Effect of thyrotropin-releasing hormone (TRH) on bovine plasma thyroxine levels at 18.5 and 35 C.
Six mature nonlactating Holstein cows were subjected to a test procedure of a sham period (saline injection) of 10 days that prededed and followed each 14 day TRH treatment period at 18.5 and 35 degrees. The objective of this study was to determine the effect of intramuscular injection of TRH (400D 35 DEGREES. The results indicate that im administration of TRH is effective in elevating plasma thyroxine levels at both 18.5 and 35 degrees, but the response is diminished after 7 days at 18.5 degrees and ineffective in sustaining or elevating plasma thyroxine levels in cattle after 6 days of TRH administration at 35 degrees.
D000818:Animals; D002417:Cattle / Q000502:physiology*; D005260:Female; D013696:Temperature; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*; D013974:Thyroxine / Q000097:blood*; D013997:Time Factors
D013973:Thyrotropin-Releasing Hormone; D013974:Thyroxine