Linked Life Data

8185939

Source:http://linkedlifedata.com/resource/pubmed/id/8185939

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1994-6-23
pubmed:abstractText
The structure of oocytes aspirated from the dominant and its subordinate follicles was investigated from the achievement of follicular dominance to ovulation. Ovulation was induced in 18 heifers and 5 cows by injection of cloprostenol at days 8-14 (day 0 = day of ovulation), and follicular development was monitored by ultrasonography. The animals were slaughtered at days 3-11, but animals slaughtered on days 8-11 were given a second injection of cloprostenol at day 7 to allow ovulation of the dominant follicle of the first follicular wave. Oocytes were aspirated from the dominant (largest) and two largest subordinate follicles and processed for transmission electron microscopy, whereas the follicular fluids were analyzed for concentrations of estradiol-17 beta (E2) and progesterone (P4). Dominant follicular growth was associated with increase in the concentration of E2 and P4 in the follicular fluid, which was E2-dominated. From days 3-7, the dominant oocytes had pronounced junctional contacts with the cumulus cells and a nonundulating nuclear envelope but showed an increase in the number of lipid droplets and a decrease in the size of Golgi complexes, the size of cortical granule clusters, and the number of microvilli stacks. After cloprostenol injection on day 7, but before the anticipated LH surge, the dominant oocytes showed a reduced oocyte-cumulus contact, vacuolization of the nucleolus, undulation of the nuclear envelope, and dispersal of the mitochondrial clusters. The morphological alterations occurring in the dominant oocytes before the anticipated LH surge are suggested to be a prerequisite for the oocyte to achieve the competence to undergo final maturation. Subordinate follicles ceased growing at about days 3-4 and their follicular fluid had low E2:P4 ratio or was P4-dominated. Subordinate oocytes displayed degenerative features in their cumulus investment and nuclear activation and maturation especially after day 5. The structural changes associated with oocyte degeneration showed similarities with the processes seen before and during final maturation of the dominant oocytes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1040-452X
pubmed:author
pubmed:issnType
Print
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
335-44
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Oocyte morphology in dominant and subordinate follicles.
pubmed:affiliation
Department of Anatomy and Physiology, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't