EFFECTS OF THYROIDECTOMY AND TRIIODOTHYRONINE (T3) ON THE SYNTHESIS AND RELEASE OF GROWTH HORMONE (GH) AND PROLACTIN
1971 年 21 巻 5 号 p. 551-562
詳細
1971 年 21 巻 5 号 p. 551-562
The rates of synthesis and release of growth hormone (GH), prolactin, and whole protein of the rat anterior pituitary were determined using an in vitro method.
1. Thyroidectomy caused a marked decrease in both synthesis and release of GH. Decreased synthesis was restored by a single injection of T3 (20μg/100g body weight) within 12hr. Decreased GH release was also increased gradually by T3 injection. The percentage release of GH was increased by thyroidectomy and the increase was depressed by T3 injection.
2. Prolactin synthesis was increased by thyroidectomy, and the increased synthesis was suppressed as early as 3 hr after T3 injection. Prolactin release was not affected by thyroidectomy. The percentage release decreased significantly after thyroidectomy.
3. Whole protein synthesis was increased by thyroidectomy and the increase was suppressed by T3 injection. The whole protein release and the percentage release were not influenced by thyroidectomy and decreased significantly within 3 hr after T3 injection.
4. Added in vitro, T3 had no effect on synthesis of whole pituitary protein, but whole protein release was clearly suppressed at concentrations as low as 10-7m.
These results indicated that thyroid hormone stimulated GH synthetic processes and depressed GH release processes. Prolactin synthetic processes were depressed by thyroid hormone. The mechanisms of the thyroid hormone action and the physiological significance of the facts observed are discussed.
