Light microscopic immunocytochemical demonstration of thryoid-stimulating hormone (TSH) receptors on normal rat thyroid cells

We present a method for immunohistochemical demonstration of surface-associated thyroid-stimulating hormone (TSH) receptors on direct imprints of rat thyroid follicular cells at the light microscopic level, by use of dinitrophenyl (DNP)-labeled bovine TSH as the primary probe in a DNA-hapten sandwich staining (DHSS) procedure. The light microscopically invisible diaminobenzidine (DAB) product of the enzyme reaction was amplified with a DAB enhancement technique (silver amplification), which yielded a reliable and distinct light microscopically visible cell surface staining. The consistently negative control results after inhibition with TSH receptor-specific reagents provide evidence in support of immunohistochemical localization of surface membrane-associated TSH receptors.