Intestinal Absorption Kinetics Research Articles

Comparative study on intestinal absorption kinetics of main active components in Sini Decoction and its separated recipes

This paper aims to study the difference in the intestinal absorption kinetics of main active components of Sini decoction and its separated recipes and explain the scientificity and rationality of the compatibility of Sini Decoction. A in situ intestinal perfusion rat model was established to evaluate the differences in the absorption of benzoylmesaconine, benzoylaconine, benzoylhypacoitine, mesaconitine, hypaconitine, glycyrrhizic acid, liquiritin and 6-gingerol from Sini Decoction and its separated recipes in the duodenum, jejunum and ileum by high performance liquid chromatography(HPLC). The results indicated that the Sini Decoction group was superior to the Aconiti Lateralis Radix Praeparata group in terms of absorption degree and rate for aconitum alkaloids. The absorption of benzoylmesaconine and hypaconitine in the duodenum, jejunum and ileum was faster and stronger in the Sini Decoction group(P<0.05). The absorption degree of glycyrrhizic acid in the duodenum was significantly higher in the Sini Decoction group than in the Glycyrrhizae Radix et Rhizoma group and the Glycyrrhizae Radix et Rhizoma-Zingiberis Rhizoma group(P<0.05). The absorption rate and degree of 6-gingerol in the ileum in the Sini Decoction group were significantly higher than those in the Zingiberis Rhizoma group(P<0.05). In short, Zingiberis Rhizoma and Glycyrrhizae Radix et Rhizoma can promote the absorption of aconitum alkaloids in different intestinal segments, which reflects the scientific composition of Sini Decoction.

Prediction of Pharmacokinetics of IDP-73152 in Humans Using Physiologically-Based Pharmacokinetics.

IDP-73152, a novel peptide deformylase inhibitor with an antibacterial effect against Gram-positive bacteria, is in phase I development. The objective of this study was to develop a physiologically-based pharmacokinetic model (PBPK) for IDP-73152 in animals, and to extend the model to humans. Biopharmaceutical properties of IDP-73152 are determined using in vitro/in vivo experimentations for the PBPK model. A transit model consisting of gastrointestinal segments is applied for an estimation of the intestinal absorption kinetics. The PBPK model of IDP-73152 in rats is able to appropriately predict the plasma concentration–time profiles after the administration of IDP-73152 at different doses and by different routes (combined absolute average fold error (cAAFE), 1.77). The model is also found to be adequate in predicting the plasma concentration–time profiles of IDP-73152 in mice (cAAFE 1.59) and dogs (cAAFE 1.42). Assuming the oral administration of IDP-73152 to humans at doses of 640 and 1280 mg, the model is able to reproduce the concentration–time profiles obtained in humans (cAAFE 1.38); therefore, these observations indicate that the PBPK model used for IDP-73152 is applicable to animal species and humans. This model may be useful in predicting efficacious doses of IDP-73152 for the management of infectious disease in humans.

The mechanism of increased intestinal palmitic acid absorption and its impact on hepatic stellate cell activation in nonalcoholic steatohepatitis

Dietary palmitic acid (PA) promotes liver fibrosis in patients with nonalcoholic steatohepatitis (NASH). Herein, we clarified the intestinal absorption kinetics of dietary PA and effect of trans-portal PA on the activation of hepatic stellate cells (HSCs) involved in liver fibrosis in NASH. Blood PA levels after meals were significantly increased in patients with NASH compared to those in the control. Expression of genes associated with fat absorption and chylomicron formation, such as CD36 and MTP, was significantly increased in the intestine of NASH model rats compared with that in the controls. Plasma levels of glucagon-like peptide-2, involved in the upregulation of CD36 expression, were elevated in NASH rats compared with those in the controls. Furthermore, portal PA levels after meals in NASH rats were significantly higher than those in control and nonalcoholic fatty liver rats. Moreover, PA injection into the portal vein to the liver in control rats increased the mRNA levels associated with the activation of HSCs. Increased intestinal absorption of diet-derived PA was observed in NASH. Thus, the rapid increase in PA levels via the portal vein to the liver may activate HSCs and affect the development of liver fibrosis in NASH.

