To investigate the relationship between female obesity and thyroid function, serum T3 and T4 in the females who lived in Shiramine-village, Ishikawa prefecture were measured. The results obtained were as follows. 1) Significant positive correlation between obesity index and the levels of serum T3 was observed in the normotensive subjects only under 39 years old. On the other hand, there was no significant correlation between obesity index and the levels of serum T4 in the normotensive subjects under 39 or over 40 years old. These results suggest that obesity is prevented in part by the increase of serum T3 in the normotensive females under 39 years old. 2) In the subjects whose obesity index was over +10%, the levels of serum T4 in the borderline hypertensive subjects were significantly lower than those in the normotensive subjects. Therefore, it could not be demonstrated that there was positive relationship between the increase in blood pressure induced by obesity and the increase in the levels of thyroid hormon.
