Parathyroid hormone secretion and serum calcium concentration--a deterministic view of its regulation.
In seven normal men we investigated the basal secretion of PTH by blood sampling in 30 sec intervals for estimation of intact PTH and at 2-min intervals for measurement of ionized calcium. In 4 of these subjects we also investigated the PTH-secretion under conditions of intermittent hypercalcemia and hypocalcemia. Our measurements demonstrate the existence of three time scales in the secretion of PTH, viz. short-term pulses (faster than 2 min), an intermediate pattern of adjusting PTH levels to changed Ca2+ averages, and finally a long-term coupling between PTH and Ca2+ averages after 20 min. Ionized calcium controls the long-term regulation and intermediate adaptation mechanisms, but the short-term fluctuations seem to be due to spontaneous secretion.
Heidbreder
E
E
Nephrologische Abteilung Medizinische Universitätsklinik, Würzburg, Germany.
Naujoks
H
H
Brosa
U
U
Schramm
L
L
Götz
R
R
D000328:Adult; D002118:Calcium / Q000097:blood*; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood / Q000378:metabolism*
D010281:Parathyroid Hormone; D002118:Calcium