QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Green, M. H. Articles by Green, J. B. Search for Related Content PubMed PubMed Citation Articles by Green, M. H. Articles by Green, J. B.

Vitamin A Intake and Status Influence Retinol Balance, Utilization and Dynamics in Rats^1,2,

Nutrition Department, The Pennsylvania State University, University Park, PA 16802

To study effects of vitamin A status on retinol dynamics, male rats were fed purified diets varying in vitamin A concentration. Group 1 rats had marginal liver vitamin A levels (500 nmol) and were in a slight positive vitamin A balance; Group 2 had similar liver levels but were in a slight negative balance; Group 3 had lower liver levels (370 nmol) and were in a slight negative balance; Group 4 had depleted liver reserves (<10 nmol) and were in vitamin A balance. [³H]Retinollabeled plasma was injected intravenously, and serial plasma samples were collected for 41 d while rats (six per group) consumed 50 nmol retinol/d (Group 1) or 25 nmol/d (Groups 2–4). Plasma retinol was normal in Groups 1–3 (1.9–2.0 µmol/L) and lower in Group 4 (0.96 µmol/L). Plasma tracer data were fit to a three-compartment model. The central plasma retinol compartment (transit time, 1.5–1.7 h) exchanged with a fast turning-over extravascular vitamin A pool (transit time, 3–4.5 h; 40 nmol) and with a larger, slow turning-over extravascular pool (transit time, 5.5–10 d) that was the site of irreversible utilization of vitamin A. Irreversible utilization was 36 nmol/d (Group 1), 29 nmol/d (Groups 2 and 3) and 20 nmol/d (Group 4). The data indicate that in rats with low or marginal vitamin A status, vitamin A intake, vitamin A reserves and plasma retinol concentration all influence vitamin A utilization and other aspects of retinol dynamics.

KEY WORDS: • rats • simulation • modeling • compartmental analysis • vitamin A requirement

¹ Supported by a grant from the U.S. Department of Agriculture (Competitive Research Grant 88-37200-3537).

² The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 USC section 1734 solely to indicate this fact.

³ To whom correspondence should be addressed.

Manuscript received 8 March 1994. Revision accepted 30 August 1994.

This article has been cited by other articles:

				S. H. Gieng, M. H. Green, J. B. Green, and F. J. Rosales Model-based compartmental analysis indicates a reduced mobilization of hepatic vitamin A during inflammation in rats J. Lipid Res., April 1, 2007; 48(4): 904 - 913. [Abstract] [Full Text] [PDF]