Plasma luteinizing hormone levels throughout development and relative to ovulation in pinealectomized hens (Gallus...

The role of the pineal gland in the reproductive endocrinology of the hen was examined. Chicks were pinealectomized or sham-operated at 2-3 days of age and the developmental LH profile, body weights, and age of lay of the first egg were compared to those of unoperated controls. There were no differences in any of the parameters measured throughout development. When the birds were mature, LH levels during the evening prior to a first ovulation of the sequence were also compared among the three groups of hens. No differences were found between the pinealectomized and unoperated-control hens. The sham-operated animals showed significant differences from the control hens at three time periods but differed from the pinealectomized group at only one time period. It is possible that the somewhat unusual LH profile exhibited by the sham-operated group is a result of the surgery.