Patterns of secretion of human chorionic gonadotrophin by superfused placental explants and the embryo--placental relationship following maternal use of medications

Control of cell proliferation by embryonal-origin factors

Embryogenesis can be paralleled and contrasted with cancerous cell proliferation; both embryogenesis and cancer are associated with extremely rapid cell proliferation. However, unlike cancer, embryogenesis is characterized by a delicate balance of proliferative and anti-proliferative processes. We have found two chromatographically separated fractions derived from human embryonal neural tissue extracts that significantly suppress the proliferation of human breast cancer cells. The reduction in cell number was time dependent, with maximal inhibition (70%) observed after 4 days of incubation while maintaining cell viability. The anti-proliferative effect was also evidenced by decreased [3H]-thymidine incorporation. Significant inhibition of proliferation of osteosarcoma, fibrosarcoma, and Balb/c 3T3 cell lines was also obtained with a low concentration of the active fractions. Embryonal factors inhibited mouse and rat cell lines, indicating cross-species effectiveness. The SDS-PAGE of the biologically active approximately 10.7 kDa region revealed several protein bands, while the biologically active approximately 4.5 kDa fraction contained only weakly stainable bands. Thus, the embryo contains factors that control the proliferation of malignant cells. These potent and possibly novel compounds should be investigated for their potential therapeutic role in cancer and other proliferative disorders.

Sites of female reproductive vulnerability: implications for testing and risk assessment

All reproductive toxicity testing, whether in vivo or in vitro, should be conducted with consideration of the ultimate use of the data for reproductive risk assessment and the protection of human reproductive health. In this review selected sites of vulnerability in the female reproductive system are identified. These sites of female reproductive vulnerability may be utilized for in vitro toxicity testing assays, and the data from assays may be employed in the hazard identification and hazard characterization steps necessary for reproductive risk assessment. Using biomarkers of female reproductive function derived from in vitro toxicity testing it is possible to define functions that characterize female fecundity. These characterizations of female fecundity may be used to quantitate reproductive risk in human populations.