Effect of the age of pregnant females on brain development in the offspring.

We examined offspring of 9-10 and 3.5-4 month-old female rats. Female offspring (14, 21, 28, 35, and 40 days) of old rats had higher body weight than offspring of young animals. No intergroup differences were revealed in the body weight of male offspring. At the age of 40 days the offspring of old females differed from the offspring of young rats by higher absolute weight of the brain (females), lower size of ganglionic neurons in the parietal lobe (males and females), and lower blood testosterone concentration (males). Thirty-day-old offspring of old rats exhibited higher locomotor activity and lower degree of anxiety compared to the offspring of young animals.