Placental alcohol metabolism in chronic alcohol abuse

The activities of aldehyde dehydrogenase (ALDH; EC 1.2.1.3) and alcohol dehydrogenase (ADH; EC 1.1.1.1) were measured in term placentas of 13 alcoholic women and 16 matched controls. With acetaldehyde 8 mmol/l as substrate, the ALDH activity was 29.1 +/- 12.2 and 34.4 +/- 15.3 mU/g of wet weight (mean +/- SD; p greater than 0.4) for alcoholics and controls, respectively. With 50 mumol of acetaldehyde, ALDH activity was undetectable in both groups. No ADH activity could be detected in the placentas. The weights of placentas and newborns were significantly lower in the alcoholic group (placentas: 526 +/- 116 vs. 653 +/- 77 g, p less than 0.005; newborns 2,878 +/- 417 vs. 3,595 +/- 346 g, p less than 0.001). The results suggest that in chronic alcohol abuse, the placenta plays a negligible role in the metabolism of ethanol and acetaldehyde.