ACTH Bioassay Using Isolated Adrenal Cells and Its Application to Determination of Serum and Pituitary ACTH Levels in Morphine-Injected Rats

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概要

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• A bioassay method for the determination of ACTH in rat the serum was established. For the separation of ACTH from the serum, ACTH was adsorbed to Quso G 32 and then eluted with 40% acetone-1% acetic acid solution, and the eluate was evaporated at 45°C. The dried sample was incubated with isolated rat adrenal cell suspension and produced corticosterone was determined. The amount of ACTH was estimated from the standard dose-response curve. The minimum detectable amount of ACTH<SUB>1-24</SUB> added in the ACTH-free serum was 5 pg. Recovery and reproducibility of the assay were satisfactory for practical use.<BR>The bioassay was applied to the determination of the ACTH level in the rat serum after morphine administration. After a 20mg/kg of morphine hydrochloride ip, ACTH concentration in the serum increased rapidly and its maximum level was observed 5min after the injection. The ACTH then decreased gradually, but it was still at a high level 60min after the injection. With an sc injection of the same amount of morphine, ACTH in the serum increased gradually and the maximum concentration was seen 60min after the injection. Despite the difference of time courses of ACTH concentration in the serum with different routes of morphine administration, the time courses and the maximum levels of corticosterone concentration were similar. An ACTH level in the pituitary was maintained at a pre-injection level even 60min after a 20mg/kg of morphine ip. In the experiment of morphinization, increasing doses of morphine were injected sc twice daily for 10 days. The ACTH concentration in the serum of morphinized rats did not increase with a test dose of 20mg/kg of morphine ip, but increased markedly with a 5 mg/kg of nalorphine hydrochloride ip. The ACTH level in the pituitary increased by about 40% in the morphinization.

• 社団法人 日本内分泌学会の論文

著者

• MORITA YOSHIKO

  Division of Bio-Function Research, Biomedical Research Laboratories, Jikei University School of Medicine

• KOYAMA KUNIKO

  Division of Bio-Function Research, Biomedical Research Laboratories, Jikei University School of Medicine

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.

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