. Vallone, G. Mioni, O. Geatti, D. Turrin, N. Passoni, A. Cruciatti. - In: KIDNEY INTERNATIONAL. - ISSN 0085-2538. - 46:6(1994 Dec), pp. 1713-1720.
|Titolo:||Direct in vivo assessment of parathyroid hormone-calcium relationship curve in renal patients|
|Parole Chiave:||Secondary hyperparathyroidism; sigmoidal relationship; calcemic response; skeletal resistance; gland function; failure; calcitriol; uremia; phosphorus; secretion|
|Settore Scientifico Disciplinare:||Settore MED/14 - Nefrologia|
|Data di pubblicazione:||dic-1994|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1038/ki.1994.473|
|Appare nelle tipologie:||01 - Articolo su periodico|