Regional Difference in P-glycoprotein Punction in Rat Intestine

doi:10.2133/dmpk.20.100

Drug Metabolism and Pharmacokinetics

Volume 20, Issue 2, 2005, Pages 100-106

https://doi.org/10.2133/dmpk.20.100 Get rights and content

Summary:

It has been reported that inhibition of the P-glycoprotein (P-gp) results in the improved absorption of P-gp substrate in the intestinal tract. In fact, the increased permeability of P-gp substrate across the intestinal epithelium was observed following inhibition of P-gp in in vitro experiments. To develop the formulation containing P-gp inhibitor and P-gp substrate for practical use, it is necessary to know whether the results obtained in the in vitro experiments are reproducible at whole body level. It is also important to find out the regional difference of the P-gp activity in the intestinal tract. In this study, we examined whether verapamil, a specific inhibitor of P-gp, improves the absorption of rhodaminel23 (Rho123), a substrate of P-gp, from the jejunum, ileum, and colon of rats using the in situ loop method. The water content in the loop decreased during the experiment, resulting in a significant change of the Rho123 concentration in the loop. Thus, to accurately determine the absorption rate of Rho123, it was necessary to measure the water movement. It was found that there was a regional difference in the water movement, i.e., greatest in colon, followed by ileum. Verapamil did not change the water movement in any intestinal regions. When the concentration of Rho123 in the loop was corrected by water movement, the Rho123 clearance was in the order of ileum (1.15 μL/min/cm), colon (0.83 μL/min/cm) and jejunum (0.47 μL/min/cm). In the presence of verapamil, the Rho123 clearance was significantly increased at jejunum and ileum but not in colon (ileum: 2.08 μL/min/cm, colon: 1.14 μL/min/cm, jejunum: 1.28 μL/ min/cm). These results suggest that P-gp inhibits the drug absorption in jejunum and ileum. From these results, it is possible to evaluate the role of P-gp and its regional difference in the in situ experiments. In particular, the inhibition of P-gp results in an increase in absorption of the P-gp substrate limited to jejunum and ileum.

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There are more references available in the full text version of this article.

Cited by (22)

