下垂体後葉ホルモンのTSH分泌並びに甲状腺機能に及ぼす影響に関する臨床的並びに実験的研究
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It is a known fact that the posterior pituitary hormones, as the chemical mediator of hypothalamic activity play an important role, in the secretory function of anterior pituitary.<BR>This concept has been built up on the indirect experimental facts : That the release of GTH, TSH and ACTH respectively were elucidated from the increased activity of target endocrine glands, i.e. gonads, thyroid and adrenal cortex following the injection of pituitary posterior hormone.<BR>Direct measurement of the anterior pituitary hormone in the blood will certainly clarify the situation.<BR>In the previous reports from our clinic, Tsuji and Ogura reported on the technique of direct measurement of plasma TSH-level, using thyroid slices and Warburg technique. With method it is now possible to study the hourly response of plasma TSH-level with only 0.5 cc plasma.<BR>The author has tried to study the effect of pituitary posterior hormones, such as pitressin and Oxytocin, on the release of TSH from the anterior pituitary lobe following this method.<BR>As the indicator of the anterior pituitary activity in humans and dogs, plasma TSH level was determined by Tsuji-Ogura's bio-assay method.<BR>Furthermore, in the experiments with rats, Vasopressin effect via TSH upon thyroid was determined by the increase of the following thyroid items : weight of thyroid, uptake of I<SUP>131</SUP>, PBI<SUP>131</SUP> convertion ratio, T/S I<SUP>131</SUP> ratio, thyroid index corresponding experiments were carried out with oxytocin for the purpose of comparison. The result are summarized as follows : <BR>(1) Vasopressin, subcutaneously injected, gives rise to the acceleration of the pituitary thyroid activity in man, dog and rat.<BR>This action of vasopressin in observed as<BR>1) Elevation of plasma TSH level directly following the injection of vasopressin and<BR>2) acceleration of thyroid activity. Oxytocin produces the same kind of enhancement of pituitary thyroid activity but in a for milder form (Fig. 1, 4, 6, 7, 8, 12).<BR>(2) Vasopressin injection in subjects with various endocrine diseases, produces abnormal plasma TSH response as compared with the results of vasopressin test in normal subjects. Those cases with abnormally low anterior pituitary activity or pituitary destruction failed to respond upon vasopressin with increase of plasma TSH-level. Thus a fairly distinct functional test of anterior pituitary lobe could be developed with direct measurement of plasma TSH-level.<BR>(3) Resection of the pituitary in rats abolishes the thyroid response upon vosopressin injection. Stalk section combined with celophanisation of the resected stalk brings about the lowering of plasma TSH. Vasopressin injection in the dogs with stalk section, produces a fairly distinct increase of plasma TSH-level.<BR>These facts point out the plausible effect of.vasopressin upon pituitary-thyroid system, but this effect is brought about humorally and always first via anterior pituitary lobe.<BR>(4) Medicaments such as reserpine, chlorpromazine and phenobarbital, which are believed to act upon hypothalamus, were given to the animals and the vasopressin effect upon plasma TSH-level was examined.<BR>Only phenobarbital was able to suppress the increase of plasma TSH-level which normally follows the injection of vasopressin. The other two drugs showed no effect upon plasma-TSH response upon vasopressin.
- 日本内分泌学会の論文