Progesterone levels following treatment of seasonally anoestrous ewes with synthetic LH-releasing hormone.
Plasma progesterone determinations were carried out on blood samples collected daily from Clun Forest ewes during the normal oestrous cycle and also after administration of LH-releasing hormone (LH-RH) during seasonal anoestrus. Levels of plasma progesterone at oestrus ranged from 0.1 to 0.5 ng/ml and luteal phase levels from 3 to 6 ng/ml. Levels found during seasonal anoestrus were within the range of those observed as oestrus. Following treatment with LH-RH, there was in increase in the plasma LH level in a-l cases and ovulation occurred in twenty-three out of twenty-seven treated ewes. In the animals which ovulated, the plasma progesterone concentration either remained basal (eighteen animals) or rose to a lower level (2 ng/ml is greater than) than that found during the luteal phase of the cycle.
D000818:Animals; D004971:Estrus; D005260:Female; D006041:Goats / Q000276:immunology; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D007601:Jugular Veins; D007986:Luteinizing Hormone / Q000097:blood; D010060:Ovulation / Q000187:drug effects; D011247:Pregnancy; D011374:Progesterone / Q000097:blood*; D011817:Rabbits / Q000276:immunology; D012756:Sheep / Q000097:blood*; D013997:Time Factors
D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D007986:Luteinizing Hormone