Influence of ovariectomy and estrogen and/or progesterone treatment on pituitary and plasma lh and prolactin levels in female hamsters

Ovariectomy in adult female hamsters caused a highly significant elevation in pituitary luteinizing hormone (LH) and a highly significant reduction in pituitary prolactin levels. Likewise, loss of the ovaries was followed by a rise in plasma levels of LH while plasma prolactin titers dropped. Treatment of ovariectomized hamsters with estrogen (E) or progesterone (P), alone or in combination, did not greatly influence LH or prolactin levels in the pituitary. Whereas P, when administered alone or with E, returned plasma LH levels to normal, E by itself had no effect on LH levels in ovariectomized hamsters. Neither E nor P had any influence on the reduced plasma prolactin levels in ovariectomized female hamsters.