Effect of Carbohydrate on Portal Vein Blood Flow During Exercise

Abstract

Effects of carbohydrate ingestion and exercise on portal vein blood flow were studied. Flow was measured by pulsed-electronic Doppler. Eight male subjects performed four tests after a standardised breakfast and 5 h fast. Beverages were CHO (10 % glucose, 30 mmol · l^-1 NaCl) and W (water, 30 mmol · l^-1 NaCl). Exercise experiments comprised a resting measurement, 10 min warm-up and 60 min 70 % VO₂max cycling. Every 10 min subjects stopped cycling briefly (∼ 30 s) for measurements. Beverage was consumed after warm-up (500 ml) and at 20 and 40 min (250 ml). Similar tests were done at rest. Blood samples were taken concurrently with flow measurements for hormonal concentrations. Exercise decreased blood flow (repeated measures ANOVA, p < 0.0001) and carbohydrate ingestion increased flow (p = 0.015). At rest, flow was greater with CHO than with W at 20 (177 ± 31; 101 ± 25 %, resp.) (mean ± SE), 30 (209 ± 37; 120 ± 20 %), 40 (188 ± 32; 108 ± 12 %), and 60 min (195 ± 19; 112 ± 12 %) (1-way ANOVA, Fisher's PLSD, p < 0.05). Flow was similar during exercise with CHO and W, with a tendency for CHO to maintain flow better, at 10 (124 ± 27; 77 ± 21 %), 20 (81 ± 10; 60 ± 13 %), 30 (106 ± 26; 56 ± 10 %), 40 (109 ± 28; 54 ± 8 %), 50 (85 ± 17; 54 ± 13 %), and 60 min (61 ± 15; 47 ± 7 %). A positive correlation between glucagon and flow and an inverse correlation between noradrenaline and flow were observed. Exercise reduces, and carbohydrate increases, portal vein flow. Changes in plasma concentrations suggest that noradrenaline and glucagon, respectively, may play a role in modulating flow.

Splanchnic - sympathoadrenergic - noradrenaline - Doppler

References

• 1 Bearn A G, Billing B H, Sherlock S. The effect of adrenaline and noradrenaline on hepatic flow and splanchnic carbohydrate metabolism in man.  J Physiol. 1951;  39 430-441
• 2 Braatvedt G, Stanners A, Newrick P G, Halliwell M, Corrall R JM. Evidence against a putative role for glucagon as a physiological vasodilator in man.  Clin Sci. 1993;  84 193-199
• 3 Chaudhuri K R, Thomaides T, Mathias C J. Abnormality of superior mesenteric artery blood flow responses in human sympathetic failure.  J Physiol. 1992;  457 477-489
• 4 Eriksen M, Waaler B A. Priority of blood flow to splanchnic organs in humans during pre- and post-meal exercise.  Acta Physiol Scand. 1994;  150 363-372
• 5 Feruglio F S, Greco F, Cesano L, Clongo P G, Sardi G, Chiandussi L. The effects of glucagon on systemic and on net peripheral and hepatosplanchnic balance of glucose, lactic and pyruvic acids in normal subjects and cirrhotics.  Clin Sci. 1966;  30 43-50
• 6 Fronek K, Fronek A. Combined effect of exercise and digestion on hemodynamics in conscious dogs.  Am J Physiol. 1970;  218 555-559
• 7 Granger D N, Kveitys P R, Wilborn W H, Mortillaro N A, Taylor A E. Mechanism of glucagon-induced intestinal secretion.  Am J Physiol. 1980;  239 30-38
• 8 Iwao T, Toyonaga A, Ikegami M, Sumino M, Oho K, Sakaki M, Shigemori H, Tanikawa K, Iwao J. Effects of exercise-induced sympathoadrenergic activation on portal blood flow.  Dig Dis Sci. 1995;  40 48-51
• 9 Mailman D. Relationships between intestinal absorption and hemodynamics.  Ann Rev Physiol. 1982;  44 43-55
• 10 Okazaki K, Miyazaki M, Onishi S, Ito K. Effects of food intake and various extrinsic hormones on portal blood flow in patients with liver cirrhosis demonstrated by pulsed Doppler with the octoson.  Scand J Gastroenterol. 1986;  21 1029-1038
• 11 Qamar M I, Read A E. Effects of exercise on mesenteric blood flow in man.  Gut. 1987;  28 583-587
• 12 Rehrer N J, Smets A, Reynaert H, Goes E, De Meirleir K. Effect of exercise on portal vein blood flow in man.  Med Sci Sports Exerc. 2001;  33 1533-1537
• 13 Sabba C, Ferraioli G, Genecin P, Colombato L, Buonamico P, Lerner E, Taylor K J, Groszmann R J. Evaluation of postprandial hyperemia in superior mesenteric artery and portal vein in healthy and cirrhotic humans: an operator-blind Echo-Doppler study.  Hepatology. 1991;  13 714-718
• 14 Shepherd A P. Intestinal 0₂ uptake during sympathetic stimulation and partial occlusion.  Am J Physiol. 1979;  236 731-735
• 15 Varro V, Blaho G, Csernay L, Jung L, Szarvas F. Effect of decreased local circulation on the absorptive capacity of a small-intestine loop in the dog.  Am J Digestive Dis. 1965;  10 170-177
• 16 Williams J H, Mager M, Jacobson E D. Relationship of mesenteric blood flow to intestinal absorption of carbohydrates.  J Lab Clin Med. 1964;  63 853-863