Factors other than ACTH for manifestation of circadian rhythm in blood corticosterone levels in the rat.

DOI JASI Web Site Web Site PubMed 1 Citations

Bibliographic Information

Other Title
  • ラット副腎皮質ホルモンの日周リズム成立に対する ACTH 以外の因子について
  • ラット副腎皮質ホルモンの日周リズム成立に対するACTH以外の因子について〔英文〕
  • ラット フクジン ヒシツ ホルモン ノ ニッシュウ リズム セイリツ ニ タイ

Search this article

Description

In order to examine further the existence of factors contributing to the circadian adrenocortical rhythm, blood corticosterone response to ACTH was determined in the morning and in the evening, using rats pretreated with dexamethasone and Nembutal. By the treatment with dexamethasone at 1300 h for 2 days, plasma ACTH was decreased to nondetectable levels, and the daily variations of blood corticosterone levels were abolished. Adrenal corticosterone content was also minimized. In these rats, following a single injection of 2 or 20 mIU ACTH, a significant increase of blood corticosterone level was observed and this response was greater in the evening than in the morning. An addition of the serum obtained from the rat in the evening and freed both ACTH and corticdsterone augmented the responsiveness of cultured adrenal cells to ACTH. This ACTH potentiating effect was not detectable in the serum obtained in the morning. In intact rats, the evening levels of plasma ACTH showed a large individual variation. And the ACTH mean level was higher in the evening than in the morning. The following conclusion was drawn; 1) adrenocortical response to ACTH is augmented by humoral factors other than ACTH. 2) however, peak of circadian adrenocortical rhythm may be brought about mainly by pulsatile secretion of ACTH in the evening.

Journal

Citations (1)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top