TRH immunoreactivity in the thyroid gland.
Methanol extracts of dog and pig thyroid tissue contained considerable amounts of thyrotropin releasing hormone immunoreactivity (iTRH): 2.98 +/- 1.38 and 1.83 +/- 0.58 pmol/g thyroid wet weight, respectively (mean +/- SD). This iTRH was not due to ether extractable materials and behaved like TRH standard in dilution experiments, during gel filtration on Sephadex G-25 and during thin layer chromatography on a silica gel plate. Cation exchange chromatography on SP-Sephadex C-25 revealed that the iTRH in methanol extract was heterogeneous. However, part of the iTRH applied on the column was eluted as synthetic TRH: 0.209 +/- 0.046 and 0.052 +/- 0.021 pmol/g dog and pig thyroid, respectively. During incubation with rat serum, the SP-Sephadex purified iTRH disappeared in parallel with TRH. These studies indicate that the thyroid contains small amounts of iTRH which behaves identically to synthetic TRH.
D000818:Animals; D002850:Chromatography, Gel; D002855:Chromatography, Thin Layer; D004285:Dogs; D000432:Methanol / Q000494:pharmacology; D009929:Organ Size; D011863:Radioimmunoassay; D051381:Rats; D013552:Swine; D013961:Thyroid Gland / Q000032:analysis*; D013973:Thyrotropin-Releasing Hormone / Q000032:analysis* / Q000276:immunology
D013973:Thyrotropin-Releasing Hormone; D000432:Methanol