A NEW BIOASSAY TECHNIQUE FOR THE MEASUREMENT IN VITRO OF THYROTROPHIC HORMONE IN SERUM AND IN PITUITARY EXTRACTS

Abstract

SUMMARY: A new technique by which thyrotrophic hormone (TSH) can be rapidly measured in vitro in the serum of euthyroid subjects and in human pituitary extracts is presented. In euthyroid male subjects levels of TSH in serum ranged from 0 to 30·1 i.u. × 10⁻³/100ml., the mean value being 10·8. In normal menstruating women the mean value was 4·8 and the range 0 to 21·5 i.u. × 10⁻³/100 ml. In human pituitary extracts, TSH could be detected in all fractions tested, but the amount of activity present was greatest in the gonadotrophin fraction. When the latter was separated into the FSH and LH components the TSH activity was found to be mainly associated with the LH fraction. The specificity of the method has been examined by incubating thyroid tissue with other hormones of pituitary origin and measuring their effect on the response to TSH. It is concluded that any interference with the assay method produced by FSH and LH is due to their contamination with TSH.