This study aimed to investigate whether exogenous thyroxine(T₄) treatment to alcohol-fed dams would ameliorate the detrimental effects of alcohol on the postnatal development of neuropeptide- Y(NPY)-containing neurons of the cerebral cortex and hippocampus of the offspring.

Time-pregnant rats were divided into three groups. An alcohol-fed group A received 35 calories of liquid alcohol diet daily from gestation day 6; control group B was fed a liquid diet in which dextrin replaced alcohol isocalorically; and alcohol+T₄ group C received 35 calories of liquid alcohol diet and exogenous thyroxine subcutaneously. The features of the growth and maturation of rat brain tissue were observed at 0, 7, 14, 21 and 28 postnatal days via immunohistochemistry.

Group C showed prominent NPY immunoreactivity in the cerebral cortex compared to group A and B at P7. In group C, NPY-containing neurons were widely distributed in the all layers of cerebral cortex after P14. Also, numerical decreases of NPY-containing neuron were not found according to increasing age in group C. A decrease of NPY-containing neurons, however, was clearly observed in group A compared to group C at P28. In the hippocampus, similar patterns appeared in groups B and C after P7. Especially, in groups B and C, NPY-containing fibers formed plexus in the cerebral cortex and hippocampus at P14.

These results suggest that the increase of NPY synthesis caused by maternal administration of exogenous thyroxine may convalesce fetal alcohol effects, one of the effects of the dysthyroid state following maternal alcohol abuse.