A RE-EXAMINATION OF THE TADPOLE IN METAMORPHIC STASIS AS A RECIPIENT IN A BIOASSAY FOR THYROID-STIMULATING HORMONE

Abstract

SUMMARY The tadpole, in metamorphic stasis, has been used as a bioassay recipient for thyroid-stimulating hormone (TSH). The validity of its use for this purpose, however, has not been tested critically, particularly with respect to the effect of other hormones, most notably, growth hormone (GH) and luteinizing hormone (LH). Growth hormone has been shown to influence thyroid function and LH is a common contaminant of pituitary TSH preparations. Tadpoles of Rana pipiens, arrested at a particular metamorphic stage, received various concentrations of LH alone, a combination of doses of GH and TSH, or GH and rat anterior pituitary extract. Growth hormone was ineffective in re-inducing metamorphosis in 78% of cases, whereas LH stimulated metamorphosis in the tadpoles.