TABLE 3. Retinol and retinyl ester levels of embryos from dams maintained on different dietary regimens of vitamin A.

Retinol and retinyl ester levels in embryos collected at 14.5 dpc were determined by reversed-phase HPLC. Embryonic genotype are indicated as follows: WT, wild-type; R^−/−, RBP knockout; L^−/−R^−/−, double knock-out for LRAT and RBP. Three different regimens of maternal dietary vitamin A intake are indicated (see text and Table 1). Retinol, retinyl ester (sum of retinyl linoleate, oleate, palmitate, and stearate), and total retinoid (sum of retinol and retinyl ester) concentrations are expressed as mean ± S.D. Statistical analyses were performed for retinol and retinyl ester levels only, as described under “Experimental Procedures.” n = 3–4 embryos/group. A p < 0.05 was considered statistically significant.

Genotype	Embryonic retinol and retinyl ester levels
	VitA-suff			VitA-def			VitA-exc
	Retinol	Retinyl ester	Total retinoid	Retinol	Retinyl ester	Total retinoid	Retinol	Retinyl ester	Total retinoid
		µg/g			µg/g			µg/g
WT	0.12 + 0.03	0.32 + 0.04	0.44 + 0.06	0.09 + 0.01	0.19 + 0.01a	0.29 + 0.01	0.29 + 0.03a	1.03 + 0.08a	1.25 + 0.11
R−/−	0.05 + 0.01b	0.22 + 0.01b	0.27 + 0.03	0.04 + 0.01b	0.09 + 0.03a,b	0.13 + 0.02	0.12 + 0.03a,b	0.81 + 0.36a	0.93 + 0.39
L −/− R−/−	0.11 ± 0.01c	0.03 ± 0.01b,c	0.14 ± 0.03	0.01 ± 0.01a,b,c	0.03 ± 0.02b,c	0.05 ± 0.02	0.26 ± 0.02a,c	0.03 ± 0.01b,c	0.29 ± 0.03

^ap < 0.05 versus sufficient diet group of the same genotype.

^bp < 0.05 versus WT on the same dietary regimen.

^cp < 0.05 versus R^−/− on the same dietary regimen.