Possible Role of P-Glycoprotein in Cyclosporine -Acitretin Drug Interaction

P-glycoprotein, an efflux transporter prevents intracellular accumulation of xenobiotics. Cyclosporine A and acitretin are used to treat psoriasis. The present research work aims to investigate the possible role of P-glycoprotein in Cyclosporine- Acitretin drug interaction due to evidence of both drugs having affinity for P-glycoprotein.The study has three different objective namely to assess apparent permeability coefficient of cyclosporine in presence of acitretin by non-everted sac technique, to study the intestinal permeation and absorption kinetics of cyclosporine in presence of acitretin by single pass intestinal perfusion (SPIP) technique and to study the influence of acitretin on oral bioavailability of cyclosporine in Wistar rats.The result of ex vivo, in situ and in vivo study showed that cyclosporine level increased in a time dependent manner. As the dose of acitretin increases the cyclosporine concentration in all three methods tend to increase and was statistically significant. The improvement in absorption of cyclosporine may be due to the inhibition of P-glycoprotein transporter in the intestine by acitretin. Thus acitretin may enhance the oral pharmacokinetics of cyclosporine. Hence this combination may require close monitoring for better therapeutic outcome. Our study confirmed the inhibitory role of acitretin on P-glycoprotein leading to increase concentration of cyclosporine.

Intestinal absorption properties of ponicidin by single pass perfusion model in rats

To determine the absorption properties and study the intestinal absorption kinetics of poncidin in rats. In situ single pass perfusion model was combined with High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS/MS) method to investigate the intestinal absorption characteristics and calculate absorption parameters with aspects of drug absorption, concentration and perfusion medium. The absorption of poncidin under acid condition at pH 6.5 was more stable, where intestinal enzymes showed little influence on metabolism, and the absorption was significantly higher than that in pH alkaline condition at pH 8.0 (P<0.05). Drug concentrations had no significant influence on absorption rate constant of the same intestinal segment Ka and apparent permeability coefficient Papp values of poncidin. Different concentrations of poncidin showed no significant differences in the Ka and Papp values among duodenum, jejunum and colon, but the values were significantly lower than ileum absorption parameters, with significant differences (P<0.05). There was no significant effect of verapamil on intestinal absorption of poncidin. The results showed that poncidin could be absorbed at all the studied intestinal segments while ileum seemed to be the best absorption segment in the concentration range of 10-1 000 μg·L⁻¹. The absorption was characterized by a linear dynamic process of passive transport, without absorption saturation. Weak acid environment was helpful for the intestinal absorption of poncidin, and ponicidin was not a substrate of P-glycoprotein (P-gp).

Dietary lipid structure in early life does not program fat absorption in later life

