Summary of carnitine disposition by haplotype After a 12-h fast, blood was drawn from subjects homozygous for either the C/G* haplotype [OCTN1-1507C, OCTN2-(–207G); n = 7] or T/C* haplotype [OCTN1–1507T, OCTN2-(–207C); n = 9] at the OCTN locus. Urine was collected over the next 2 h, and a final blood draw was collected at 2 h after initiating the study. Plasma and urine samples were analyzed for free (nonesterified) carnitine and total (free plus esterified) carnitine as well as creatinine. The mean analyte concentration (from the baseline and 2-h blood draws) for each subject was used in the analysis. Values are shown as mean ± S.D. Differences between haplotype groups were assessed using a two-tailed unpaired t test.
Carnitine | Total Sample | Haplotype | p Value | |||
|---|---|---|---|---|---|---|
| C/G* (n = 7) | T/C* (n = 9) | |||||
| Plasma carnitine levels (μM) | Free | 31.2 ± 5.3 | 32.5 ± 5.9 | 30.2 ± 4.9 | 0.410 | |
| Esters | 8.35 ± 2.45 | 7.90 ± 1.51 | 8.71 ± 3.04 | 0.532 | ||
| Total | 39.6 ± 5.7 | 40.4 ± 6.2 | 38.9 ± 5.6 | 0.622 | ||
| Carnitine CLR (ml/min) | Free | 2.77 ± 2.25 | 3.20 ± 2.97 | 2.44 ± 1.61 | 0.527 | |
| Total | 5.77 ± 3.24 | 5.78 ± 3.58 | 5.76 ± 3.17 | 0.993 | ||
| Creatinine CL (ml/min) |
| 138 ± 34 | 145 ± 40 | 132 ± 30 | 0.478 | |