Species specificity profiling of rat and human organic cation/carnitine transporter Slc22a5/SLC22A5 (Octn2/OCTN2).
Drug Metab Pharmacokinet
; 32(3): 165-171, 2017 Jun.
Article
in En
| MEDLINE
| ID: mdl-28365301
ABSTRACT
The purpose of this study was to characterize the uptake of carnitine, the physiological substrate, and the uptake of 3-(2,2,2-trimethylhydrazinium)propionate, a consensus substrate by rat Octn2 and human OCTN2 transporters as well as to characterize drug-mediated inhibition of l-carnitine uptake by the rat and human orthologs overexpressed in CHO-K1 cells. l-carnitine and 3-(2,2,2-trimethylhydrazinium)propionate were found to be a lower affinity substrate for rat Octn2 (KM = 32.66 ± 5.11 µM and 23.62 ± 4.99 µM respectively) than for human OCTN2 (KM = 3.08 ± 0.74 µM and 7.98 ± 0.63 µM). The intrinsic clearance (CLint) value for carnitine was higher for the human than for the rat transporter (22.82 ± 5.57 ml/min*mg vs 4.008 ± 0.675 ml/min*mg). For 3-(2,2,2-trimethylhydrazinium)propionate, in contrast, the CLint value for rat Octn2 was higher than for human OCTN2 (323.9 ± 72.8 ml/min*mg vs 65.11 ± 5.33 ml/min*mg). Furthermore, many pharmacologically important drugs were shown to affect l-carnitine transport by Octn2/OCTN2. The correlation between the IC50 datasets for the rat and human transporter resulted in an r value of 0.47 (p > 0.05). However, the greatest difference was less than seven-fold and 13 of 15 compounds yielded a difference less than 3-fold. Thus, the transporters from these two species showed an overlapping but somewhat different substrate and inhibitor specificity.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Carnitine
/
Solute Carrier Family 22 Member 5
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Methylhydrazines
Limits:
Animals
/
Humans
/
Male
Language:
En
Journal:
Drug Metab Pharmacokinet
Journal subject:
FARMACOLOGIA
/
METABOLISMO
Year:
2017
Document type:
Article
Country of publication:
ENGLAND
/
ESCOCIA
/
GB
/
GREAT BRITAIN
/
INGLATERRA
/
REINO UNIDO
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SCOTLAND
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UK
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UNITED KINGDOM