title: The measurement of hypothalamic releasing hormone content and activity in the unanaesthetized rat by means of carotid artery cannulation.
abstract: To gain insights into quantitative changes in hypothalamic substances which affect the function of the anterior hypophyseal lobe, we developed a technique for carotid cannulation allowing sequential measurements of plasma levels of an affected hormone after injection of such a factor. The principle involves the use of a previously cannulated rat in an unanaesthetized unstressed condition. The hypothalamic extract or LH-RH injected into the cannulas of such animals leads to rapid peaks of LH in peripheral blood removed from the same cannulas within 6 to 8 min, followed by a slow decrease. At least 50% of the peak value is usually found within 3 min. The technique yields quantitatively reproducible results, and appears suitable for measuring relative potencies of test extracts against pure standards and, within as yet undetermined limits, for kinetic studies.
mesh_terms: D000818:Animals; D002339:Carotid Arteries; D002369:Castration; D002404:Catheterization; D004305:Dose-Response Relationship, Drug; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology*; D007269:Injections, Intra-Arterial; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D008473:Median Eminence / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D013268:Stimulation, Chemical
chemical_list: D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone