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Chromatographic study on immunoreactive somatostatin, vasoactive intestinal peptide, substance P, and cholecystokinin in plasma
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CHROMATOGRAPIIIC STUDY ON I M ~ N O R E A C T I V E SO~TOSTATIN,VASOACTIVE INTESTINAL PEPTIDE,SUBSTANCE P,AND CHOLECYSTOKININ IN PLASMA. J.A.Chayvialle,F.Descos, S.Dani~re and R.Rambliere. INSERM,U.45,Hop.E-Herriot,Lyon,France. In an attempt to characterize the somatostatin (STS),vasoactive intestinal peptide (VlP),cholecystokinin-33 (CCK) and substance-P (sP) -like components detected by radioirmnunoassay in plasma,pools of I00 ml plasma were sampled before and 1 hour after food in 6 healthy volunteers.After acetic acid- acetone extraction and lyophilisation,the extracts were chromatographed on 1.5 x I00 cm G50 superfine Sephadex columns.The eluted fractions were tested in assay systems that recognize respectively the entire (porcine) VIP molecule,the 6-11 portion of the STS tetradecapeptide,C-terminal fragments longer than the sP hexapeptide,and specifically the sulfated C-terminal portion of CCK. The elution volumes of the preparations used for column calibration were 0.3 for CCK, 0.35 for VIP, 0.55 for the recently characterized STS octacosapeptide, 0.6 for the sP undecapeptide and 0.75 for the STS tetradecapeptide (for albumin =0 and 125 Iodine = 1.0). Components displaying STS and VIP immunoreactivity were detected in extracts of both fasting and postprandial plasma, coeluting respectively with porcine VIP,and with both the tetradecapeptide and the octacosapeptide of STS.In contrast,no sP-component was detected in fasting nor postprandial plasma,while some CCK immunoreactivity was detected in only some of the postprandial plasma extracts.Further components were eluted in a volume of 0.8-0.9,but may have reflected non-specific interference from the extracts and remain to be characterized in different systems.Thus,among the four peptides tested,and given the present experimental conditions,only STS and VIP like components were consistently detected in plasma extracts drawn pre- and postprandially from healthy human subjects.
EFFECT OF FOOD ON P L A S ~ IM>~NOREACTIVE SOMATOSTATIN, VASOACTIVE INTESTINAL PEPTIDE, AND SUBSTANCE-P IN ~ N . J.A.Chayvialle,J.Forichon,F.Descos,S.Dani~re and R.Rambliere. INSERM,U.45,Hopital E-Herriot,Lyon,France. The effect of a physiological solid/liquid test-meal on three peptides thought to act as neurotransmltters or as paracrine substances was investigated in 8 healthy volunteers given a 6]5 kcal protein-rich meal. The plasma immunoreactive somatostatin (STS),vasoactive intestinal peptide (VIP) and substance-P (sP) concentrations were measured with specific assays recognizing the 6-11 portion of the STS tetradecapeptide, the entire (porcine) molecule of VIP, and C-terminal fragments longer than the sP hexapeptide. The test-meal induced a significant rise of plasma STS,from mean basal 25.6 + 3.9 to a peak value of 45.4 ~ 7.8 pg/ml 75 minutes after food ingestion. In contrast,the plasma concentrations of VIP and sP did not vary significantly in the postprandial period from respective mean basal concentrations of 21.2 + 3.0 and 12.1 + 1.9 pg/ml. The STS response to food was further tested in 7 healthy subjects given on separate days isocaloric test-meals consisting predominantly of proteins,carbohydrates or lipids,and added with 15 g lactulose for measurement of the oro-cecal transit time by the hydrogen breath-test. The protein meal induced a significant rise of plasma STS, from 24.0 + 4.1 to 46.0 + 11.4 pg/ml, with an integrated peptide response of 1.61 ~ ~.67 ng.240 min/m~. The response was similar after the lipid- (1.85 ± 0.51 ng.240 min/ml) but slightly lower after the carbohydrate-rich meal (0.79 ± 0.62 ng.240 min/ ml). Thus,in contrast with the lack of variation of plasma VIP and plasma sP concentrations after food ingestion, a physiological test-meal induces a significant STS response,which appears to be mainly induced (directly or indirectly) by proteins and lipids.