Potential of alisols as cancer therapeutic agents: Investigating molecular mechanisms, pharmacokinetics and metabolism
2023, Biomedicine and Pharmacotherapy
Albeit remarkable achievements in anti-cancer endeavors, the prevention and treatment of cancer remain unresolved challenges. Hence, there is an urgent need to explore new and efficacious natural compounds with potential anti-cancer therapeutic agents. One such group of compounds is alisols, tetracyclic triterpene alcohols extracted from alisma orientale. Alisols play a significant role in cancer therapy as they can suppress cancer cell proliferation and migration by regulating signaling pathways such as mTOR, Bax/Bcl-2, CHOP, caspase, NF-kB and IRE1. Pharmacokinetic studies showed that alisols can be absorbed entirely, rapidly, and evenly distributed in vivo. Moreover, alisols are low in toxicity and relatively safe to take. Remarkably, each alisol can be converted into many compounds with different pathways to their anti-cancer effects in the body. Thus, alisols are regarded as promising anti-cancer agents with minimal side effects and low drug resistance. This review will examine and discuss alisols' anti-cancer molecular mechanism, pharmacokinetics and metabolism. Based on a comprehensive analysis of nearly 20 years of research, we evaluate the therapeutic potential of alisols for various types of cancer and offer insights and strategies for developing new cancer treatments.
P-glycoprotein activation by 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) in rat distal ileum: ex vivo and in vivo studies
2020, Toxicology and Applied Pharmacology
Citation Excerpt :
As such, the activation effect was observed shortly after administration and, therefore, unaffected by the potential toxicity of the compound at this dose (30 mg/kg b.w.) (Rocha-Pereira et al., 2019). It is known that there is a regional difference of P-gp activity in the intestinal tract and that the expression levels of P-gp greatly vary along the small intestine, being the highest in the distal ileum and the lowest in the proximal portion (Doherty and Charman, 2002; Iida et al., 2005; Li et al., 2015). For that reason, we decided to start the study of the effects of TX5 on P-gp expression levels using the portion of the ileum where the expression pattern of the transporter is the most expressive.
In vitro studies showed that 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) increases P-glycoprotein (P-gp) expression and activity in Caco-2 cells, preventing xenobiotic toxicity. The present study aimed at investigating TX5 effects on P-gp expression/activity using Wistar Han rats: a) in vivo, evaluating intestinal P-gp activity; b) ex vivo, evaluating P-gp expression in ileum brush border membranes (BBM) and P-gp activity in everted intestinal sacs; c) ex vivo, evaluating P-gp activity in everted intestinal sacs of the distal and proximal ileum. TX5 (30 mg/kg, b.w.), gavage, activated P-gp in vivo, given the significant decrease in the AUC of digoxin (0.25 mg/kg, b.w.). The efflux of rhodamine 123 (300 μM), a P-gp fluorescent substrate, significantly increased in TX5-treated everted sacs from the distal portion of the rat ileum, when P-gp activity was evaluated in the presence of TX5 (20 μM), an effect abolished by the P-gp inhibitor verapamil (100 μM). No increases on P-gp expression or activity were found in TX5-treated BBM of the distal ileum and everted distal sacs, respectively, 24 h after TX5 (10 mg/kg, b.w.) administration. In vivo, no differences were found on digoxin portal concentration between control (digoxin 0.025 mg/kg, b.w., intraduodenal) and TX5-treated (digoxin+TX5 20 μM, intraduodenal) rats. The observed discrepancies in digoxin results can be related to differences in TX5 dose administered and used methodologies. Thus, the results show that TX5 activates P-gp at the distal portion of the rat ileum, and, at the higher dose tested (30 mg/kg, b.w.), seems to modulate in vivo the AUC of P-gp substrates.
Evaluation of alkylmaltosides as intestinal permeation enhancers: Comparison between rat intestinal mucosal sheets and Caco-2 monolayers
2012, European Journal of Pharmaceutical Sciences
Citation Excerpt :
These authors have argued that P-gp plays a minimal role in reducing intestinal permeation of highly permeable molecules, and this is consistent with the very high absorptive and secretory Papp values found for [3H]-propranolol. Furthermore, in rat in situ instillations, the potent P-gp substrate rhodamine-123 was not subject to rat colonic P-gp mediated efflux when corrected for water transport in that region as its absorptive flux was not increased by the P-gp inhibitor, verapamil (Iida et al., 2005). In sum, high P-gp expression in rat colon does not necessarily translate to polarised flux for a well-absorbed soluble P-gp substrate and thus [3H]-propranolol would appear to be a valid marker for passive transcellular permeation.
Alkylmaltosides are a class of non-ionic surfactant currently in clinical trials to improve nasal permeation of peptide drugs, however few studies have detailed their potential effects on intestinal permeation enhancement. Tetradecyl maltoside (TDM, C₁₄), was examined in Caco-2 monolayers and in isolated rat jejunal and colonic mucosae mounted in Ussing chambers. Dodecyl maltoside (DDM, C₁₂) was examined in mucosae. Parameters measured included critical micelle concentration (CMC), transepithelial electrical resistance (TEER), and apparent permeability coefficients (P_app) of paracellular and transcellular flux markers. TDM and DDM decreased TEER and increased the P_app of [¹⁴C]-mannitol and FD-4 across Caco-2 monolayers and colonic mucosae in the concentration range of 0.01–0.1% w/v, concentrations much higher than the CMC. Remarkably, neither agent had any effect on the TEER or fluxes of jejunal mucosae. Histopathology, cell death assays (MTT and LDH) and sub-lethal high content cytotoxicity analyses (HCA) were carried out with TDM. Exposure of colonic mucosae to high concentrations of TDM had no major effects on gross histology and ion transport function was retained. In Caco-2, HCA data at sub-lethal concentrations of TDM was consistent with the action of a mild non-ionic surfactant. In conclusion, alkylmaltosides are effective non-toxic permeation enhancers in isolated colonic tissue and their inclusion in oral peptide formulations directed to that intestinal region warrants further study.
Suppression of efflux transporters in the intestines of endotoxin-treated rats
2012, International Journal of Pharmaceutics
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).
This article has been retracted at the request of Publisher Drug Metabolism and Disposition.
The authors have plagiarized text of a paper that had already appeared in Drug MetabDispos32 (2004) 20–27 http://dx.doi.org/10.1124/dmd.32.1.20
The integrity of the research findings in the retracted article is undisputed.
The Publisher apologizes for any inconvenience caused.
Suitability of isolated rat jejunum model for demonstration of complete absorption in humans for bcs-based biowaiver request
2012, Journal of Pharmaceutical Sciences
Citation Excerpt :
On the basis of these results, a criterion for P-gp functionality in isolated rat jejunum model is efflux ratio ≥ 1.9. Although the same part of rat jejunum was used in all experiments presented herein, the fluctuation of P-gp efflux most probably originates from intersubject variability in regional dependence expression and functionality of P-gp in rat's intestine.96 In all permeability experiments and particularly in experiments aimed in permeability classification, according to BCS, tissue viability and integrity need to be assured.
The objective of this study was to evaluate the suitability and acceptance criteria of isolated rat jejunum model for Biopharmaceutics Classification System (BCS)—permeability classification. The evaluation followed recommended procedures including investigation of tissue integrity by applying damage triggers (nitrogen gassing, elevated temperature, azide addition), characterization of transporter functionality, and expression and development of correlation between rats' apparent permeability coefficient (P_app) versus humans' and versus oral fraction absorbed (f_a) in humans. Firstly, damage triggers caused a decrease in transepithelial resistance and potential difference and increase in lucifer yellow (LY) and fluorescein isothiocyanate (FITC)–dextran P_app. However, only FITC–dextran P_app's increase was considered significant in all treatment groups, making FITC–dextran a better indicator of jejunum integrity than LY. Secondly, the expression level of selected intestinal transporters highly correlated between rat and human and functionality of P-glycoprotein was confirmed. P_app of investigated drugs correlated with human f_a (R² = 0.85, n = 20) and with human permeability coefficients (R² = 0.86, n = 13). Utility of described model for BCS classification was shown on levetiracetam, where significantly higher permeability of levetiracetam as compared with internal standard metoprolol was determined (t-test, p = 0.005). In conclusion, isolated rat jejunum model is a useful tool not only for mechanistic investigation, but also for permeability classification according to BCS and consequently for BCS-based biowaiver procedures.
Inducible nitric oxide synthase-mediated decrease of intestinal P-glycoprotein expression under streptozotocin-induced diabetic conditions
2010, Life Sciences
P-glycoprotein (P-gp), one of the important drug-efflux pumps, is known to be affected by pathological conditions such as inflammation or infection. Recently, it is reported that high glucose or hyperglycemia can alternate P-gp expression levels at the blood-brain barrier or in the kidney, although the details are still unknown. Here, we analyzed the alteration of intestinal P-gp expression and function in the development of diabetes and elucidated the mechanisms.
Type 1 diabetes was induced in male ddY mice by an i.p. injection of streptozotocin (STZ) (230 mg/kg). We analyzed ileal P-gp expression and function using Western blot analysis and an in situ closed loop method, respectively.
A significant reduction of P-gp expression level in ileum was found 9 days after STZ administration. In contrast, a remarkable decrease in P-gp function was observed on the 3rd and 9th days. Interestingly, nitric oxide synthase (NOS) activity in ilea was significantly increased on the 9th day. The decrease of P-gp expression levels observed on the 9th day was completely suppressed by L-N^G-nitroarginine methyl ester (L-NAME), a broad range NOS inhibitor, or aminoguanidine, a specific inducible NOS (iNOS) inhibitor.
These results indicate the possibility that nitric oxide (NO), produced by iNOS in the ileum, is involved in the reduction of ileal P-gp expression under STZ-induced diabetic conditions.

