title: Identification at the onset of luteolysis of follicles capable of ovulation in the ewe.
abstract: Follicles of various sizes at the surface of the ovary were ablated by electrocautery at the time of cloprostenol-induced luteolysis in ewes and the interval from cloprostenol treatment to the onset of the LH surge determined as an index of the time from luteolysis to ovulation. When follicles 2-4 mm or greater than 4 mm diameter remained in the ovaries, the interval from cloprostenol treatment to the onset of the LH surge was similar to that in sham-operated (control) ewes (55-60 h), whereas when the only follicles remaining were less than 2 mm, the interval was extended by 24 h (P less than 0.05). This study demonstrates that follicles capable of ovulating can be selected from those greater than or equal to 2 mm diameter at luteolysis, emphasizing the flexibility of the sheep ovary in its final selection of the ovulatory follicle.
mesh_terms: D000818:Animals; D003008:Cloprostenol / Q000494:pharmacology; D003338:Corpus Luteum / Q000187:drug effects / Q000502:physiology*; D005260:Female; D007986:Luteinizing Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000033:anatomy & histology / Q000502:physiology*; D010060:Ovulation; D011374:Progesterone / Q000097:blood; D012756:Sheep / Q000502:physiology*; D013997:Time Factors
chemical_list: D003008:Cloprostenol; D011374:Progesterone; D007986:Luteinizing Hormone