Plasma retinol is a major determinant of vitamin A utilization in rats

Sean K. Kelley, Michael H. Green

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

We studied relationships among vitamin A intake, liver levels of vitamin A, plasma retinol concentrations and the irreversible utilization of vitamin A. To supplement existing data, we first used model-based compartmental analysis to determine vitamin A utilization and other kinetic parameters in male Sprague-Dawley rats that had adequate liver vitamin A stores (~9000 nmol) and were fed a diet containing low levels of vitamin A. Plasma retinol kinetics were monitored for 43 d after administration of [3H]retinol- labeled plasma to rats consuming ~23 (Group 1, n = 6) or ~4.2 (Group 2, n = 6) nmol vitamin A/d. Data for plasma tracer vs. time and for tracer lost irreversibly by the end of the experiment, were fit to a three-compartment model in which plasma retinol exchanges with vitamin A in two kinetically distinct extravascular compartments. Irreversible utilization rates (~41 nmol/d) were similar to those for rats that are in vitamin A balance, suggesting that, when liver vitamin A stores are adequate, utilization rate is not decreased to compensate for a low vitamin A intake. Multiple linear regression analysis was then used to relate these and previously collected data (total, 62 rats) on vitamin A intake (4.2-49 nmol/d), plasma retinol concentration (1.4-2.5 μmol/L) and liver vitamin A level (1.2-11,000 nmol) to vitamin A utilization (disposal rate, 4.2-68 nmol/d). A significant relationship (R(ad)/2= 0.93) was found for the equation [disposal rate (nmol/d) = -0.720 (nmol/d) + 0.844 (d-1) · (plasma retinol; nmol) + 0.00139 (d-1) · (liver vitamin A; nmol) + 0.220 · (vitamin A intake; nmol/d)]. Plasma retinol accounted for 92% of the variability in disposal rate (vs. 5% for liver vitamin A and 3% for vitamin A intake). We conclude that plasma retinol is a main determinant of the irreversible utilization of vitamin A in rats with low to moderate vitamin A intake.

Original languageEnglish (US)
Pages (from-to)1767-1773
Number of pages7
JournalJournal of Nutrition
Volume128
Issue number10
StatePublished - Oct 1 1998

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Vitamin A
Liver

All Science Journal Classification (ASJC) codes

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

Cite this

Kelley, S. K., & Green, M. H. (1998). Plasma retinol is a major determinant of vitamin A utilization in rats. Journal of Nutrition, 128(10), 1767-1773.
Kelley, Sean K. ; Green, Michael H. / Plasma retinol is a major determinant of vitamin A utilization in rats. In: Journal of Nutrition. 1998 ; Vol. 128, No. 10. pp. 1767-1773.
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abstract = "We studied relationships among vitamin A intake, liver levels of vitamin A, plasma retinol concentrations and the irreversible utilization of vitamin A. To supplement existing data, we first used model-based compartmental analysis to determine vitamin A utilization and other kinetic parameters in male Sprague-Dawley rats that had adequate liver vitamin A stores (~9000 nmol) and were fed a diet containing low levels of vitamin A. Plasma retinol kinetics were monitored for 43 d after administration of [3H]retinol- labeled plasma to rats consuming ~23 (Group 1, n = 6) or ~4.2 (Group 2, n = 6) nmol vitamin A/d. Data for plasma tracer vs. time and for tracer lost irreversibly by the end of the experiment, were fit to a three-compartment model in which plasma retinol exchanges with vitamin A in two kinetically distinct extravascular compartments. Irreversible utilization rates (~41 nmol/d) were similar to those for rats that are in vitamin A balance, suggesting that, when liver vitamin A stores are adequate, utilization rate is not decreased to compensate for a low vitamin A intake. Multiple linear regression analysis was then used to relate these and previously collected data (total, 62 rats) on vitamin A intake (4.2-49 nmol/d), plasma retinol concentration (1.4-2.5 μmol/L) and liver vitamin A level (1.2-11,000 nmol) to vitamin A utilization (disposal rate, 4.2-68 nmol/d). A significant relationship (R(ad)/2= 0.93) was found for the equation [disposal rate (nmol/d) = -0.720 (nmol/d) + 0.844 (d-1) · (plasma retinol; nmol) + 0.00139 (d-1) · (liver vitamin A; nmol) + 0.220 · (vitamin A intake; nmol/d)]. Plasma retinol accounted for 92{\%} of the variability in disposal rate (vs. 5{\%} for liver vitamin A and 3{\%} for vitamin A intake). We conclude that plasma retinol is a main determinant of the irreversible utilization of vitamin A in rats with low to moderate vitamin A intake.",
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Kelley, SK & Green, MH 1998, 'Plasma retinol is a major determinant of vitamin A utilization in rats', Journal of Nutrition, vol. 128, no. 10, pp. 1767-1773.

