A Comparison of Various Indicators of Murine Thyroid Stimulation by LATS

To obtain an in vitro method of LATS assay which is equally sensitive to a McKenzie bioassay, we compared the quality of cAMP generation-stimulation, thyroidal adenyl cyclase stimulation, and the stimulation of T3-release from mouse thyroid slices. Among those indicators of thyroid stimulation, stimulation by IgG of the release of T3 from incubated thyroid slices is the most sensitive, reproducible and reliable indicator, reflecting faithfully the results of a McKenzie bioassay. Stimulation of cAMP generation in slice manifested less sensitivity, but reasonable reproducibility. However, adenyl cyclase stimulation by IgG of patients with Graves' disease was erratic in two successive experiments, probably due to a non-specific effect of IgG. When adenyl cyclase stimulation was adopted as a sole indicator of thyroid stimulation, the results must be interpreted cautiously.