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The isolation, sequence, bioactivity and biosynthetic significance of two bombesin-like peptides from chicken proventriculus
64 THE ISOLATION, SEQUENCE,BIOACTMTY AND BIOSYNTHETICSIGNIFICANCE OF TWO BONIBESIN-LIKEPEPTIDESFROM CHICKEN PROVENTRICULUS
B.3. Campbell, *3.Young, R.Dimaline, and G.3. Dockray. Physiological Laboratory, University of I_i~erpool, Liverpool, LJ.K. and *I.C.I., AlderIey Park, Cheshire, U.K. We have sought to characterize the bombesin (BN)-related pePtides found in high concentrations in the chicken proventriculus. Isolation was monitored using Cterminal specific BN antibody (L90) in RIA; acid extraction yielded 517.5 + 52.5 pmol/g (n = lb.). RIA using neuromedin B specific antiserum L267 revealed negligible amounts of a c t i v i t y in the proventriculus (< 2.0 pmoI/g). Two BN-immunoreactive peptides were isolated by reverse-phase I_iChroprep RP8, Sephadex G25, C[vl.52 (ion exchange) chromatography and reverse-phase HPLC. Sequence data from automated Edman degradation showed that one peptide corresponded to a 27-residue gastrin releasing peptide (GRP) previously identified by McDonald eL al (FEBS Lefts, 122, 4548, 1980); the other corresponded to its C - t e r m i n a l hexapeptide (GRP6). There was no evidence to suggest that the smaller form was an a r t i f a c t of degradation, so it is proposed that GRP6 is formed by trypsin-like cleavage of GRP27, yielding the Cterminal decapeptide, followed by two cycles of dipeptidyl aminopeptidase-like cleavage. In urethane anaesthetised turkeys avian GRP27 and B14 were virtually equipotent in increasing the secretion of pancreatic enzymes (dose range 6 to 100 pmol/kg, n = 6) and gastric acid 0.5 to 25 pmol/kg, n = ]). GFLP6, at 6400 pmol/kg, had a negligible effect on either pancreatic or gastric secretion. Summary_: i) The main bioactive representative of the BN family in the avian proventricu-'-[u's is GRP 27; ii) GFLP27 is a putative hormonal regulator of avian pancreatic and gastric secretion; iii) GRP6 is inactive, but may be an intracellular metabolite generated by an unusual pathway.
INVOLVEMENT OF ANGIOTENSIN IN HYPERMETABOLIC RESPONSES TO INJURY AND INTERLEUKIN-16 IN THE RAT A.L. COOPER, D. MCCARTHY, C.T. O'SHAUGHNESSY and N.J. ROTHWELL, Neuropharmacology Group, Oept of Physiological Sciences, University of Manchester, Manchester M13 9PT Cerebral ischaemia in the rat is accompanied by a rise in metabolic rate ~hich shares common effector mechanisms with the thermogenic response to endogenous pyrogens. We have studied the involvement of brain angiotensin in these actions by administration of the angiotensin converting enzyme inhibitor, captopril, to animals exhibiting hypermetabolism in response to central administration of the endogenous pyrogen, interleukin-1 or induction of cerebral ischaemia. Rats were either injected with recombinant human interleukin-l~ (Sng, icy) Dr subjected to middle cerebral artery (MCA) occlusion resulting in an ischaemic cerebral insult to the cortex and basal ganglia. Control animals ~ere subjected to sham-surgery. Interleukin-1 and cerebral ischaemia induced increases in oxygen consumption (V02) of 14.3±4.5 and 13.0±2.0% respectively (P
B.3. Campbell, *3.Young, R.Dimaline, and G.3. Dockray. Physiological Laboratory, University of I_i~erpool, Liverpool, LJ.K. and *I.C.I., AlderIey Park, Cheshire, U.K. We have sought to characterize the bombesin (BN)-related pePtides found in high concentrations in the chicken proventriculus. Isolation was monitored using Cterminal specific BN antibody (L90) in RIA; acid extraction yielded 517.5 + 52.5 pmol/g (n = lb.). RIA using neuromedin B specific antiserum L267 revealed negligible amounts of a c t i v i t y in the proventriculus (< 2.0 pmoI/g). Two BN-immunoreactive peptides were isolated by reverse-phase I_iChroprep RP8, Sephadex G25, C[vl.52 (ion exchange) chromatography and reverse-phase HPLC. Sequence data from automated Edman degradation showed that one peptide corresponded to a 27-residue gastrin releasing peptide (GRP) previously identified by McDonald eL al (FEBS Lefts, 122, 4548, 1980); the other corresponded to its C - t e r m i n a l hexapeptide (GRP6). There was no evidence to suggest that the smaller form was an a r t i f a c t of degradation, so it is proposed that GRP6 is formed by trypsin-like cleavage of GRP27, yielding the Cterminal decapeptide, followed by two cycles of dipeptidyl aminopeptidase-like cleavage. In urethane anaesthetised turkeys avian GRP27 and B14 were virtually equipotent in increasing the secretion of pancreatic enzymes (dose range 6 to 100 pmol/kg, n = 6) and gastric acid 0.5 to 25 pmol/kg, n = ]). GFLP6, at 6400 pmol/kg, had a negligible effect on either pancreatic or gastric secretion. Summary_: i) The main bioactive representative of the BN family in the avian proventricu-'-[u's is GRP 27; ii) GFLP27 is a putative hormonal regulator of avian pancreatic and gastric secretion; iii) GRP6 is inactive, but may be an intracellular metabolite generated by an unusual pathway.
INVOLVEMENT OF ANGIOTENSIN IN HYPERMETABOLIC RESPONSES TO INJURY AND INTERLEUKIN-16 IN THE RAT A.L. COOPER, D. MCCARTHY, C.T. O'SHAUGHNESSY and N.J. ROTHWELL, Neuropharmacology Group, Oept of Physiological Sciences, University of Manchester, Manchester M13 9PT Cerebral ischaemia in the rat is accompanied by a rise in metabolic rate ~hich shares common effector mechanisms with the thermogenic response to endogenous pyrogens. We have studied the involvement of brain angiotensin in these actions by administration of the angiotensin converting enzyme inhibitor, captopril, to animals exhibiting hypermetabolism in response to central administration of the endogenous pyrogen, interleukin-1 or induction of cerebral ischaemia. Rats were either injected with recombinant human interleukin-l~ (Sng, icy) Dr subjected to middle cerebral artery (MCA) occlusion resulting in an ischaemic cerebral insult to the cortex and basal ganglia. Control animals ~ere subjected to sham-surgery. Interleukin-1 and cerebral ischaemia induced increases in oxygen consumption (V02) of 14.3±4.5 and 13.0±2.0% respectively (P