In vivo and in vitro effects of amylin and amylin-amide on calcium metabolism in the rat and rabbit.
Amylin is a new member of the calcitonin/CGRP family: it is a 37 amino acid polypeptide which was recently isolated from amyloid deposits in pancreatic islets obtained from type II diabetics. In the present study we investigated the effect of amylin and amylin-amide on calcium metabolism in the rat and rabbit. Two main methods were used: in vivo hypocalcaemic activity was assessed by measuring plasma calcium levels after injection of the peptide in 50 g rats; and in vitro resorption of cortical bone by disaggregated rat osteoclasts was quantified by scanning electron microscopy together with image analysis. We demonstrate that amylin and amylin-amide have calcitonin-like effects: both are powerful inhibitors of osteoclastic resorption and as a consequence lower plasma calcium in both rats and rabbits. We speculate that the peptide may exert systemic or local regulatory effects on bone cells.
Datta
H K
HK
Department of Chemical Pathology and Medicine, Royal Postgraduate Medical School, London, UK.
Zaidi
M
M
Wimalawansa
S J
SJ
Ghatei
M A
MA
Beacham
J L
JL
Bloom
S R
SR
MacIntyre
I
I
D000682:Amyloid / Q000494:pharmacology*; D000818:Animals; D001862:Bone Resorption / Q000187:drug effects; D002116:Calcitonin / Q000494:pharmacology; D015740:Calcitonin Gene-Related Peptide; D002118:Calcium / Q000097:blood*; D006801:Humans; D058228:Islet Amyloid Polypeptide; D007700:Kinetics; D008297:Male; D008855:Microscopy, Electron, Scanning; D009479:Neuropeptides / Q000494:pharmacology; D010010:Osteoclasts / Q000187:drug effects / Q000502:physiology; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains
D000682:Amyloid; D058228:Islet Amyloid Polypeptide; D009479:Neuropeptides; C060605:amylinamide; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide; D002118:Calcium