Fluctuation of the plasma TRH level in normal subjects in a 4-hour observation period.
Radioimmunoassayable TRH and TSH were measured in plasma samples taken at 5 min intervals for 4 hr (2100-0200 hr) from 4 normal male subjects. Three subjects showed a TSH surge at 2135 hr, 2455 hr and 0150 hr, respectively. The mean plasma TRH level of the 4 subjects was 10.3-11.7 pg/ml. Plasma TRH showed random fluctuation, which did not coincide with the nocturnal increase in plasma TSH.
D000328:Adult; D002940:Circadian Rhythm; D006801:Humans; D008297:Male; D011863:Radioimmunoassay; D013972:Thyrotropin / Q000097:blood*; D013973:Thyrotropin-Releasing Hormone / Q000097:blood*
D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin