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The transfer and metabolism of retinol by human placenta was investigated using an in vitro perfusion system with independent maternal and fetal circulations. 3H-retinol bound to albumin added to the maternal perfusate was rapidly taken up and concentrated by the placenta to levels 16.5 +/- 5.28 times the maternal perfusate. Approximately 8% of the retinol retained in the placenta was esterified. No metabolites were detected in the perfusates. Perfusion of placenta with retinol bound to retinol-binding protein (RBP) reduced the placental concentration to 4.4 +/- 1.72 times the maternal concentration and eliminated evidence of metabolism. The transfer rate of RBP:3H-retinol was less than that of albumin:14C-retinol when measured concurrently in three experiments (clearances 0.11 versus 0.75 mL/min, 0.21 versus 1.7 mL/min, and 0.29 versus 0.48 mL/min, respectively). Transfer of the radioactive retinol was more rapid than 125I-RBP or albumin, indicating that retinol was transferred independently of the proteins. The transfer index of retinol (clearance retinol:clearance L-glucose) was 0.73 +/- 0.085 compared to 2.1 +/- 0.36 for thiamin and 3.4 +/- 0.95 for riboflavin, both water-soluble vitamins with active transport systems. The retinol transferred to the fetal perfusate is not bound to RBP, as demonstrated by gel filtration chromatography and chromatography on a transthyretin affinity column, despite the availability of RBP in the cord serum added to the perfusate. The endogenous retinol in the cord serum is bound to RBP.(ABSTRACT TRUNCATED AT 250 WORDS)
J Dancis, and
M Levitz, and
J Katz, and
D Wilson, and
W S Blaner, and
R Piantedosi, and
D S Goodman
January 1993,
Journal of acquired immune deficiency syndromes,
J Dancis, and
M Levitz, and
J Katz, and
D Wilson, and
W S Blaner, and
R Piantedosi, and
D S Goodman
February 2018,
The Journal of clinical endocrinology and metabolism,
J Dancis, and
M Levitz, and
J Katz, and
D Wilson, and
W S Blaner, and
R Piantedosi, and
D S Goodman
October 2019,
Environmental health perspectives,
J Dancis, and
M Levitz, and
J Katz, and
D Wilson, and
W S Blaner, and
R Piantedosi, and
D S Goodman
January 2000,
Placenta,
J Dancis, and
M Levitz, and
J Katz, and
D Wilson, and
W S Blaner, and
R Piantedosi, and
D S Goodman
October 1996,
The Journal of clinical endocrinology and metabolism,
J Dancis, and
M Levitz, and
J Katz, and
D Wilson, and
W S Blaner, and
R Piantedosi, and
D S Goodman
January 1986,
Placenta,
J Dancis, and
M Levitz, and
J Katz, and
D Wilson, and
W S Blaner, and
R Piantedosi, and
D S Goodman
January 2004,
Clinical pharmacokinetics,
J Dancis, and
M Levitz, and
J Katz, and
D Wilson, and
W S Blaner, and
R Piantedosi, and
D S Goodman
January 1971,
Canadian journal of biochemistry,
J Dancis, and
M Levitz, and
J Katz, and
D Wilson, and
W S Blaner, and
R Piantedosi, and
D S Goodman
February 2000,
Journal of clinical anesthesia,
J Dancis, and
M Levitz, and
J Katz, and
D Wilson, and
W S Blaner, and
R Piantedosi, and
D S Goodman
January 1990,
Developmental pharmacology and therapeutics,
