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Induced luteal regression in the primate: evidence for apoptosis and changes in c-myc protein
H M Fraser1, S F Lunn, G M Cowen
1MRC Reproductive Biology Unit, Centre for Reproductive Biology, Edinburgh, UK.
Abstract:
There is increasing molecular evidence that apoptosis is involved in the process of structural luteal regression in non-primate species. Apoptosis is dependent upon the activation of certain proto-oncogenes and c-myc protein has an important regulatory role in this process in some cell types. The aim of the present study was to determine the occurrence and localisation of c-myc protein within the primate corpus luteum, determine changes during induction of luteal regression and examine the corpora lutea for morphological evidence of apoptosis. Ovaries were studied from marmoset monkeys in the late follicular, and in the early, mid and late luteal phases. Luteal regression was induced either by treatment with prostaglandin F2 alpha analogue or GnRH antagonist administered during the mid luteal phase and ovaries obtained 24 and 48 h later. Immunocytochemistry was performed using a monoclonal antibody to the c-myc protein. In pre-ovulatory follicles positive staining was found in the nucleus of a few granulosal cells and in the cytoplasm of thecal cells. c-myc was present in all corpora lutea where it was localised predominantly in the cytoplasm. In early corpora lutea, scattered cells with intense staining were observed in the presence of a majority of moderately or weakly stained cells. In the mid and late luteal phases, corpora lutea were uniformly moderately stained for c-myc. Following induction of luteal regression, regression, nuclear degeneration with condensation and fragmentation indicative of apoptosis was observed. In other luteal cells, increased membranes suggested necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
The c-myc protein is present in the primate corpus luteum and its levels change during luteal regression. This study observed apoptosis during luteal regression, suggesting c-myc
Area of Science:
- Reproductive Biology
- Cellular Biology
- Endocrinology
Background:
- Apoptosis, a programmed cell death, is increasingly recognized in the structural regression of the corpus luteum in non-primate species.
- Proto-oncogenes, such as c-myc, play a regulatory role in apoptosis in various cell types.
- Understanding c-myc's role in primate luteal regression is crucial for reproductive research.
Purpose of the Study:
- To investigate the presence and location of c-myc protein in the primate corpus luteum.
- To analyze changes in c-myc protein expression during induced luteal regression.
- To identify morphological signs of apoptosis in the primate corpus luteum during regression.
Main Methods:
- Ovaries from marmoset monkeys were collected during different reproductive phases (follicular, early, mid, and late luteal).
- Luteal regression was induced using prostaglandin F2 alpha analogue or GnRH antagonist.
- Immunocytochemistry with a monoclonal antibody to c-myc protein was employed to detect its presence and localization.
Main Results:
- c-myc protein was detected in the primate corpus luteum, primarily in the cytoplasm, with varying staining intensity across luteal phases.
- Following induced luteal regression, morphological evidence of apoptosis, including nuclear condensation and fragmentation, was observed.
- Necrosis was also indicated in some luteal cells during regression.
Conclusions:
- c-myc protein is present in the primate corpus luteum and its expression changes during the luteal phase and induced regression.
- The findings support the involvement of apoptosis in primate luteal regression, with potential regulation by c-myc.
- Further research is warranted to fully elucidate the role of c-myc in primate corpus luteum function and regression.