Inhibition by Normal Immunoglobulins of Thyrotrophin-Stimulated Production of Cyclic Amp in Slices of Normal Human Thyroid

Abstract

Slice preparations of normal human thyroid tissue have been used to investigate the effect of normal immunoglobulin G (IgG) on thyrotrophin (TSH)-induced accumulation of cyclic AMP. Incubation of slices in the presence of both TSH and normal IgG for 20 min reduced the stimulation of cyclic AMP accumulation elicited by TSH alone by approximately 30%. However, preincubation of slices with IgG for 100 min before addition of TSH virtually abolished the response to TSH. The latter effect of normal IgG was reversible, and removal of IgG before exposure to TSH allowed an unimpaired cyclic AMP response to TSH. The implications of these observations with respect to the application of this system to the functional bio-detection of thyroid-stimulating antibodies in IgG fractions from thyrotoxic sera are discussed.

Measurement of low concentrations of bovine thyrotrophin by iodide uptake and organification in porcine thyrocytes

“…Although the reasons for this inhibition are unclear such effects have been described by others (Fayet & Hovsépian, 1979;Dickson et al 1981; Ambesi-Impiombato et al 1982) even after specific purification of thyroid-stimulating immunoglobulins (Bidey, Marshall & Ekins, 1980;Kjaerulff et al 1984). Furthermore, these effects have been seen with assays utilizing both receptor-binding effects and stimulation of cyclic AMP (Kjaerulff eí al.…”

Isolation of thyroid stimulating immunoglobulins by affinity chromatography using protein A sepharose

“…However, following this procedure crude-IgG from normal controls still inhibits the binding of [I25I]TSH and also the stimulation of cAMP accu¬ mulation in thyroid slices in a dose-dependent way (Sato et al 1977;Fenzi et al 1979;Bidey et al 1980;Bliddal 1981). However, following this procedure crude-IgG from normal controls still inhibits the binding of [I25I]TSH and also the stimulation of cAMP accu¬ mulation in thyroid slices in a dose-dependent way (Sato et al 1977;Fenzi et al 1979;Bidey et al 1980;Bliddal 1981).…”