Plasma LH progesterone concentrations in the turkey hen during the ovulatory cycle.

Progesterone and luteinizing hormone (LH) were measuured in the plasma of Large White turkey hens at frequent intervals during the ovulatory cycle and during the periods when ovulations did not occur. The hormones were quantitated at the beginning and the end of the reproductive season to follow the change in patterns and concentrations of these hormones. Radioimmunoassay procedures were used to assay both hormones. Both progesterone and LH reached a peak amount at about 8 to 2 hours before ovulation. At no time did the progesterone peak precede that of LH. On the other hand, the peak of progesterone was observed to last somewhat longer than the LH peak. Progesterone and LH concentrations demonstrated no peak during the non-ovulatory periods. The patterns of both hormones at the end of the reproductive season was about the same as at the beginning of the season, but with lower concentrations.