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(462) APOPTOSIS INDUCED BY SERUM DEPRIVATION IN RAT LUTEAL CELLS. Goyeneche, Alicia1,2, Telleria, Carlos1,2, Gibori, Geula1, 1 Department of Physiology and Biophysics, Chicago, IL2 Institute of Medicine and Experimental Biology, Mendoza, Argentina ABSTRACT- Luteolysis is characterized by a decrease in progesterone production (functional regression) and a reduction in luteal mass (structural regression) associated to apoptosis. However, apoptosis associated with luteal demise is not a synchronized process as could be observed in other ovarian structures such as the granulosa cell layer of follicles undergoing atresia. Therefore, only methods for in situ detection of apoptotic cells (such as TUNEL), have to be used in the corpus luteum. This is because the number of cells undergoing apoptosis at any given time in this transient endocrine gland is not high enough for evaluation of genomic DNA fragmentation in agarose gels. However, we have previously demonstrated that if the corpus luteum at any age is placed in vitro in serum-free conditions, extensive genomic DNA fragmentation can be detected. In the present investigation, we utilized SV40 transformed luteal cells (GGCL) to determine if they can be driven to the apoptotic pathway, and, if so, whether they can be used as an experimental model to study the signal transduction mechanisms involved in luteal cell survival induced by prolactin. GGCL cells were cultured for 48 h in culture media containing 10% fetal bovine serum. Then, the media was removed and replaced with fresh media lacking serum. Under these conditions, cells underwent extensive apoptosis as evaluated by DNA fragmentation in agarose gels. Apoptosis induced by serum starvation was partially prevented by the presence of curcumin, a broad inhibitor of the nuclear factor-kappa B signal transduction pathway, or by MG132, an inhibitor of the proteasome 26. GGCL cells permanently transfected with the long form of the prolactin receptor underwent apoptosis similarly to the untransfected cells after 24-48 h of serum deprivation, and the addition of 1 KEY WORDS: Corpus Luteum, Ovary, Apoptosis, Prolactin |
g/ml ovine prolactin to the media was capable to significantly decrease DNA fragmentation induced by serum starvation. In conclusion, we have demonstrated that the luteal cell line GGCL can be used as an experimental model to study the process of apoptosis in luteal cells as well as the antiapoptotic signaling pathways triggered by prolactin. Supported by NIH Grants FIRCA 1R03 TW01049-03 (CMT, GG) and HD11119 (GG).