Endocrine Abstracts

Deficient production of thyroid hormones in maternal organism may have a drastic impact on brain development of the offsprings. Among the people originated from the regions with essential deficiency of iodine in foodstuff there is a high chance for prevalence of mental retardation and neurological cretinism with all possible complications.

The present study analyses changes in emotional state (open field testing), learning ability and memory processes (maze testing) of the progeny of dams suffered from iodine deficiency of different severity during 3 monts before mating. Control group of rats received standard diet.

The diet with very low iodine content resulted in a low level of thyroxin in maternal serum and development of neurological deficiency in progeny. The offsprings manifested decreased motor activity and that was clearly demonstrated in open field testing as well as during maze testing. Besides, decreased learning ability was revealed in experiments with maze. More pronounced changes in both mentioned experimental conditions were observed in the progeny of dams with more restricted iodine diet (addition of KClO₄ to the basic diet) – they show significant decrease in the number of crossed squares, in the number of entering into the central squares and vertical standings as well as increased frequency of grooming. In this group of animal’s learning disability during maze testing was revealed clearly.

Addition of the iodine to the diet prevents development of all mentioned changes in animal’s behavior in open field and the maze.

The data obtained lead to the conclusion that offsprings of the dams suffered from iodine deficiency of different severity produced decrease motor activity and learning disability. The intensity of these abnormalities depends on the extent of iodine deficiency.