Back to Search
Start Over
Characterization of large luteal cells and their secretory granules during the estrous cycle of the cow.
- Source :
-
Biology of reproduction [Biol Reprod] 1992 Apr; Vol. 46 (4), pp. 535-45. - Publication Year :
- 1992
-
Abstract
- Large steroidogenic cells of the bovine corpora lutea were evaluated for morphological changes on Days 3, 7, 11, 14, 17, and 19 of the estrous cycle. Large cells were readily identified by size (25-50 microns diameter), numerous mitochondria, and the presence of dense secretory granules (150-300 nm in diameter). These granules were found in a discrete cluster and were not dispersed throughout the cytoplasm. Only 3% of the large cells contained a cluster of granules on Day 3. The percentage was highest during midcycle (Day 7, 84%; Day 11, 64%), dropped on Day 14 (26%), and was lowest on Days 17 (16%) and 19 (8%). Electron microscopic immunocytochemistry showed that oxytocin and neurophysin were co-localized in these granules on all days evaluated. As early as Day 14, large cells were observed with characteristics typical of regressing corpora lutea, i.e., a reduction in cells with secretory granules, large cytoplasmic lipid droplets, and swollen mitochondria with dense inclusions. However, since this was a time of the cycle when plasma concentrations of progesterone were very high, this corpus luteum is referred to as involutive rather than regressive. Our results may be summarized as follows: 1) from Day 7 to Day 14 there was a 69% decline in the number of large cells containing oxytocin-laden secretory granules. This occurred prior to the rise in uterine oxytocin receptors and the large luteolytic pulses of prostaglandin that reportedly occur after Day 14. The role of this apparent early release of oxytocin is not known. 2) Large steroidogenic luteal cells of the estrous cycle have morphological characteristics similar to those of large luteal cells during pregnancy. However, large luteal cells of the estrous cycle contain oxytocin whereas those of pregnancy are devoid of oxytocin.
- Subjects :
- Animals
Cattle
Corpus Luteum cytology
Corpus Luteum metabolism
Corpus Luteum physiology
Cytoplasmic Granules chemistry
Cytoplasmic Granules physiology
Female
Immunohistochemistry
Luteal Cells physiology
Luteal Cells ultrastructure
Microscopy, Electron
Mitochondria ultrastructure
Neurophysins analysis
Oxytocin analysis
Progesterone blood
Cytoplasmic Granules ultrastructure
Estrus physiology
Luteal Cells cytology
Subjects
Details
- Language :
- English
- ISSN :
- 0006-3363
- Volume :
- 46
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Biology of reproduction
- Publication Type :
- Academic Journal
- Accession number :
- 1576252
- Full Text :
- https://doi.org/10.1095/biolreprod46.4.535