山梨医科大学雑誌　第2巻4号　145-151(1987)

ACTH Bioassay and Plasma Bioactive ACTH
Concentrations in Children

Kenji OHYAMA, Makoto SHIMIZU and Kiyohiko KATO

Abstract: Using a sensitive bioasay method with isolated rat adrenal cells, plasma bioactive (b-) ACTH concentrations were measured in cord blood, and in infants and children. The extraction rate of plasma b-ACTH measured using silicic acid ranged from 70-75%. In the dose response curve for corticosteroid production by isolated adrenal cells, 1O pg of ACTH(1-39) could be detected as being significantly different from the blank values. The intra-assay coefficient of variance was found to be 7.2%, and that of inter-assay variance was 13.4%. Plasma b-ACTH concentrations were noticeably higher in cord blood than in maternal blood (cord: 162.2±39.4 pg/ml; mother: 32.4±10.0, mean±SD, P<0.001). This fact suggests that b-ACTH is secreted by the fetal pituitary at birth. In each of the samples obtained at 8:00 a.m. and 8:00 p.m., the plasma b-ACTH levels were significantly higher in infants than in children (P<0.01). Furthermore, in infants and children, the plasma b-ACTH levels obtained at 8:00 a.m. were substantially higher than at 8:00 p.m. (P<0.01). In response to insulin-induced hypoglycemia, peak values (165.7±39.0) were obtained 3O min after insulin injection in those with constitutional short stature, with the patterns of b-ACTH secretion being similar in each subject. These results suggest that b-ACTH shows a circadian rhythmicity not only in children but also in infants, and that the hypoglycemic stimulus rapidly induces a release of b-ACTH with slight individual variation. Accordingly, we feel that ACTH bioassay is particularly promising for the elucidation of various pathological states in pituitary-adrenal disorders.

Key words: Adrenocorticotropin, Bioassay, isolated adrenal cell



ACTH bioassay法および小児期の血漿bioactive ACTH濃度

大山建司，清水　節，加藤精彦

　Sayersの方法に準じ，ラット副腎遊離細胞をもちいた高感度ACTH-bioassay系を確立した。血柴ACTHはsillicic acidにて抽出し，抽出率は70-75%であった。Bioassay系の最低感度は10pg，測定内，測定間誤差は各々7.2%，13.4%であった。対象は，分娩時臍帯血および母体血，乳幼児学童，インスリン負荷試験を行った体質性低身長児である。臍帯血 b-ACTH濃度は母体血に比し有意に高値であった(膿帯血162.2±39.4pg/ml，母体血32.4±10.0，mean±SD，P<0.001)。乳児期の b-ACTH濃度は幼児学童期に比し有意中(P<0.001)の高値を示し，又いずれの年齢においても午前8:00時 b-ACTH濃度は午後8:00時に比し有意(P<0.01)に高値であった。インスリン負荷に対しては，全例30分に頂値(165.7±39.0)を示す分泌増加を認め60分で前値に復し，個体差は少なかった。以上の結果より，出生時胎児下垂体より b-ACTHが分泌されていること，乳児期からACTH分泌に日内変動がみとめられること，低血糖刺激に対し b-ACTHは鋭敏に反応し反応パターンに個体差が少ないことが明らかとなった。今後ACTH-bioassayは下垂体-副腎皮質系機能障害の検査として有用性が高いと考えられる。

キーワード：副腎皮質刺激ホルモン，バイオアッセイ，副腎遊離細胞



本文は、編集委員会の意向によりインターネットには公開しておりません。図書館等でご覧ください。

Texts are not availavle on Internet.



目次・Contentsに戻る