cytochrome-c-t and cetrorelix

Exposure to chemotherapy causes various adverse effects on the ovaries including premature ovarian failure and infertility. GnRH antagonist cetrorelix could reverse the ovarian damage during chemotherapy, but the mechanism remains unclear. The objectives of this study were to examine the role of the cetrorelix for prevention of mitochondria-dependent apoptosis in granulosa cells of rats during the treatment with cyclophosphamide(Cy), if the mitochondria-dependent apoptotic process was involved.. Female SD rats were injected with cetrorelix before and after administration of saline, or Cy. Main outcome measures were the apoptotic indexes, serum hormones, ultrastructure of granulosa cells, mitochondrial membrane potential, the kinetics of cytochrome c (Cyt-c) processing in cells, and apoptotic markers.. The ovarian apoptotic indexes as shown by TUNEL assay were reduced by cetrorelix pretreatment and the rats regained normal hormonal profile. The ultrastructure and JC-1 fluorescence intensity assessments showed cetrorelix pretreatment inhibited mitochondrial dysfunction in granulosa cells induced by chemotherapy. Western blot analysis showed that cetrorelix suppressed the release of Cyt-c from mitochondria to cytoplasm. Meanwhile, cetrorelix pretreatment expressed less Bax, caspase-3 and Cyt-c in granulosa cells compared with chemotherapy alone.. Cetrorelix could reduce the apoptosis in granulosa cells through inhibiting mitochondria-dependent apoptosis triggered by chemotherapy.

Topics: Animals; Antineoplastic Agents, Alkylating; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Cyclophosphamide; Cytochromes c; Cytoplasm; Estradiol; Female; Gonadotropin-Releasing Hormone; Granulosa Cells; Hormone Antagonists; Immunohistochemistry; Membrane Potential, Mitochondrial; Mitochondria; Progesterone; Random Allocation; Rats; Rats, Sprague-Dawley

The role of pituitary gonadotropins in the regulation of spermatogenesis has been unequivocally demonstrated, although, the precise mechanism of this regulation is not clearly understood. Previous studies have shown that specific immunoneutralization of LH/testosterone caused apoptotic cell death of meiotic and post-meiotic germ cells while that of FSH resulted in similar death of meiotic cells. In the present study, the death process of germ cells has been characterized by depleting both FSH and testosterone by administering two different potent GnRH antagonists, Cetrorelix and Acyline to both rats and mice. Pro-survival factors like Bcl-2 and Bcl-x/l were unaltered in germ cells due to GnRH antagonist treatment, although a significant increase in several pro-apoptotic markers including Fas and Bax were evident at both protein and RNA levels. This culminated in cytochrome C release from mitochondria and eventually increase in the activity of caspase-8 and caspase-3. These data suggest that both extrinsic and intrinsic apoptotic death pathways are operative in the germ cells death following decrease in FSH and testosterone levels. Multiple injections of GnRH antagonist resulted in complete disappearance of germ cells except the spermatogonial cells and discontinuation of the treatment resulted in full recovery of spermatogenesis. In conclusion our present data suggest that the principal role of FSH and testosterone is to maintain spermatogenic homeostasis by inhibiting death signals for the germ cells.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Biomarkers; Caspases; Cytochromes c; Cytoplasm; Death Domain Receptor Signaling Adaptor Proteins; Follicle Stimulating Hormone; Gonadotropin-Releasing Hormone; Male; Mice; Organ Size; Protein Structure, Quaternary; Rats; Rats, Wistar; Spermatozoa; Testis; Testosterone

The distribution of the steroidogenic acute regulatory protein (StAR) inside thecal and granulosa-lutein cells of human corpus luteum (CL) was assessed by immunoelectron microscopy. We found greater levels of StAR immunolabeling in steroidogenic cells from early- and mid-than in late luteal phase CL and lower levels in cells from women treated with a GnRH antagonist in the mid-luteal phase. Immunoelectron microscopy revealed significant levels of StAR antigen in the mitochondria and in the cytoplasm of luteal cells. The 30 kDa mature StAR protein was present in both mitochondria and cytosol (post-mitochondrial) fractions from homogenates of CL at different ages, whereas cytochrome c and mitochondrial HSP70 were detected only in the mitochondrial fraction. Therefore, we hypothesized that either appreciable processing of StAR 37 kDa pre-protein occurs outside the mitochondria, or mature StAR protein is selectively released into the cytoplasm after mitochondrial processing. The presence of mature StAR in the cytoplasm is consonant with the notion that StAR acts on the outer mitochondrial membrane to effect sterol import, and that StAR may interact with other cytoplasmic proteins involved in cholesterol metabolism, including hormone sensitive lipase.

Topics: Blotting, Western; Carrier Proteins; Cytochromes c; Cytoplasm; Female; Gonadotropin-Releasing Hormone; HSP70 Heat-Shock Proteins; Humans; Luteal Cells; Luteal Phase; Membrane Proteins; Microscopy, Immunoelectron; Mitochondria; Phosphoproteins