Mizuma H, Legardeur B Y, Prasad C, Hilton C W
Department of Medicine, LSU Medical Center, New Orleans 70112, USA.
J Am Coll Nutr. 1996 Apr;15(2):175-9. doi: 10.1080/07315724.1996.10718585.
Food contains a number of peptides with potential bioactivity. We previously found ng/mliter to mcg/mliter quantities of cyclo(His-Pro)-like immunoreactivity in a number of foods and nutritional supplements. A number of activities have been attributed to cyclo(His-Pro) (CHP), including appetite inhibition and inhibition of insulin secretion in vitro. We wondered whether the cyclo(His-Pro)-like immunoreactivity present in nutritional supplements might be absorbed and, if so, whether parameters of insulin secretion would be altered.
After performing a pilot study which suggested some common nutritional supplements contain CHP, a follow-up study was done to confirm and expand the findings of the pilot study. Eight fasting volunteers ingested approximately 250 mL of a CHP-containing supplement one day, and then an equienergetic CHP-free supplement the next.
Blood drawn for CHP, insulin, glucose, and C-peptide a number of times on both days revealed that when volunteers ingested CHP-containing supplements, CHP levels at 120 minutes were significantly higher than baseline (7.69 +/- 0.50 pmol/mL vs. 9.18 +/- 0.48 pmol/mL; p = 0.011 in the CHP group and 7.90 +/- 0.85 pmol/mL vs. 7.22 +/- 0.73 pmol/mL, p > 0.3 in the CHP-free group) and significantly higher than levels achieved when they drank CHP-free supplements. Levels of glucose, insulin, and C-peptide were not different in the two groups.
CHP in nutritional supplements may be absorbed when ingested orally and does not grossly affect glucose or parameters of insulin secretion.
食物中含有许多具有潜在生物活性的肽。我们之前在多种食物和营养补充剂中发现了纳克/升微克/升数量级的环（组氨酸 - 脯氨酸）样免疫反应性。环（组氨酸 - 脯氨酸）（CHP）具有多种活性，包括体外抑制食欲和抑制胰岛素分泌。我们想知道营养补充剂中存在的环（组氨酸 - 脯氨酸）样免疫反应性是否会被吸收，如果会，胰岛素分泌参数是否会改变。
在进行了一项初步研究，提示一些常见的营养补充剂含有CHP之后，进行了一项后续研究以确认并扩展初步研究的结果。八名空腹志愿者一天摄入约250毫升含CHP的补充剂，然后第二天摄入等能量的不含CHP的补充剂。
在两天内多次采集血液检测CHP、胰岛素、葡萄糖和C肽，结果显示，当志愿者摄入含CHP的补充剂时，120分钟时的CHP水平显著高于基线（CHP组中7.69±0.50皮摩尔/毫升对9.18±0.48皮摩尔/毫升；p = 0.011，不含CHP组中7.90±0.85皮摩尔/毫升对7.22±0.73皮摩尔/毫升，p>0.3），且显著高于饮用不含CHP补充剂时的水平。两组的葡萄糖、胰岛素和C肽水平没有差异。
营养补充剂中的CHP口服摄入后可能会被吸收，并且不会对葡萄糖或胰岛素分泌参数产生明显影响。
