Vitamin A status assessment in rats with (13)C(4)-retinyl acetate and gas chromatography/combustion/isotope ratio mass spectrometry.
Vitamin A assessment methods that indirectly determine liver reserves are still in development. The deuterated vitamin A assay has been successfully applied in several population groups, but large doses of vitamin A must be used and the gas chromatography/mass spectrometry analysis is not very sensitive. Therefore, 10,11,14,15-(13)C(4)-retinyl acetate was synthesized using a modified Wittig-Horner procedure. Thereafter, female Sprague-Dawley rats (n = 47) were fed a vitamin A-deficient diet and divided into three groups: low (L), moderate (M) and high (H) vitamin A. Groups L, M and H were supplemented with 35, 70 and 350 nmol of unlabeled retinyl acetate/d for 17 d. On d 18, three rats from each group were killed to determine baseline (13)C levels. Serum was prepared, and livers were collected and stored at -70 degrees C until analyzed with HPLC and gas chromatography/combustion/isotope ratio mass spectrometry. The remaining rats were supplemented with 52 nmol of (13)C(4)-retinyl acetate. Rats were killed on d 1, 2, 4 and 10. The calculated and measured values of total body reserves (TBR) of vitamin A were within 7% of each other overall, and the relationship was linear (r = 0.98, P < 0.0001). The calculated mean TBR were 0.49 +/- 0.03, 0.82 +/- 0.007 and 3.72 +/- 0.40 micromol, and the measured mean TBR were 0.50 +/- 0.045, 0.69 +/- 0.10 and 3.6 +/- 0.29 micromol for groups L, M and H, respectively. In contrast, serum retinol concentrations did not show a difference among the dietary groups: 1.32 +/- 0.14, 1.35 +/- 0.17 and 1.28 +/- 0.15 micromol/L for groups L, M and H, respectively (P = 0.25). In conclusion, this method offers more sensitivity than traditional methods and may be applicable to human vitamin A status assessment when TBR estimations are desired.
Tanumihardjo
S A
SA
Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706-1571, USA.
D000276:Adjuvants, Immunologic / Q000138:chemical synthesis / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004032:Diet; D004224:Diterpenes; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D008099:Liver / Q000378:metabolism; D009752:Nutritional Status; D051381:Rats; D017207:Rats, Sprague-Dawley; D000084562:Retinyl Esters; D014801:Vitamin A / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000138:chemical synthesis / Q000378:metabolism*; D014802:Vitamin A Deficiency / Q000097:blood / Q000378:metabolism*
D000276:Adjuvants, Immunologic; D004224:Diterpenes; D000084562:Retinyl Esters; D014801:Vitamin A; C009166:retinol acetate