Objectives and studyPreviously, we reported that feeding mice in early life with the experimental infant milk formula Nuturis® (eIMF) with a lipid structure more similar to human milk, i.e. with large (3–5 μm) lipid globules coated with milk phospholipids, resulted in a lower body weight and fat mass gain when challenged with a Western style diet later in life, compared to standard, control IMF (cIMF; Ped Res 72:362; 2012). The mechanism by which eIMF exerts this effect has remained unclear. It is known from literature that lipid uptake kinetics can be important, for example by determining the metabolic fate of absorbed lipids (storage versus oxidation). In this study, we tested the hypothesis that eIMF feeding in early life permanently affects the kinetics of fat absorption in mice.MethodsWe fed male, pair‐housed C57BL/6JOlaHsd mice a rodent diet comprising cIMF or eIMF from postnatal day 16 to 42, followed by 3 weeks of a regular rodent diet (AIN‐93G). At postnatal day 63, upon intraperitoneal injection of the lipoprotein lipase inhibitor poloxamer‐407, fasting mice were administered a lipid bolus containing labeled fat (2H‐oleic acid and tri‐1‐13C‐olein) by gavage. We analyzed plasma lipids and appearance of 13C‐ and 2H‐labeled lipids in blood samples taken at 0, 1, 2, 3 and 5 h after administration using gas chromatography‐mass spectrometry. Values are given in means ± SD.ResultsIn the eIMF and cIMF groups total plasma fatty acids/acyl chains increased similarly over the 5h course of the experiment: from 9±3 to 99±41 mM in cIMF and from 9±4 to 82±36 mM in eIMF, resulting in similar areas under the curve: 252±91 and 221±81 mM·h, respectively. Total plasma fatty acids/acyl chain increase rate between 1 and 3 h after gavage was 22±9 and 20±7 mM·h−1 for cIMF and eIMF, respectively, indicating similar uptake rates from the intestine. The plasma appearances of 2H‐ and 13C‐oleic acid were similar within and between groups. Interestingly, the plasma fat uptake kinetics between the two mice housed in pairs varied by at least a factor two in 10 out of 11 pairs, irrespective of being fed cIMF or eIMF in early life (p&lt;0.001).ConclusionOur data in mice indicate that exposure early in life to dietary fat in the form of larger lipid globules covered with milk phospholipids (Nuturis®) does not affect the kinetics of intestinal fat digestion and absorption later in life. The twofold difference found in fat uptake kinetics between pair‐housed mice now warrants experiments to address whether this translates into different metabolic profiles and sensitivities later in life.Support or Funding InformationDisclosure of interests: The present study was funded by Nutricia Research. BJMvdH is employed by Nutricia Research. HJV is a consultant for Nutricia Research outside the submitted work, for which his institution is financially compensated.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The Importance of Wireless Capsule Endoscopy for Research into the Intestin al Absorption Window of 5-Aminosalicylic Acid in Experimental Pigs.

Absorption windows in particular segments of the small intestine can contribute to the development of orally administered drug formulations and can limit the bioavailability of released compounds. The aim of this study was to evaluate use of wireless capsule enteroscopy regarding the disintegration kinetic process of tablets in the small intestine and its comparison with the levels of the model drug (5- aminosalicylic acid; 5-ASA), and its majority metabolite (N-acetyl-5-aminosalicylic acid; N-acetyl-5-ASA) in blood plasma. Tablets were endoscopically introduced into the duodenum and their disintegration was monitored using wireless capsule enteroscopy in anaesthetised pigs. In parallel, blood plasma time profiles of the model drug (5-ASA) released from tablets and its metabolite (N-acetyl-5-ASA) were detected. The disintegration of tablets was evident in the proximal jejunum (until the 90-minute mark) and culminated at the 3rd hour. The maximum plasmatic concentration of 5-ASA was reached at the 3rd hour and in the case of its metabolite (N-acetyl-5-ASA) at the 4th hour. The study demonstrated the advantage of combination of wireless capsule enteroscopy and bioanalytical determination of pharmacokinetic parameters in an animal experiment to localise the disintegration site of solid dosage form and following kinetics of intestinal absorption of the released active agent.

In vivo intestinal absorption characteristics of phloridzin in rats

To study the in vivo intestinal absorption kinetics of phloridzin in rats. The absorption of phloridzin in the small intestines and colon of rats was investigated using an in vivo single-pass perfusion method and the drug concentration was measured by HPLC. The effects on intestinal absorption of different drug concentration and P-glycoprotein (P-gp) inhibitor were conducted. The results showed that the phloridzin could be absorbed in whole intestine, but more fully in the jejunum and colon segment,poorly absorbed in the duodenum and ileum. The absorption rate constant (Ka) and the apparent absorption coefficient（Papp）of phloridzin decreased following the sequence of jejunum> colon > duodenum > ileum. Absorption parameters of phloridzin had no significant difference at different concentration (5.14, 10.28, 20.56 mg•L⁻¹) . The saturate phenomena was not observed under the test range of drug concentration, and the absorption mechanism may be the passive diffusion transport.There had a significant difference in Ka and Papp values between P-gp inhibitor and no P-gp inhibitor groups. Phloridzin may be the substrate of P-gp.

