Parathyroid function in cardiac transplant patients: evaluation during physical exercise.
The survival rate of heart transplant patients has increased considerably since the development of new immunosuppressive drugs. In the long term, however, cardiac transplantation results in a high incidence of osteoporosis which represents a major functional handicap. To examine whether patients in the early stages have impaired phosphocalcic metabolism, intact parathyroid hormone (PTH 1-84), native osteocalcin, ionized Ca++ and pH were measured at rest and during muscular exercises a dynamic test used to override circadian and ultradian PTH variations. A group of 12 patients receiving the usual immunosuppressive therapy, which is mainly an association of cyclosporin and prednisolone, and 8 sedentary control subjects performed a square-wave endurance test at the same relative intensity for 30 min. No patient had previous bone disease and the period since transplantation was 12.2 +/- 2.7 months. For the transplant patients, initial PTH concentrations and responses to exercise were higher (P < 0.01) compared to the control subjects with a dramatic increase after 10 min of recovery. From higher (P < 0.001) resting concentrations, osteocalcin further increased during exercise (P < 0.01) in the heart transplant group but not in the control subjects. In both groups pH showed the same time-course with a rapid fall during exercise (P < 0.05) and Ca++ concentrations increased during the exercise period. (P < 0.01 for patients; P < 0.05 for controls) with a significant fall in both groups after 10 min of recovery (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Brandenberger
G
G
Laboratoire de Physiologie et de Psychologie Environnementales, CNRS-LPPE 21, Strasbourg, France.
Schnedecker
B
B
Spiegel
K
K
Mettauer
B
B
Geny
B
B
Sacrez
J
J
Lampert
E
E
Lonsdorfer
J
J
D000328:Adult; D001846:Bone Development / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D016027:Heart Transplantation / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D015675:Osteocalcin / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D010280:Parathyroid Glands / Q000502:physiology*; D010281:Parathyroid Hormone / Q000097:blood
D010281:Parathyroid Hormone; D015675:Osteocalcin; D002118:Calcium