Time-related thyroid stimulation by thyrotropin and thyroid-stimulating antibodies, as measured by the cytochemical section bioassay.
The time course of response of thyroid sections in the cytochemical bioassay to either TSH or thyroid-stimulating antibodies is bell shaped. The maximal staining for lysosomal naphthylamidase activity achieved was found to be the same regardless of the dose of stimulator applied; however, the rate at which the maximum was attained was dose dependent. Sections exposed to 10(-1) mU/liter TSH showed a maximal response at 120 sec, and those exposed to 10(-3) mU/liter TSH showed a maximal response at 210 sec. A similar dose-time effect was seen with immunoglobulin G from a thyrotoxic patient. Thus, by selecting a specific exposure time, a dose-response curve to the stimulator was obtained. A dose-response curve to a range of concentrations from 10(-4)-10(-1) mU/liter TSH was obtained by exposing sections to the hormone for 90 sec. TSH (10(-3) mU/liter) produced a response significantly different (P less than 0.0025) from the control. However, 10(-5) mU/liter TSH produced a response significantly different (P less than 0.0025) from the control after an exposure time of 180 sec, and the range of the dose-response curve at this exposure time was 10(-6)-10(-3) mU/liter TSH. Each point on these two dose-response curves was determined in quintuplicate, and precision profiles were constructed. The assay performed at 90 sec had a lower relative precision of 30% at a dose of 10(-1) mU/liter TSH, and at 180 sec, the best lower relative precision achieved was 80%. Thus, the sensitivity of the assay was improved by increasing the exposure time of the sections to TSH, but with a resultant loss of relative precision.
D000818:Animals; D000906:Antibodies / Q000502:physiology*; D001681:Biological Assay; D004305:Dose-Response Relationship, Drug; D004306:Dose-Response Relationship, Immunologic; D006168:Guinea Pigs; D006801:Humans; D006980:Hyperthyroidism / Q000276:immunology; D007074:Immunoglobulin G / Q000494:pharmacology; D018828:Immunoglobulins, Thyroid-Stimulating; D013961:Thyroid Gland / Q000502:physiology*; D013972:Thyrotropin / Q000494:pharmacology*; D013997:Time Factors
D000906:Antibodies; D007074:Immunoglobulin G; D018828:Immunoglobulins, Thyroid-Stimulating; D013972:Thyrotropin