Collu R, Ruisseau P D, Taché Y, Ducharme J R
Endocrinology. 1977 May;100(5):1391-3. doi: 10.1210/endo-100-5-1391.
The concentration of thyrotropin-releasing hormone (TRH) was measured by specific radioimmunoassay in three different brain regions of rats sacrificed every 4 h over a 24 h period. TRH concentration reached a zenith at 1200 h both in the hypothalamus and the amygdala but did not vary in the forebrain. These results indicate that a nyctohemaral variation of TRH levels exists in hypothalamic and extrahypothalamic brain areas.