CHROMATOGRAPIIIC STUDY ON I M ~ N O R E A C T I V E SO~TOSTATIN,VASOACTIVE INTESTINAL PEPTIDE,SUBSTANCE P,AND CHOLECYSTOKININ IN PLASMA. J.A.Chayvialle,F.Descos, S.Dani~re and R.Rambliere. INSERM,U.45,Hop.E-Herriot,Lyon,France. In an attempt to characterize the somatostatin (STS),vasoactive intestinal peptide (VlP),cholecystokinin-33 (CCK) and substance-P (sP) -like components detected by radioirmnunoassay in plasma,pools of I00 ml plasma were sampled before and 1 hour after food in 6 healthy volunteers.After acetic acid- acetone extraction and lyophilisation,the extracts were chromatographed on 1.5 x I00 cm G50 superfine Sephadex columns.The eluted fractions were tested in assay systems that recognize respectively the entire (porcine) VIP molecule,the 6-11 portion of the STS tetradecapeptide,C-terminal fragments longer than the sP hexapeptide,and specifically the sulfated C-terminal portion of CCK. The elution volumes of the preparations used for column calibration were 0.3 for CCK, 0.35 for VIP, 0.55 for the recently characterized STS octacosapeptide, 0.6 for the sP undecapeptide and 0.75 for the STS tetradecapeptide (for albumin =0 and 125 Iodine = 1.0). Components displaying STS and VIP immunoreactivity were detected in extracts of both fasting and postprandial plasma, coeluting respectively with porcine VIP,and with both the tetradecapeptide and the octacosapeptide of STS.In contrast,no sP-component was detected in fasting nor postprandial plasma,while some CCK immunoreactivity was detected in only some of the postprandial plasma extracts.Further components were eluted in a volume of 0.8-0.9,but may have reflected non-specific interference from the extracts and remain to be characterized in different systems.Thus,among the four peptides tested,and given the present experimental conditions,only STS and VIP like components were consistently detected in plasma extracts drawn pre- and postprandially from healthy human subjects.
EFFECT OF FOOD ON P L A S ~ IM>~NOREACTIVE SOMATOSTATIN, VASOACTIVE INTESTINAL PEPTIDE, AND SUBSTANCE-P IN ~ N . J.A.Chayvialle,J.Forichon,F.Descos,S.Dani~re and R.Rambliere. INSERM,U.45,Hopital E-Herriot,Lyon,France. The effect of a physiological solid/liquid test-meal on three peptides thought to act as neurotransmltters or as paracrine substances was investigated in 8 healthy volunteers given a 6]5 kcal protein-rich meal. The plasma immunoreactive somatostatin (STS),vasoactive intestinal peptide (VIP) and substance-P (sP) concentrations were measured with specific assays recognizing the 6-11 portion of the STS tetradecapeptide, the entire (porcine) molecule of VIP, and C-terminal fragments longer than the sP hexapeptide. The test-meal induced a significant rise of plasma STS,from mean basal 25.6 + 3.9 to a peak value of 45.4 ~ 7.8 pg/ml 75 minutes after food ingestion. In contrast,the plasma concentrations of VIP and sP did not vary significantly in the postprandial period from respective mean basal concentrations of 21.2 + 3.0 and 12.1 + 1.9 pg/ml. The STS response to food was further tested in 7 healthy subjects given on separate days isocaloric test-meals consisting predominantly of proteins,carbohydrates or lipids,and added with 15 g lactulose for measurement of the oro-cecal transit time by the hydrogen breath-test. The protein meal induced a significant rise of plasma STS, from 24.0 + 4.1 to 46.0 + 11.4 pg/ml, with an integrated peptide response of 1.61 ~ ~.67 ng.240 min/m~. The response was similar after the lipid- (1.85 ± 0.51 ng.240 min/ml) but slightly lower after the carbohydrate-rich meal (0.79 ± 0.62 ng.240 min/ ml). Thus,in contrast with the lack of variation of plasma VIP and plasma sP concentrations after food ingestion, a physiological test-meal induces a significant STS response,which appears to be mainly induced (directly or indirectly) by proteins and lipids.