title: Pharmacokinetics of 125I-GST-TatdMt, a recombinant fusion protein possessing potent anti-obesity activity, after intravenous, nasal, oral, and subcutaneous administration.
abstract: This study first reports the absorption kinetics of GST-TatdMt, a recombinant Tat protein possessing potent anti-obesity activity, in rats after nasal, s.c., and p.o. administration. GST-TatdMt was over-expressed in E. coli, purified, and radioiodinated using the IODO-GEN method. The radioiodinated 125I-GST-TatdMt was administered to rats by nasal, s.c., and oral routes at doses of 7.3 microg (420.7 nCi), 146.5 microg (8413.8 nCi), and 146.5 microg (8413.8 nCi), respectively. For the determination of absolute bioavailability, 125I-GST-TatdMt was also given to rats by i.v. injection (73.2 microg, 4206.9 nCi). Following administration by extravascular routes, the systemic absorption of radioactivity was prolonged, with Cmax being attained within 4.2-8.0 h. The absolute bioavailability calculated as dose-normalized AUC(extravascular)/AUC(i.v.) was 98.0, 75.8, and 87.1% after nasal, s.c., and oral administration, respectively. The majority of administered radioactivity was excreted in urine (57.5-64.7%), with fecal excretion being less (2.5-12.7%). The distribution of 125I-GST-TatdMt to various tissues was also determined at 4 and 72 h after s.c. injection. The findings of this study suggest that this protein may be absorbed into the systemic circulation when given by extravascular administration.
authors.affiliation: College of Pharmacy, Sungkyunkwan University, 300 Cheoncheon-dong, Jangan-gu, Suwon, Kyeonggi-do, 440-746, Republic of Korea.
authors.forename: Beom Soo
authors.initials: BS
authors.lastname: Shin
authors.forename: Chul Hwan
authors.initials: CH
authors.lastname: Kim
authors.forename: Min-Nyung
authors.initials: MN
authors.lastname: Lee
authors.forename: Man-Wook
authors.initials: MW
authors.lastname: Hur
authors.forename: Kang Choon
authors.initials: KC
authors.lastname: Lee
authors.forename: Yu Seok
authors.initials: YS
authors.lastname: Youn
authors.forename: Sun Dong
authors.initials: SD
authors.lastname: Yoo
mesh_terms: D000281:Administration, Intranasal; D000284:Administration, Oral; D000818:Animals; D015696:Gene Products, tat / Q000008:administration & dosage / Q000235:genetics / Q000493:pharmacokinetics*; D005982:Glutathione Transferase / Q000008:administration & dosage / Q000235:genetics / Q000493:pharmacokinetics*; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D007457:Iodine Radioisotopes; D008297:Male; D009765:Obesity / Q000188:drug therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics / Q000493:pharmacokinetics*; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D015696:Gene Products, tat; D007457:Iodine Radioisotopes; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase