Thyrotropin receptors in adipose tissue, retro-orbital tissue and lymphocytes

Thyrotropin (TSH) receptors on retro-orbital muscle and fat have been implicated in the pathogenesis of Graves' exophthalmos and it has been suggested that TSH has a direct effect on human fat metabolism. We have therefore investigated the interaction of biologically active 125I-labelled TSH with membranes prepared from human adipose, retro-orbital and thyroid tissue. Since lymphocytes contain receptors for several polypeptide hormones, TSH binding to lymphocyte membranes was also studied. We were unable to demonstrate TSH receptors in adult human adipose tissue, retro-orbital muscle and fat, or peripheral blood lymphocytes. In contrast, adult and neonatal guinea pig adipose tissue membranes showed similar TSH binding characteristics to guinea pig thyroid membranes.