The purpose of this study was to determine the contents of iodine and selenium in the thyroid, pituitary, adrenal glands and ovaries of female rats under the influence of propylthiouracil (PTU) and the effects of a single dose of potassium iodide (KI) administered two days after the administration of PTU. For the analyses, electron probe microanalysis (EPMA), wavelengthdispersive spectrometry (WDs) and point analysis were used in this study. Ninety-six hours after the first PTU administration the thyroid gland iodine level decreased three-fold in iodide positive points (I-PPs) and the percentage of positive points (%I-PPs) fell by one half. Administration of a single dose of potassium iodide slightly increased the iodine level in I-PPs and restored %I-PPs to the control level. After PTU administration the selenium positive points (Se-PPs) in the thyroid gland decreased by one half, but KI did not help to level these changes. In ovaries, pituitary and adrenal glands PTU administration did not significantly alter the average levels of iodine and selenium, but the Se-PPs and % I-PPs varied over a wide range. Administration of KI restored the levels of iodine and selenium in the pituitary and adrenal glands, but worsened the changes of iodine in ovaries.