Milk Polar Lipids Affect In Vitro Digestive Lipolysis and Postprandial Lipid Metabolism in Mice1–3

Background: Polar lipid (PL) emulsifiers such as milk PLs (MPLs) may affect digestion and subsequent lipid metabolism, but focused studies on postprandial lipemia are lacking.Objective: We evaluated the impact of MPLs on postprandial lipemia in mice and on lipid digestion in vitro.Methods: Female Swiss mice were gavaged with 150 μL of an oil-in-water emulsion stabilized with 5.7 mg of either MPLs or soybean PLs (SPLs) and killed after 1, 2, or 4 h. Plasma lipids were quantified and in the small intestine, gene expression was analyzed by reverse transcriptase–quantitative polymerase chain reaction. Emulsions were lipolyzed in vitro using a static human digestion model; triglyceride (TG) disappearance was followed by thin-layer chromatography.Results: In mice, after 1 h, plasma TGs tended to be higher in the MPL group than in the SPL group (141 μg/mL vs. 90 μg/mL; P = 0.07) and nonesterified fatty acids (NEFAs) were significantly higher (64 μg/mL vs. 44 μg/mL; P < 0.05). The opposite was observed after 4 h with lower TGs (21 μg/mL vs. 35 μg/mL; P < 0.01) and NEFAs (20 μg/mL vs. 32 μg/mL; P < 0.01) in the MPL group compared with the SPL group. This was associated at 4 h with a lower gene expression of apolipoprotein B (Apob) and Secretion Associated, Ras related GTPase 1 gene homolog B (Sar1b), in the duodenum of MPL mice compared with SPL mice (P < 0.05). In vitro, during the intestinal phase, TGs were hydrolyzed more in the MPL emulsion than in the SPL emulsion (decremental AUCs were 1750%/min vs. 180%/min; P < 0.01). MPLs enhance lipid intestinal hydrolysis and promote more rapid intestinal lipid absorption and sharper kinetics of lipemia.Conclusions: Postprandial lipemia in mice can be modulated by emulsifying with MPLs compared with SPLs, partly through differences in chylomicron assembly, and TG hydrolysis rate as observed in vitro. MPLs may thereby contribute to the long-term regulation of lipid metabolism.

Rat intestine absorption kinetics study on cucurbitacin B-sodium deoxycholate/ phospholipid mixed nanomicelles with in vitro everted gut sacs model

To investigate the absorption kinetics of Cu B-SDC/PLC-MMs in rat different intestinal segments and compared with the absorption of Cu B suspension. The in vitro everted gut sacs model was established to study the absorption characteristics of Cu B-SDC/ PLC-MMs in rat duodenum, jejunum, ileum and colon, and the content of cucurbitacin B was detected by HPLC method, and the effects of concentrations on intestinal absorption were evaluated as well. The results showed that the absorption of Cu B-SDC/PLC-MMs was linearity at different intestine segment and different concentrations (R2 > 0.9), which was consistent with zero order rate process. The Ka of different intestine segments showed a concentration-dependent increasing along with the raised concentration of Cu B-SDC/ PLC-MMs, indicating that it was likely to be a mechanism of passive absorption. The best absorption site of Cu B-SDC/PLC-MMs was ileum, and its absorptions in different intestinal segments were superior to cucurbitacin B suspension. SDC/PLC-MMs could significantly enhance the intestinal absorption of cucurbitacin B, and the study of intestinal absorption kinetics of Cu B-SDC/PLC-MMs had gave a support to its further reasonable solidfication.

