Corticosterone Secretion in Dexamethasone Blocked Rats

Corticotropin activity can be measured by the increase of corticosterone in venous blood of hypophysec-tomized or dexamethasone-blocked rats, as a singledose test when receptor affinity for ACTH receptor is found with a test compound. The test can be used to measure time-response curves of corticotropin preparations, and compounds with a adrenal stimulating activity (Vogel 1969a,b). The use of hypophysec-tomized rats for evaluation of the pituitary response 

In the context of repeated dose studies for endocrine safety evaluation, a modification of this test is built into the procedure, as described above (A4-1). 

Using 3 doses of test compound and standard, activity ratios with confidence limits can be determined after each time interval with the 3 + 3 point assay giving evidence for the duration of action (Vogel 1969a,b). 

In contemporary methods, the assay of corticosterone is performed by immunoassay in unextracted serum samples or in serum and tissue extracts by HPLC. In the classical methods, fluorometry was applied. Pekkarinen (1965) used fluorometric corticosteroid 

Schuler W, Schaer B, Desaulles P (1963) Zur Pharmakolo-gie eines ACTH-wirksamen, vollsynthetischen Polypep-tids, des b 1-24-Corticotropins, Ciba 30920-Ba, Synac-then. Schweiz Med Wschr 93 1027-1030 Seeman TE, Robbins RJ (1994) Aging and hypothalamic-pituitary-adrenal response to challenge in humans. Endocr Rev 15 233-60 

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