Carrière F, Renou C, Lopez V, De Caro J, Ferrato F, Lengsfeld H, De Caro A, Laugier R, Verger R
Laboratoire de Lipolyse Enzymatique du Centre National de la Recherche Scientifique, Marseille, France.
Gastroenterology. 2000 Oct;119(4):949-60. doi: 10.1053/gast.2000.18140.
BACKGROUND & AIMS: The lipolytic potential of digestive lipases in vivo has always been deduced so far from their in vitro activities under nonphysiologic conditions. In the present study, the specific activities of human gastric lipase (HGL) and pancreatic lipase (HPL) were measured on dietary triglycerides (TGs) during test meal lipolysis.
Healthy human volunteers ingested a liquid or solid meal. The specific activities of HGL and HPL were estimated from the lipase and free fatty acid (FFA) outputs at the postpyloric and duodenal levels, respectively. Based on the in vivo data, lipolysis was also performed in vitro by mixing the meal either with gastric juice and subsequently with pancreatic juice and bile or with purified HGL and HPL. FFAs were measured by thin-layer chromatography, and the specific activities of HGL and HPL were expressed as micromoles of FFA per minute per milligram of lipase.
In vitro, the specific activities on the liquid meal TGs were 32 (gastric juice) and 34 (pure lipase) micromol x min(-1) x mg(-1) with HGL and 47 (pancreatic juice) and 43 (pure lipase) micromol x min(-1). mg(-1) with HPL. The specific activities on the solid meal TGs were 33 (gastric juice) and 32 (pure lipase) micromol x min(-1) x mg(-1) with HGL and 12 (pancreatic juice) and 15 (pure lipase) micromol x min(-1) x mg(-1) with HPL. The in vivo values obtained were in the same range. The secretory lipase outputs were 21.6+/-14.5 mg HGL and 253.5+/-95.5 mg HPL with the liquid test meal and 15.2+/-5.1 mg HGL and 202.9+/-96.1 mg HPL with the solid test meal.
The specific activities of HGL and HPL on meal TGs were much lower than those measured in vitro under optimized assay conditions (1300-8000). However, these low specific activities are enough for the meal TGs to be completely lipolysed, given the amounts of HGL and HPL secreted during a meal.
迄今为止，消化脂肪酶在体内的脂解潜力一直是根据其在非生理条件下的体外活性推断出来的。在本研究中，在试餐脂解过程中测定了人胃脂肪酶（HGL）和胰脂肪酶（HPL）对膳食甘油三酯（TGs）的比活性。
健康人类志愿者摄入液体或固体餐。分别根据幽门后和十二指肠水平的脂肪酶和游离脂肪酸（FFA）输出量估算HGL和HPL的比活性。基于体内数据，还通过将餐与胃液混合，随后与胰液和胆汁混合，或与纯化的HGL和HPL混合在体外进行脂解。通过薄层色谱法测量FFA，HGL和HPL的比活性表示为每毫克脂肪酶每分钟FFA的微摩尔数。
在体外，HGL对液体餐TGs的比活性为32（胃液）和34（纯脂肪酶）微摩尔×分钟-1×毫克-1，HPL为47（胰液）和
43（纯脂肪酶）微摩尔×分钟-1×毫克-1。HGL对固体餐TGs的比活性为33（胃液）和32（纯脂肪酶）微摩尔×分钟-1×毫克-1，HPL为12（胰液）和15（纯脂肪酶）微摩尔×分钟-1×毫克-1。获得的体内值在相同范围内。液体试餐的分泌性脂肪酶输出量为21.6±14.5毫克HGL和253.5±95.5毫克HPL，固体试餐为15.2±5.1毫克HGL和202.9±96.1毫克HPL。
HGL和HPL对餐TGs的比活性远低于在优化测定条件下（1300 - 8000）体外测量的比活性。然而，鉴于进餐期间分泌的HGL和HPL量，这些低比活性足以使餐TGs完全脂解。
