Dimeric form of calcitonin gene-related peptide in the porcine thyroid gland.
In this study we investigated peptides that increase rat platelet cAMP in porcine thyroid gland. Gel filtration of extracts from porcine thyroid gland showed high and low molecular weight activity. Low molecular weight activity contained peptides, including calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine (PHI). We isolated a high molecular weight peptide (M. W. 11,000) showing potent activity able to increase rat platelet cAMP in porcine thyroid gland. The peptide's N-terminal sequence was determined to be Ser-X-Asn-Thr-Ala-Thr- by gas phase sequencer analysis, a sequence identical to that of porcine CGRP. The peptide had CGRP immunoreactivity as well as platelet cAMP elevating activity. By gel filtration HPLC, synthetic human CGRP (M. W. 3790) was eluted in a position corresponding to M. W. 5,500. These results suggest that judging from its high molecular weight the above peptide is a dimeric form of CGRP.
First Department of Internal Medicine, Miyazaki Medical College, Japan.
Y
Y
Ichiki
K
K
Kitamura
K
K
Kangawa
T
T
Eto
D000595:Amino Acid Sequence; D000818:Animals; D001792:Blood Platelets / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000737:chemistry*; D000242:Cyclic AMP / Q000378:metabolism*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011498:Protein Precursors / Q000737:chemistry; D013552:Swine; D013961:Thyroid Gland / Q000737:chemistry*
D046911:Macromolecular Substances; D011498:Protein Precursors; D000242:Cyclic AMP; D015740:Calcitonin Gene-Related Peptide