Action of partially purified ACTH-potentiating substance from rat serum on isolated rat adrenal cells.
スポンサーリンク
概要
- 論文の詳細を見る
A serum extract possessing ACTH-potentiating activity was partially purified by Sephadex G-100 gel filtration. Fractions from 9, 000 to 40, 000 in molecular weight (APS-Fr) potentiated the corticosterone production induced by synthetic adrenocorticotropic hormone (ACTH<SUB>1-24</SUB>). Approximately 5μg (as protein) of APS-Fr in 0.5 ml medium showed the maximum activity to potentiate the response of isolated rat adrenal cells to ACTH<SUB>1-24</SUB> Puromycin, cycloheximide and actinomycin D did not abolish the potentiation by APS-Fr of ACTH<SUB>1-24</SUB>-induced steroidogenesis. The log-dose response curve for ACTH<SUB>1-24</SUB> was shifted toward the side representing lower doses of ACTH<SUB>1-24</SUB> by APS-Fr, but the maximum response was not changed. In a typical experiment, the median effective dose (ED50) for ACTH<SUB>1-24</SUB> was decreased from 5.2×10<SUP>-11</SUP> M to 3.0×10<SUP>-12</SUP> M. ACTH<SUB>1-24</SUB>-induced production of cyclic AMP was also increased by APS-Fr. Time courses of both corticosterone and cyclic AMP production induced by ACTH<SUB>1-24</SUB> did not differ qualitatively in either the presence or absence of APS-Fr, although they showed a marked difference quantitatively. When dibutyryl cyclic AMP was used in place of ACTH<SUB>1-24</SUB>, APS-Fr did not potentiate steroidogenesis. These results suggest that APS-Fr acts at a step between the binding of ACTH to its receptor and the formation of cyclic AMP. ACTH<SUB>1-24</SUB>-induced steroidogenesis which was increased by increasing concentration of calcium in the medium, was further increased by addition of APS-Fr. The calcium requirement for the same degree of response was decreased by addition of APS-Fr, in a similar way to when a higher concentration of ACTH<SUB>1-24</SUB> was used.
- 公益社団法人 日本薬理学会の論文
著者
関連論文
- ACTH Bioassay Using Isolated Adrenal Cells and Its Application to Determination of Serum and Pituitary ACTH Levels in Morphine-Injected Rats
- HISTAMINE-INDUCED ACTH SECRETION AND INHIBITORY EFFECT OF ANTIHISTAMINIC DRUGS
- Action of partially purified ACTH-potentiating substance from rat serum on isolated rat adrenal cells.