Thyrotrophin releasing hormone and related peptides in canine tissues.
Thyrotrophin releasing hormone (TRH)-immunoreactive peptides have been quantified in canine serum, hypothalamus, liver, pancreas, adrenal, thyroid, prostate, testis, epididymis and semen by TRH radioimmunoassay, SP-Sephadex C-25 cation exchange chromatography, Sephadex G-10 exclusion chromatography and high pressure liquid chromatography. The total concentration of TRH and TRH-like peptides was highest in the hypothalamus, followed by liver, adrenal, pancreas, thyroid, prostate, epididymis, testis and serum. All of the TRH immunoreactivity (TRH-IR) within extracts of the hypothalamus was due to TRH. On the other hand, nearly all of the TRH-IR of extracts of liver, thyroid, prostate, epididymis, testis and semen was due to TRH-homologous peptides. Adrenal and pancreatic extracts contained a greater proportion of TRH in relation to the TRH-homologous peptides. Extracts of dog serum and semen were found to contain a TRH-binding substance which reduced the retention of added TRH by cation exchangers. The half-time of disappearance (t1/2) of synthetic TRH incubated at 23 degrees C in 10% (w/v) homogenates in 0.15 M-NaCl-0.05 M-phosphate buffer, pH 7.5, ranged from 22 +/- 10 (S.D.) min for liver to 120 +/- 58 min for thyroid. The short t1/2 for TRH added to dog liver homogenates contrasted with a previous report that dog liver is essentially free of TRH-degrading activity.
D000311:Adrenal Glands / Q000032:analysis; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004285:Dogs; D004822:Epididymis / Q000032:analysis; D007031:Hypothalamus / Q000032:analysis; D008099:Liver / Q000032:analysis; D008297:Male; D010179:Pancreas / Q000032:analysis; D010455:Peptides / Q000032:analysis*; D011467:Prostate / Q000032:analysis; D011863:Radioimmunoassay; D012661:Semen / Q000032:analysis; D013737:Testis / Q000032:analysis; D013961:Thyroid Gland / Q000032:analysis; D013973:Thyrotropin-Releasing Hormone / Q000032:analysis* / Q000097:blood
D010455:Peptides; D013973:Thyrotropin-Releasing Hormone