Endocrine Abstracts

Studies in mice and rats suggest that legions of hippocampus interfere with memory for space and context and can have a significant effect on memory storage. The goal of the present study was to investigate the effect of maternal hypothyroidism, and thyroxin therapy on the neuronal density of the subiculum.

Twenty five adult female Wistar rats were divided into experimental groups (Exp) 1 and 2 and control. The Exp groups made hypothyroid (500 mg/l PTU in drinking water). The Exp 2 received levothyroxin as well (1 mg/l in drinking water). The treatment regimes were the same throughout the experimental period. Two 20 days old offspring were randomly selected from each litter, deeply anesthetized (0.2 ml of 2% xylazine), perfused by 10% formaldehyde, their brains processed for histological preparation and the parasagittal sections (9 μm) stained in tuloidin blue. By using the dissector method, the numerical density (Nv) of subicular region of the left hemisphere were estimated and statistically analyzed by JMP software in all groups.

The results show significant differences in subicular Nv in Exp 1 when compared with control and/or Exp 2 (P<0.0001). It seems that thyroxin therapy may improve the effects of hypothyroidism on the neuronal growth and extension of dendritic arborization of subicular neurons.