Farmakologijos esė anglų kalba: ABC transporteriai

P-glycoprotein (P-gp or ABCB1) and breast cancer resistance protein (BCRP or ABCG2) (1) are ATP-binding-cassette (ABC) transporters that export drugs-substrates out of cells, decreasing drug bioavailability, tissue distribution (2), absorption and altering drug elimination (3). Bioavailability is the measure of rate and fraction of the administered dose of a drug that successfully reaches the target site (4), whereas tissue distribution is the degree of absorption of the drug into different tissues from the blood. In various tumours and cancer cell lines, ABC transporters are overexpressed, a phenomenon known as multi-drug resistance (MDR). This overexpression leads to a prolonged illness, high medical costs and high patient mortality rates (5). To solve this problem, pharmacologists created inhibitors for the transporters, geneticists identified certain polymorphisms leading to overexpressed P-gp or BCRP (1) (6), biochemists silenced ABCB1 and ABCG2 genes using the CRISP/Cas9 system and ribonucleic acid (RNA) interference. This essay will focus on how P-gp and BCRP decrease drug bioavailability, tissue distribution and how to reverse it.
The transporters are either full transporters, having 2 transmembrane domains (TMDs) and 2 nucleotide adenosine triphosphate binding domains (NBDs), or half-transporters, having one TMD and one NBD (Fig. 1).
Figure 1. Simplified schematic of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). Each transmembrane domain (TMD) has 6 alpha-helices (ovals) spanning the membrane (7). NBD – nucleotide-binding domain. A – P-gp is full transporter: has two NBDs, one just before the C-terminus of the protein. 1-6 alpha helices form the first transmembrane domain and 7-12 helices form the second transmembrane domain. B – BCRP is a half-transporter: has only one NBD that is just before after the N-terminus; the transmembrane domain is made up of 6 alpha-helices. BCRP N-terminus is closer to the NBD, while P-gp and the majority of ABC transporters have N-terminus closer to the TMD....

Daugiau informacijos...

★ Klientai rekomenduoja

Šį rašto darbą rekomenduoja mūsų klientai. Ką tai reiškia?

Mūsų svetainėje pateikiama dešimtys tūkstančių skirtingų rašto darbų, kuriuos įkėlė daugybė moksleivių ir studentų su skirtingais gabumais. Būtent šis rašto darbas yra patikrintas specialistų ir rekomenduojamas kitų klientų, kurie po atsisiuntimo įvertino šį mokslo darbą teigiamai. Todėl galite būti tikri, kad šis pasirinkimas geriausias!