Alcohol preference and hepatic alcohol dehydrogenase activity in adult Long-Evans rats is affected by intrauterine sibling contiguity.

Alcohol preference and hepatic alcohol dehydrogenase activity in adult rats are known to be sexually dimorphic. Intrauterine sibling contiguity (the intrauterine position of a fetus relative to adjacent siblings of the same or opposite sex) alters selected reproductive, behavioral and enzymatic sexual dimorphisms via intersibling sex hormone transfer. We postulated that sibling contiguity would affect alcohol preference and hepatic alcohol metabolism in adult rats. The results of our study demonstrate that adult mMm male Long-Evans rats (genetic male rat developing in utero between two male siblings) had significantly lower ethanol preference, attained higher blood alcohol levels after standard ethanol "challenge" doses and had significantly lower hepatic alcohol dehydrogenase activity than either male siblings developing in utero between two females (fMf) or genetic females developing between two males or between two females (mFm or fFf). Hepatic cytosolic aldehyde dehydrogenase activity was higher in adult female than male rats regardless of nearest neighbor siblings. It is suggested that the differences in ethanol preference and hepatic alcohol dehydrogenase activity between the adult mMm and fMf male rats is due to differences in prenatal hormonal environment which can modulate sexual dimorphisms in alcohol intake and metabolism in the adult.