Venous blood provides lower glucagon‐like peptide‐1 concentrations than arterialized blood in the postprandial but not the fasted state: Consequences of sampling methods

Abstract

Glucagon-like peptide-1 (GLP-1) displays concentration-dependent effects on metabolism, appetite and angiogenesis; therefore, accurate determination of circulating GLP-1 concentrations is important. In this study, we compared GLP-1 concentrations in venous versus arterialized blood in both fasted and fed conditions. Venous and arterialized blood samples were obtained simultaneously from 10 young, healthy men before and 30, 60 and 120 min after ingestion of 75 g glucose. Plasma GLP-1 concentrations increased in response to glucose ingestion (time effect, P < 0.01) and to a lesser extent in venous versus arterialized plasma (time × arterialization interaction, P < 0.01). Accordingly, the plasma incremental area under the curve was lower in venous versus arterialized plasma (974 ± 88 versus 1214 ± 115 pmol l (120 min) , respectively, P = 0.049). In the postprandial state, there was a positive relationship between arterialized GLP-1 concentrations and the venous-arterialized difference in GLP-1 concentrations (r = 0.51; P < 0.01). Both arterialized and venous peak GLP-1 concentrations showed positive relationships with peak arterialized insulin concentrations (both r > 0.6, P < 0.01). Venous sampling results in lower concentrations of GLP-1 in the postprandial but not the fasted state compared with arterialized blood. This absolute difference is biologically meaningful and is magnified when GLP-1 availability is high. Therefore, sampling from arterialized blood may provide a better chance of detecting small differences in postprandial GLP-1 availability with interventions. If absolute GLP-1 concentrations are of interest, the blood sampling method should be considered carefully and reported clearly.

Co-ingestion of whey protein hydrolysate with milk minerals rich in calcium potently stimulates glucagon-like peptide-1 secretion: an RCT in healthy adults

“…Therefore, as with glycaemia [22], it may be recommended to sample from arterial or arterialized blood when systemic postprandial gut hormone concentrations require accurate quantification. However, the difference in peak postprandial GLP-1 Total concentrations between arterialized and venous blood is ~ 10 pmol L −1 [35]. Consequently, the blood sampling method employed can only explain a small fraction of the remarkably high GLP-1 concentrations that we report.…”

“…Regarding the second possibility, GLP-1 concentrations are higher in arterial, compared to venous blood [34,35], presumably due to tissue uptake or binding with GLP-1 receptors. Therefore, as with glycaemia [22], it may be recommended to sample from arterial or arterialized blood when systemic postprandial gut hormone concentrations require accurate quantification.…”

Physiological responses to maximal eating in men

“…Furthermore, we obtained venous samples. Whilst the use of venous blood is appropriate in a crossover design as any differences are within-subject, our research has previously shown that arterialising venous samples by heating a dorsal hand vein can influence the measurement of postprandial glucose and GLP-1 concentrations (50,51) . Future studies should characterise the postprandial responses to nutrients using arterialised blood.…”

Racial Variations in Appetite-Related Hormones, Appetite, and Laboratory-Based Energy Intake from the E-MECHANIC Randomized Clinical Trial

“…It is possible that the short half-life of GLP-1 makes it difficult to detect differences in concentrations between AAs and Whites from venous blood [11]. One study recently showed that venous concentrations of GLP-1 are smaller and less physiologically relevant from an appetite perspective than those yielded from arterialized blood [38]. As a result, future studies may benefit from performing assessments of arterialized concentrations of GLP-1 to observe differences between AAs and Whites.…”