Background:Thyroid stimulating hormone (TSH, thyrotropin) in dogs is similar in function to TSH found in other mammalian species, including humans. It is a glycoprotein produced by the anterior pituitary gland. Through its action on the thyroid gland, it plays a major role in maintaining normal circulating levels of the iodothyronines, T4 and T3. The production and secretion of TSH is controlled by negative feedback from circulating T4 and T3, and by the hypothalamic hormone TRH (thyrotropin releasing hormone). The TSH molecule is composed of two nonidentical subunits, α and β, that are bound together in a noncovalent manner. Within a species, the TSH α subunit is structurally identical to the α subunits of the related glycoprotein hormones (LH, FSH and chorionic gonadotropin). The β subunit of TSH and the β subunits of the related hormones are structurally hormone-specific, and account for their unique biological activities. Hypothyroidism is considered to be a common endocrine disorder in dogs, whereas hyperthyroidism in this species is nearly unknown. Dogs mostly suffer from primary hypothyroidism, involving impaired production of the thyroid hormones, T4 and T3. In this condition, elevated TSH levels are expected. Secondary or tertiary hypothyroidism, where thyroid hormone production is low as a consequence of hypothalamic or pituitary disease, is believed to account for less than 5% of canine hypothyroidism cases. In the latter conditions, decreased levels of TSH would be expected. Usually, hypothyroidism in dogs is suspected on the basis of clinical history and the presence of decreased levels of thyroid hormones. However, suppressed thyroid hormone levels are nonspecific indicators of the disease, since they are often observed in nonthyroid illnesses. The evaluation of thyroid function and the diagnosis of hypothyroidism in dogs can be greatly improved through the use of the valid assay for the determination of canine TSH.
Description:
The test kit is a solid phase enzyme immunometric assay (ELISA) in the microplate format with liquid phase incubation for the quantitative measurement of canine TSH in serum or EDTA plasma samples. The microplate is coated with anti-TSH IgG. Calibrators and samples are pipetted into the antibody coated microplate, followed by addition of incubation buffer. Afterwards, a horseradish peroxidase-labeled antibody is added. During a two hour incubation sandwich complexes consisting of the two antibodies and the canine TSH is formed. Nonreactive components are removed by a washing step. A chromogenic substrate, TMB (3,3',5,5'-Tetra-Methyl-Benzidine), is added to all wells. During a 30 minutes incubation, the substrate is converted to a colored end product (blue) by the bound enzyme. Enzyme reaction is stopped by dispensing hydrochloric acid as stop solution (change from blue to yellow). The color intensity is direct proportional to the concentration of canine TSH present in the sample. The optical density (OD) of the color solution is measured with a microplate reader at 450 nm.
Product features:
The kit contains reagents for 96 determinations;
Microtiter plate consisting of 12x8 (breakapart);
Microtiter plate reader at 450 nm;
Analytical sensitivity: 0,049 ng/mL.
