Biomedical subjects
Publications and source records attributed to B Agerberth.
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Intracerebroventricular injections (140-4300 pmol) of a 60-residue polypeptide (now designated PEC-60) isolated from pig intestine produced a dose-dependent increase (peak action 21% +/- 2; ED50 value of 1.7 nmol for the peak effect) in mean arterial blood pressure (MAP) in the awake, unrestrained male rat. The heart rate (HR) was significantly reduced with the highest doses used (1400 and 4300 pmol). The pancreatic secretory trypsin inhibitor (PSTI), with a high degree of sequence similarity to PEC-60, did not significantly change MAP and HR (4300 pmol). These results may indicate a biological role for the putative PEC-60-like peptide demonstrated within central catecholamine cardiovascular neurons.
Mammalian forms of neuropeptide Y (NPY) for which the amino acid sequences have previously been determined, are the human, pig, ox, rabbit, rat, and guinea-pig polypeptides. The only difference among these forms is at position 17, where pig and ox NPY have Leu and the others Met. We now show that sheep NPY differs from all the earlier characterized mammalian forms of NPY by having Asp instead of Glu at position 10. At position 17 it has Leu as do both pig and ox NPY. Consequently, 3 different structural types of mammalian NPY are now known.
We have isolated from pig intestine a 60-residue polypeptide initially identified by its inhibition of glucose-induced insulin secretion from perfused pancreas. The amino acid sequence of this porcine polypeptide was determined and found to be markedly similar to that of the pancreatic secretory trypsin inhibitor (41% residue identities). Furthermore, the disulfide arrangements of these two proteins appear identical, suggesting related overall conformations. However, the polypeptide, now named PEC-60 (peptide with N-terminal glutamic acid, C-terminal cysteine, and a total of 60 residues), was found not to inhibit trypsin. The amino acid sequence is also similar to that of a peptide recently isolated from rat bile/pancreatic juice which stimulates the release of cholecystokinin. The biological role of PEC-60 is not known, but the effect on insulin secretion and the homologies observed suggest important biological activities and interesting structural relationships.
The polypeptide DBI (diazepam-binding inhibitor) has been purified from the porcine upper intestine, where it is abundant. Porcine mature DBI is composed of 86 amino acid residues and has a blocked N-terminus. The primary structure, the first DBI structure determined at the protein level, differs from those indirectly deduced for human and rat DBI at 11 and 17 positions, respectively. In total, the three mammalian DBIs differ at 22 positions but have exactly identical C-terminal 11-residue segments, highly charged and ending with C-terminal isoleucine. The porcine DBI inhibits both the early and the late phase of glucose-induced insulin release from the isolated perfused rat pancreas. Thus, the results identify by direct analysis the presence of DBI at a non-cerebral localization (gut), establish a novel structural form (porcine) and demonstrate a novel bioactivity (on insulin release). These aspects are of special interest in relation to the conserved segments, including the one at the C-terminal end, which may constitute functionally important parts of the polypeptide. It is possible that DBI belongs to a new family of gut polypeptides which inhibit glucose-mediated insulin release by hormonal and/or neurocrine mechanisms.