Inhibition of placental amino acid uptake in rats following acute and chronic ethanol exposure.
The effects of acute and chronic maternal ethanol consumption on in vitro placental uptake of alpha-aminoisobutyric acid (AIB), cycloleucine, L-alanine (Ala), L-leucine (Leu), and L-lysine (Lys) were determined. Ethanol (4 g/kg. po) administered 2 hr prior to sacrifice, reduced (p less than 0.05) placental villous net uptake of cycloleucine and Ala by 29%. Prior chronic ethanol consumption depressed (p less than 0.05) placental uptake of AIB (38%), cycloleucine (45%), Ala (35%), Leu (25%), and Lys (34%). In vitro exposure of previously untreated villous fragments for 2 hr to 2 mg/ml of ethanol reduced (p less than 0.05) the net uptake of AIB and cycloleucine by 24% and 31%, respectively, whereas the minimum concentration of acetaldehyde required to cause a significant inhibition was 310 microM for AIB and 465 microM for cycloleucine. Ethanol (3 mg/ml) had no effect on AIB or cycloleucine net uptake if sodium was omitted from the incubation media. The efflux of AIB (10(-6)M) and cycloleucine (10(-6)M) from villous tissue was unaffected (p less than 0.05) by either ethanol (3 mg/ml) or acetaldehyde (600 microM) and obeyed first order kinetics. It was concluded that acute, and especially chronic, maternal ethanol consumption can depress the placental uptake of a variety of amino acids in the rat and, in the acute setting, the effect was on a sodium-dependent system involved in amino acid influx into placental cells.
D000079:Acetaldehyde / Q000494:pharmacology; D000409:Alanine / Q000378:metabolism; D000437:Alcoholism / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism*; D000621:Aminoisobutyric Acids / Q000378:metabolism; D000818:Animals; D001622:Betaine / Q000378:metabolism; D003515:Cycloleucine / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007930:Leucine / Q000378:metabolism; D008431:Maternal-Fetal Exchange / Q000187:drug effects; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D000596:Amino Acids; D000621:Aminoisobutyric Acids; D003515:Cycloleucine; D000431:Ethanol; D001622:Betaine; D007930:Leucine; D000079:Acetaldehyde; D000409:Alanine