TABLE 4.
Fractional turnover of chylomicron- and RBP-derived retinol in organs of control and VA- and VARA-supplemented neonatal rat pups dosed orally with [3H]retinol on postnatal day 41
| Fractional transfer coefficients [L(I,J)], fraction of organ retinol transferred/d | ||||||
|---|---|---|---|---|---|---|
| Turnover of chylomicron-derived retinol2 | Turnover of RBP-derived retinol2 | |||||
| Organ | Control group | VA group | VARA group | Control group | VA group | VARA group |
| Stomach | 5.8 ± 0.2a | 6.2 ± 0.5a,b | 5.0 ± 0.1b | 6.4 ± 3.0 | 79.5 ± 51.5 | 0.8 ± 0.3 |
| Intestines | 0.3 ± 0.0a | 0.2 ± 0.0a | 7.9 ± 0.3b | 0.0 ± 0.0a | 0.0 ± 0.0a | 0.7 ± 0.0b |
| Liver | 0.1 ± 0.3a | 1.4 ± 0.1b | 0.2 ± 0.0a | 0.2 ± 0.1a | 0.1 ± 0.0a | 0.4 ± 0.0b |
| Lungs | 0.8 ± 0.5a | 37.4 ± 4.6b | 0.7 ± 0.0a | 0.2 ± 0.1a | 2.0 ± 0.2b | 0.1 ± 0.0a |
| Kidneys | 4.1 ± 0.6a | 21.2 ± 3.6b | 0.1 ± 0.0c | 6.1 ± 1.1a | 9.4 ± 0.7b | 1.8 ± 0.1c |
| Carcass | 26.2 ± 2.1a | 88.7 ± 10.8b | 5.8 ± 0.1c | 1.1 ± 0.0a | 2.8 ± 0.1b | 0.3 ± 0.0c |
1
Values are means ± SEMs. Means within a row without a common superscript letter differ, P < 0.05 (ANOVA). RBP, retinol-binding protein; VA, vitamin A; VARA, vitamin A combined with retinoic acid.
2
Turnover included both retinol released back to plasma and retinol metabolized irreversibly in an organ, due to an assumption inherent in uncoupling the organs from the rest of the system to model them individually.