A NEW ASSAY FOR THYROTROPIC HORMONE BASED UPON THYROIDAL PHOSPHOLIPID TURNOVER IN VITRO1

Abstract

THE assay of protein hormones still presents many problems. Most biological assay procedures are slow and inaccurate and require large numbers of animals. In vitro tests using tissues obtainable from the slaughterhouse therefore offer considerable advantages, especially to laboratories where the need for hormones assays arises only occasionally. To date, only a siugle in vitro assay for thyrotropin has been proposed (1) and the specificity and precision of this method have not been explored. We therefore considered it of interest to investigate further an in vitro effect of thyrotropin which was first described from this laboratory (2). This publication presents our findings regarding the sensitivity, specificity and limitations of the stimulation of radiophosphorus incorporation into the phospholipids of surviving thyroid slices by pituitary thyrotropic hormone.