Biphasic calcitonin release in the newborn rat.
A sustained elevation in plasma calcium levels was induced in 2-h-old fasted newborn rats by gavage of calcium (200 mg Ca/kg body weight). Plasma calcium was already increased 2 minutes after gavage (1.2 mg/100 ml) and subsequently raised until 30 minutes (13.15 +/- 0.15 mg/100 ml versus 7.70 +/- 0.30 mg/100 ml in controls: gavage with saline only). Then, a slow decrease in plasma calcium levels was observed 60 and 90 minutes after gavage. In response, a peak in plasma calcitonin concentrations occurred 5 minutes after gavage (1.25 +/- 0.10 ng/ml verus < 0.3 ng/ml in controls); plasma calcitonin levels fell from 5 to 30 minutes after gavage and raised again 60 and 90 minutes after gavage. Plasma phosphate levels were decreased from 30 to 90 minutes after calcium gavage, may be in relation to the increased calcitonin secretion.
D000818:Animals; D000831:Animals, Newborn / Q000097:blood*; D002116:Calcitonin / Q000097:blood*; D002118:Calcium / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D010710:Phosphates / Q000097:blood; D051381:Rats
D010710:Phosphates; D002116:Calcitonin; D002118:Calcium