Personalized metabolic profile estimations using oral glucose tolerance tests

Background & ObjectivesOral glucose tolerance tests (OGTTs) are used commonly to diagnose diabetes mellitus (DM). However, blood glucose data and the changes in insulin induced by OGTTs contain information regarding intestinal absorption, hepatic control of glucose and insulin, pancreatic insulin secretion and peripheral tissue glucose and insulin control. Therefore, an appropriate dynamic model could reveal the above information from OGTT data. MethodsWe developed an OGTT model containing five compartments for insulin dynamics and two compartments for glucose dynamics based on previous reports. Anthropometric data of individuals were used to assume the cardiac output. Simplex and Levenberg–Marquardt algorithms were then used to fit the data obtained from 42 normal subjects (24 males and 20 females) and eight subjects with DM. ResultsWe found clear gender differences in the intestinal glucose absorption kinetics, glucose sensitivity in the pancreas, maximal insulin production capacity and endogenous glucose production. There were also differences between normal and DM subjects. For example, pancreatic and liver dysfunctions were evident in DM cases. The differences between normal and DM subjects in glucose and insulin dynamics in the pancreas, liver and peripheral tissues, such as insulin resistance, insulin secretion and the relative roles of glucose disposal in each organ, were demonstrated clearly and quantitatively in a time-dependent manner. ConclusionThis study revealed the quantitative dynamic interaction between glucose and insulin using OGTT data and revealed organ function during the OGTT. Using this approach, we identified the dysfunctional organs for glucose and insulin regulation. Data produced using this model will allow a personalized and targeted approach for health issues related to glucose and insulin.

Effects of fructus psoraleae extract on the intestinal absorption kinetics of geniposide and geniposidic acid in rat.

Cortex Eucommia has been used as a kidney-tonifying herbal medicine with a long history of compatibility with Fructus Psoraleae. Geniposide (GP) and geniposidic acid (GPA) are the two main chemical components in Cortex Eucommia. In the present study, the effects of Fructus Psoraleae extract (FPE) on intestinal absorption kinetics of GP and GPA in rat were investigated. Twenty four male Sprague-Dawley rats were randomly assigned into four groups which were treated with GP, GPA, GP mixed with FPE and GPA mixed with FPE, respectively, by in situ intestinal perfusion for 3 h. The samples of intestinal perfusion solutions were collected every 30 min, and analyzed by ultra high performance liquid chromatography (UPLC). The curves of time and residual quantities of GP and GPA (lnx) in the intestinal perfusion solution and the cumulative absorption rate were obtained. The results showed that FPE exhibited different effects on the intestinal absorption of GP and GPA in rat: it increased the intestinal absorption of GP (p < 0.05), while demonstrated no significant effect on the absorption of GPA.

Study on intestinal absorption kinetics of apigenin in rats

To establish an in situ single-way intestinal perfusion model, in order to study the intestinal absorption kinetics of AP. The concentration of AP in the perfusate was determined by HLPC. The results showed different AP concentrations in all intestinal segments, with the fastest absorption rate in duodenum, which was followed by jejunum, ileum and colon. In general, the constant absorption rate (Ka) of AP in duodenum and jejunum first increased and then decreased with the rise in drug concentration (P <0. 05); the absorption mechanism may be related to active transport and facilitated diffusion factors. The constant absorption rate (Ka) of AP in ileum and colon generally kept unchanged with the rise diffusion in drug concentration, the absorption mechanism may be related to passive.

Study on in situ intestinal absorption of baicalin contained in Tiangou Jiangya capsules

To study in situ intestinal absorption kinetics of baicalin contained in Tiangou Jiangya capsules, and the effect of different intestinal segments, pH value, drug concentration and P-gp inhibitor on the absorption. The in situ intestinal perfusion test was adopted, and HPLC method was used to determine the content of baicalin in samples at different time points. Ultra-violet (UV) spectrophotometry was used to determine the content of phenol red in samples at different time points. When pH value was at 5. 0, 6. 5, 7. 4, the absorption of baicalin was not impacted. P-gp inhibitor verapamil could enhance the absorption of baicalin. When the quality concentration of the test solution ranged between 5-20 g L -1 , the linearity of the absorption amount of baicalin increased. The absorption kinetic equation of baicalin was Y = -0. 073 7X +0. 118 7 (r = 0. 994 8) , K. 0. 073 7 h -1 , t1/2 9. 40 h. Baicalin is mainly absorbed in colon. The absorption of baicalin shows the first-order kinetics process, with the absorption mechanism of passive diffusion. Baicalin is a substrate for P-gp.

