Abstract
Various experimental studies on thyroid function of newborn rats have shown, that oral application of iodine to pregnant and newborn rats may be followed by neonatal hypothyroidism,whereas cutaneous application of PVP-iodine is followed by hyperthyroidism.To elucidate the different results,PVP-iodine was applicated cutaneously to pregnant and newborn rats.Its effect on thyroid function and brain development was studied between the 1st and 26th day of life. RESULTS: T3,T4 and TSH concentrations remained within the limits of the control group on day 1,5,10 and 18 of life.On day 26 T4-values were significantly higher in the "iodine"-group than in controls(3.9±0.4 resp.2.9 ± 0.2 μg/dl;p<0.05) but remained still within the euthyroid range. T3 and TSH-values were not different between both groups.Weight gain of body and brain was similar in both groups. Histological studies of the cerebellum gave no differences. CONCLUSION: Iodine overload during gestation and newborn period does not disturb thyroid function in the newborn rat if iodine is offered on a constant high level starting with pregnancy. With regard to earlier findings it may be concluded that the iodine-dependent autoregulation of thyroid function is affected more by the set-point of iodine excess than by the amount of iodine supply.
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Lehming, R., Klett, M., Döhler, KD. et al. IODINE EXCESS AND THYROID FUNCTION IN THE NEWBORN RAT. Pediatr Res 18, 1222 (1984). https://doi.org/10.1203/00006450-198411000-00130
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DOI: https://doi.org/10.1203/00006450-198411000-00130