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Drug Metabolism and Pharmacokinetics

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References (21)

Role of P-glycoprotein as a secretory mechanism in qunidine absorption from rat small intestine

J. Pharm. Sci.

Region-dependent disappearance of vinblastine in rat small intestine and characterization of its P-glycoprotein-mediated efflux system

Eur. J. Pharmaceutical. Sci.

Involvement of intestinal P-glycoprotein in the Restricted absorption of Methylprednisolone from et al. rat small intestine

J. Pharm. Sci.

Intestinal drug efflux: formulation and food effects

Advanced Drug Delivery Reviews

The role of P-glycoprotein in limiting intestinal regional absorption of digoxin in rats

Eur. J. Pharmacol.

Drug absorption I: An in situ rat gut technique yielding realistic absorption rates

J. Pharm. Sci.

Polarized transport of hydrophilic compounds across rat colonic mucosa from serosal to mucosa is temperature dependent

Gastroenterol.

Relevance of the chemical charge of rhodamine dyes to multiple drug resistance

Biochem. Pharmacol.

Rhodamine 123 accumulates extensively in the isolated perfused rat kidney and is secreted by the organic cation system

Eur. J. Pharmacol.

Expression of multidrug-resistance gene in human tumors and tissues

Proc. Natl. Acd. Sci. USA

Cited by (22)

Potential of alisols as cancer therapeutic agents: Investigating molecular mechanisms, pharmacokinetics and metabolism

P-glycoprotein activation by 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) in rat distal ileum: ex vivo and in vivo studies

Evaluation of alkylmaltosides as intestinal permeation enhancers: Comparison between rat intestinal mucosal sheets and Caco-2 monolayers

Suppression of efflux transporters in the intestines of endotoxin-treated rats

Suitability of isolated rat jejunum model for demonstration of complete absorption in humans for bcs-based biowaiver request

Inducible nitric oxide synthase-mediated decrease of intestinal P-glycoprotein expression under streptozotocin-induced diabetic conditions

Regular ArticleRegional Difference in P-glycoprotein Punction in Rat Intestine

Summary:

J. Pharm. Sci.

Eur. J. Pharmaceutical. Sci.

J. Pharm. Sci.

Advanced Drug Delivery Reviews

Eur. J. Pharmacol.

J. Pharm. Sci.

Gastroenterol.

Biochem. Pharmacol.

Eur. J. Pharmacol.

Expression of multidrug-resistance gene in human tumors and tissues

Proc. Natl. Acd. Sci. USA

Regular Article
Regional Difference in P-glycoprotein Punction in Rat Intestine