Role of glucose transporters in the intestinal absorption of gastrodin, a highly water-soluble drug with good oral bioavailability

Gastrodin, a sedative drug, is a highly water-soluble phenolic glucoside with poor liposolubility but exhibits good oral bioavailability. The current study aims to investigate whether glucose transporters (GLTs) are involved in the intestinal absorption of gastrodin. The intestinal absorption kinetics of gastrodin was determined using the rat everted gut sac model, the Caco-2 cell culture model and the perfused rat intestinal model. In vivo pharmacokinetic studies using diabetic rats with high GLT expression were performed. Saturable intestinal absorption of gastrodin was observed in rat everted gut sacs. The apparent permeability (Papp) of gastrodin from the apical (A) to basolateral (B) side in Caco-2 cells was two-fold higher than that from B to A. Glucose or phlorizin, a sodium-dependent GLT (SGLT) inhibitor, reduced the absorption rates of gastrodin from perfused rat intestines. In vivo pharmacokinetic studies showed that the time of maximum plasma gastrodin concentration (Tmax) was prolonged from 28 to 72 min when orally co-administered with four times higher dose of glucose. However, the Tmax of gastrodin in diabetic rats was significantly lowered to 20 min because of the high intestinal SGLT1 level. In conclusion, our findings indicate that SGLT1 can facilitate the intestinal absorption of gastrodin.

Study on intestinal absorption kinetics of gambogic acid in rats

To investigate the intestinal absorption kinetics of gambogic acid (GA) in rats. In situ single-way intestinal perfusion model was established to study the intestinal absorption kinetics of GA in different absorption segments, and the concentration of GA in the perfusate was determined by HPLC. The effect of drug concentrations on intestinal absorption was also detected. GA showed a higher absorption rate than other intestinal segments (P < 0.05) and kept unchanged in duodenum after addition in drug concentration. GA can be absorbed in all intestinal segments in rats with the higher absorption rate in duodenum. Its mechanism is passive diffusion.

Comparison of the intestinal absorption and bioavailability of γ‐tocotrienol and α‐tocopherol: in vitro, in situ and in vivo studies

The aim of this work was to compare the intestinal absorption kinetics and the bioavailability of γ-tocotrienol (γ-T3) and α-tocopherol (α-Tph) administered separately as oil solutions to rats in vivo. Also, to explain the significant difference in the oral bioavailability of the compounds: (1) the release profiles using the dynamic in vitro lipolysis model, (2) the intestinal permeability and (3) carrier-mediated uptake by Niemann-Pick C1-like 1 (NPC1L1) transporter were examined. Absolute bioavailability studies were conducted after oral administration of γ-T3 or α-Tph prepared in corn oil to rats. In situ rat intestinal perfusion with ezetimibe (a NPC1L1 inhibitor) was performed to compare intestinal permeability. The in vitro interaction kinetics with NPC1L1 was examined in NPC1L1 transfected cells. While the in vitro release studies demonstrated a significantly higher release rate of γ-T3 in the aqueous phase, the oral bioavailability of α-Tph (36%) was significantly higher than γ-T3 (9%). Consequent in situ studies revealed significantly higher intestinal permeability for α-Tph compared with γ-T3 in rats. Moreover, the NPC1L1 kinetic studies demonstrated higher Vmax and Km values for α-Tph compared with γ-T3. Collectively, these results indicate that intestinal permeability is the main contributing factor for the higher bioavailability of α-Tph. Also, these results emphasize the potentially important role of intestinal permeability in the bioavailability of γ-T3, suggesting that enhancing its permeability would increase its oral bioavailability.

