Kawashima M, Kamiyoshi M, Tanaka K, Hattori M, Wakabayashi K
J Reprod Fertil. 1981 Nov;63(2):567-70. doi: 10.1530/jrf.0.0630567.
LH-releasing activity of the hypothalamus in non-laying hens following the injection of progesterone was increased in hens that had been treated with oestradiol 4 h earlier. Short-term priming with oestradiol may be effective in increasing the responsiveness of the hen hypothalamus to progesterone.