Bioassay of thyrotropin.

Abstract

MOST of the procedures for the biosassy of thyrotropin involve subcutaneous or intraperitoneal administration of a series of test doses of the hormone over a period of 3 to 5 days (cf., Albert, 1949; Turner, 1950). Ghosh et al. (1951) developed an assay based on the uptake of I131 by the thyroid of the hypophysectomized rat following a series of 5 subcutaneous injections of thyrotropin. Subsequently, Overbeek et al. (1953) substituted rats prefed with iodocasein for hypophysectomized animals, and administered thyrotropin in 2 intraperitoneal doses. A ten-fold increase in sensitivity was achieved over the method of Ghosh et al. (1951). Recently, Kriss and Greenspan (1954) described a bioassay based on the enhanced uptake of P32 by the chick thyroid following a single intracardiac injection of thyrotropin. The sensitivity of this method was about 10 times that observed after a single intraperitoneal injection of thyrotropin (Crooke and Matthews, 1953).