Study on intestinal absorption kinetics of syringopicroside in rats

To study the intestinal absorption mechanism of traditional Chinese medicine monomer syringopicroside in rats. The in situ rat single-pass intestinal perfusion model was established to detect the concentration of syringopicroside by HPLC. The absorption at different intestine segments in rat and the influence of concentration, pH and P-glycoprotein inhibitors of the drug solution on the absorption of syringopicroside were also observed. The absorption rate constant (K,) of syringopicroside at duodenum, jejunum, ileum, and colon were 0.00255, 0.00630, 0.00900, 0.00799 min- , respectively; Ka from intestine at syringopicroside concentration of 0.090, 0.180, 0.360 g x L(-1) were 0.00370, 0.00708, 0.00694 min(-1), respectively; and Ka at pH of 7.4, 6.8 and 5.0 were 0.00733, 0.00747, 0.00362 min(-1), respectively. P-glycoprotein inhibitor on the intestinal absorption of syringopicroside showed significant influence (P < 0.05). Syringopicroside is well absorbed at the lower small intestine. When the drug concentration is low, the absorption rate constant is low, where as Ka increases at medium and high concentrations; the Ka is low at pH 5.0 and increases at pH 6.8 and pH 7.4. Syringopicroside is proved to be a substrate of P-glycoprotein.

Glycerolipid Acyltransferases in Triglyceride Metabolism and Energy Homeostasis-Potential as Drug Targets

Glycerolipid acyltransfereases play important roles in physiological and pathophysiological processes of triglyceride (TAG) metabolism and energy balance. Glycerol-3-phosphate acyltransferases (GPATs) are key enzymes in the triglyceride biosynthetic pathway. In addition to the mitochondrial GPAT1 that was first cloned and studied, novel microsomal enzyme isoforms have been discovered in recent years. The potential function of one of the GPATs, GPAT4, was studied in GPAT4 deficient mice that suggested its role in TAG synthesis in multiple tissues. Monoacylglycerol and diacylglycerol acyltransferases (MGAT2 and DGAT1) are important enzymes involved in intestinal triglyceride absorption, and studies in recent years from knockout mice have revealed their important role in whole body energy metabolism through changes in intestinal TAG absorption kinetics. Both MGAT2 and DGAT1 mice are resistant to dietinduced obesity and have improved insulin sensitivity and hepatic TAG accumulation. These data suggest that these enzymes are intimately involved in TAG metabolism and whole body energy homeostasis and that inhibition of these enzymes may provide therapeutic benefits for metabolic disorders such as obesity, metabolic syndrome, and type 2 diabetes.

Study on in situ intestinal absorption of active ingredients in Shuanghuanglian oral liquid in rats

To study the intestinal absorption kinetics characteristic of the main four active ingredients in Shuanghuanglian oral liquid (SHL) and to investigate the influence of herbal compatibility in SHL on absorption of main effective ingredients. The in situ rat circulation model was used to investigate the concentration change differences of the four active components in SHL during perfusion. The absorption quantity of different concentrations of baicalin, chlorogenic acid, phillyrin and forsythoside A ranging from 40-160, 6-24, 3-12, 2.6-10.4 mg x L(-1) respectively was linear with concentration and showed no saturation at high concentration. The absorption rate constant K(a) and the hourly absorption percentages A were essentially unchanged. The pH changing from 5.0-7.43 had little influence on the absorption of phillyrin except baicalin, chlorogenic acid and forsythoside A. The calculated K(a) and A of the four active ingredients had no significant differences from that obtained after perfusing via duodenum, jejunum, ileum and colon; The calculated K(a) and A of baicalin in Scutellariae Radix (SR), chlorogenic acid in Lonicerae Japonicae Flos (LJF) and phillyrin in Forsythiae Fructus (FF) had no significant differences compared with that in SHL, but the calculated K(a) and A of forsythoside A in FF were obviously superior to that in SHL. The intestinal absorption of the four active ingredients in SHL was mainly passive diffusion and had no difference in different segments of rat intestine; the compatibility of SHL compounds changed the absorption of forsythoside A in FF obviously.