Plasma retinol is a major determinant of vitamin A utilization in rats. / Kelley, Sean K.; Green, Michael H.

In: Journal of Nutrition, Vol. 128, No. 10, 01.10.1998, p. 1767-1773.

Research output: Contribution to journalArticle

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N2 - We studied relationships among vitamin A intake, liver levels of vitamin A, plasma retinol concentrations and the irreversible utilization of vitamin A. To supplement existing data, we first used model-based compartmental analysis to determine vitamin A utilization and other kinetic parameters in male Sprague-Dawley rats that had adequate liver vitamin A stores (~9000 nmol) and were fed a diet containing low levels of vitamin A. Plasma retinol kinetics were monitored for 43 d after administration of [3H]retinol- labeled plasma to rats consuming ~23 (Group 1, n = 6) or ~4.2 (Group 2, n = 6) nmol vitamin A/d. Data for plasma tracer vs. time and for tracer lost irreversibly by the end of the experiment, were fit to a three-compartment model in which plasma retinol exchanges with vitamin A in two kinetically distinct extravascular compartments. Irreversible utilization rates (~41 nmol/d) were similar to those for rats that are in vitamin A balance, suggesting that, when liver vitamin A stores are adequate, utilization rate is not decreased to compensate for a low vitamin A intake. Multiple linear regression analysis was then used to relate these and previously collected data (total, 62 rats) on vitamin A intake (4.2-49 nmol/d), plasma retinol concentration (1.4-2.5 μmol/L) and liver vitamin A level (1.2-11,000 nmol) to vitamin A utilization (disposal rate, 4.2-68 nmol/d). A significant relationship (R(ad)/2= 0.93) was found for the equation [disposal rate (nmol/d) = -0.720 (nmol/d) + 0.844 (d-1) · (plasma retinol; nmol) + 0.00139 (d-1) · (liver vitamin A; nmol) + 0.220 · (vitamin A intake; nmol/d)]. Plasma retinol accounted for 92% of the variability in disposal rate (vs. 5% for liver vitamin A and 3% for vitamin A intake). We conclude that plasma retinol is a main determinant of the irreversible utilization of vitamin A in rats with low to moderate vitamin A intake.

AB - We studied relationships among vitamin A intake, liver levels of vitamin A, plasma retinol concentrations and the irreversible utilization of vitamin A. To supplement existing data, we first used model-based compartmental analysis to determine vitamin A utilization and other kinetic parameters in male Sprague-Dawley rats that had adequate liver vitamin A stores (~9000 nmol) and were fed a diet containing low levels of vitamin A. Plasma retinol kinetics were monitored for 43 d after administration of [3H]retinol- labeled plasma to rats consuming ~23 (Group 1, n = 6) or ~4.2 (Group 2, n = 6) nmol vitamin A/d. Data for plasma tracer vs. time and for tracer lost irreversibly by the end of the experiment, were fit to a three-compartment model in which plasma retinol exchanges with vitamin A in two kinetically distinct extravascular compartments. Irreversible utilization rates (~41 nmol/d) were similar to those for rats that are in vitamin A balance, suggesting that, when liver vitamin A stores are adequate, utilization rate is not decreased to compensate for a low vitamin A intake. Multiple linear regression analysis was then used to relate these and previously collected data (total, 62 rats) on vitamin A intake (4.2-49 nmol/d), plasma retinol concentration (1.4-2.5 μmol/L) and liver vitamin A level (1.2-11,000 nmol) to vitamin A utilization (disposal rate, 4.2-68 nmol/d). A significant relationship (R(ad)/2= 0.93) was found for the equation [disposal rate (nmol/d) = -0.720 (nmol/d) + 0.844 (d-1) · (plasma retinol; nmol) + 0.00139 (d-1) · (liver vitamin A; nmol) + 0.220 · (vitamin A intake; nmol/d)]. Plasma retinol accounted for 92% of the variability in disposal rate (vs. 5% for liver vitamin A and 3% for vitamin A intake). We conclude that plasma retinol is a main determinant of the irreversible utilization of vitamin A in rats with low to moderate vitamin A intake.

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