性差よりみた甲状腺機能の本態に関する実験的研究
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概要
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It has been clincically known that thyroid diseases are seen more frequently in the female than in the male. However, the sexual differences are not as yet fully explained. For this purpose, effects of castration on the thyroid function and effects of gonadal steroid hormones on the thyroid function of the castrate mature rats of both sexes were investigated. For determination of the thyroid function, radioactive iodine I<SUP>131</SUP> was used and remarkable findings were obtained.<BR>The results are summarized as follows : <BR>1) Effects of castration on the thyroid function were manifested by hypofunction, usually, 14 days in the female and 42 days in the male, after castration, and greater changes were found in females than in males, and the effects were persisted even 2 months after the castration. It may be concluded that those greater changes in females without distinction to post-operative period had apparently indicated the fact that there are substantial differences of the thyroid function between male and females.<BR>2) It is the matter of course that sexual differences should be looked for in the gonads. But, for the explanation of this mechanism, 3 kinds of steroid hormones ; estradiol benzoate, progesterone, and testosterone propionate were administered to the castrated mature rats and these effects on the thyroid function were examined. Marked differences have been found to exist between two sexes.<BR>(1) Estrogen has an accelerating effects on the thyroid uptake of I<SUP>131</SUP> for the female, and on the release of thyroid hormone in the blood of male rats. This diverse response against estrogen is considered to be attributable to the difference in the affinity of the thyroid to estrogen.<BR>(2) When progesterone is injected to the castrated female rats, no changes were found, and in the male, decreased thyroid uptake of I<SUP>131</SUP> was found 14 days, and no obvious changes occurred 2 months after castration.<BR>(3) Androgen has no constant effects on the thyroid of the castrated both sexes.<BR>(4) By the fact that estrogen has coherent effects on the thyroid while androgen causes no change, it can be assumed that the sexual differences are chiefly attributable to estrogen.<BR>(5) The results of steroid hormones injection indicated that in the female thyroid is closely related with the gonad, while the thyroid in the male is not under this control.<BR>(6) Estrogen has an accelerating effects on the female thyroid uptake of I<SUP>132</SUP> irrespective of post-operative periods, suggests the reason for the more frequent occurrence of thyroid diseases in the female.<BR>3) In order to explain the mechanism in which estrogen is the primary fractor on the sexual differences of the thyroid, estrogen was administered to the hypophysectomized female rats and its effect was investigated. Thyroid uptake of I<SUP>131</SUP> showed remarkable increase in comparison with the control groups. By this fact, it can be noted that the estrogen has a direct effects on the thyroid.
- 日本内分泌学会の論文