Date of Award


Document Type


Degree Name

Master of Science (MS)




Structural luteolysis (SL) in the golden hamster (Mesocricetus auratus) is a remarkable event. The corpus luteum (CL) virtually disappears during a time span of 42 hours. SL begins around 0600 hours on day three of the cycle and is essentially complete by 2400 hours on day four of the cycle.

The purpose of this study was to determine when SL in the golden hamster actually begins and secondly to determine the way in which the three cell types involved in SL are depleted. The three cell types in question include luteal cells, endothelial cells, and neutrophils.

This study employed two separate In Situ techniques. The first technique incorporates biotinylated nucleotides onto the ends of fragmented genomic DNA. Since the fragmentation of DNA is the biochemical hallmark of apoptosis, labeling the fragmented DNA greatly enhances the detection of apoptotic cells in paraffin embedded tissue sections. Apoptag" which utilizes digoxigenin conjugated dUTP is also used in this study. This system proves to be highly valuable in the detection of apoptotic cells due to low background staining and extremely consistent results. In both of these systems nuclei which contain fragmented DNA stain brown.

Ovaries were collected at nine different time frames throughout the four day estrus cycle. Ovaries from a minimum of three animals were harvested for each time frame. Serial sections of three to four microns were then subjected to the two separate techniques.

The results of this study indicate that SL begins at 0600 hours on day three of the cycle, and is marked by a large infiltration of neutrophils. Following this neutrophilic infiltration there is a marked increase in apoptotic activity throughout the CL. Interestingly, in this model of study all three cell types involved, die by the process of apoptosis. The fact that apoptosis is the mode of cell death is important, since it does not elicit an intense inflammatory response