Activity of progesterone and anti-progestins in a rat mammary primary cell culture system

In Vitro Screening of Exogenous Factors for Human Neural Stem/Progenitor Cell Proliferation Using Measurement of Total ATP Content in Viable Cells

One of the newest and most promising methods for treating intractable neuronal diseases and injures is the transplantation of ex vivo-expanded human neural stem/progenitor cells (NSPCs). Human NSPCs are selectively expanded as free-floating neurospheres in serum-free culture medium containing fibroblast growth factor 2 (FGF2) and/or epidermal growth factor (EGF); however, the culture conditions still need to be optimized for performance and cost before the method is used clinically. Here, to improve the NSPC culture method for clinical use, we used an ATP assay to screen the effects of various reagents on human NSPC proliferation. Human NSPCs responded to EGF, FGF2, and leukemia inhibitory factor (LIF) in a dose-dependent manner, and the minimum concentrations eliciting maximum effects were 10 ng/ml EGF, 10 ng/ml FGF2, and 5 ng/ml LIF. EGF and LIF were stable in culture medium without NSPCs, although FGF2 was degraded. In the presence of human NSPCs, however, FGF2 and LIF were both degraded very rapidly, to below the estimated minimum concentration on day 3, but EGF remained above the minimum concentration for 5 days. Adding supplemental doses of each growth factor during the incubation promoted human NSPC proliferation. Among other supplements, insulin and transferrin promoted human NSPC growth, but progesterone, putrescine, selenite, D-glucose, and lactate were not effective and were cytotoxic at higher concentrations. Supplementing with conditioned medium from human NSPCs significantly increased human NSPC proliferation, but using a high percentage of the medium had a negative effect. These findings suggest that human NSPC culture is regulated by a balance in the culture medium between decreasing growth factor levels and increasing positive or negative factors derived from the NSPCs. Thus, in designing culture conditions for human NSPCs, it is useful to take the individual properties of each factor into consideration.

Mouse bioassay for in vivo screening of oestrogen and progesterone antagonists

This study tested and compared the anti-proliferative and proliferative activities of two anti-oestrogens and three anti-progestins on four separate mouse model systems: young intact and adult ovariectomized (OV-X) females, and young intact and adult castrated males. Pure steroidal anti-oestrogen ICI 182,780 (ICI) decreased mammary and uterine growth stimulated by endogenous hormones in young intact females and by exogenous hormones [progesterone (Prog), 17beta-oestradiol (E) or E plus Prog] in both young intact and adult ovariectomized (OV-X) females. Non-steroidal anti-oestrogen EM-800 (EM), on the other hand, had no effect on mammary and uterine growth stimulated by endogenous hormones in young intact females and in adult OV-X females. Uterine growth was even stimulated by EM alone, and a combination of EM plus Prog not only stimulated uterine growth but also mammary growth (an oestrogenic agonistic activity). However, EM showed anti-oestrogenic activities in both mammary and uterine tissues in females treated with E or E plus Prog. In males, ICI and EM decreased mammary growth stimulated by exogenous hormones (E or E plus Prog) in both young intact and adult castrated animals. In young intact, but not in adult castrated males, ICI increased seminal vesicle growth affected by both endogenous and exogenous (Prog, E or E plus Prog) hormones. EM, on the other hand, decreased seminal vesicle weights in E or E plus Prog and increased its weights in Prog-treated young intact males. Thus, under certain conditions EM possess mixed agonist and antagonist activity in the mammary gland, uterus and seminal vesicles. Norethindrone acetate (NA)-stimulated mammary growth was decreased by anti-progestins onapristone (ON), RU 46556 (RU), and RU 38486 (MI) by 34-59% in females and by 35-93% in males. Uterine weights of NA-treated females were decreased by ON and RU by 29-55% but not by MI. In NA-treated young intact males, seminal vesicle weights were stimulated by RU (by 63%) and not affected by ON and MI. In NA-treated adult castrated males, seminal vesicle weights were decreased by ON, increased by RU and not affected by MI. The results obtained in these and our earlier studies show clearly that mouse four-model systems could serve as in vivo tool for the detection of steroid hormone agonist and antagonist activities of natural and man-made chemicals.

Effects and metabolism of steroid hormones in human neuroblastoma cells

The development of the central nervous system is influenced by sex steroids and by their metabolites. However, little information on the possible effects of steroid hormones on neuroblastoma cells is available. Human neuroblastoma cell lines have been used as a model of human neuroblasts in vitro to study the metabolism of steroid hormones; in addition, the effects of steroids and steroid antagonists on neuroblastoma cell growth have also been investigated. The results obtained show that SH-SY5Y human neuroblastoma cells may actively metabolize testosterone and progesterone to their respective 5 alpha-reduced metabolites and that differentiation of neuroblastoma cells is paralleled by a significant increase in expression of the type-1 5 alpha-reductase and of the formation of steroid metabolites. All these data are suggestive of a potential role of steroid 5 alpha-reduced metabolites in the biology of neuroblastoma cells. Studies performed to analyze the role of steroid hormones on neuroblastoma cell proliferation show that progesterone at low doses may induce minor stimulation, and at higher doses, a toxic effect on the neuroblastoma cell line SK-N-SH is seen. Moreover, the antiprogestin 17 beta-hydroxy-11 beta-(4-dimethylamino-phenyl-1)-17-(prop-1-ynyl)estra-4,9-dien+ ++-3-one (RU486) decreases the proliferation of these cells in a dose-dependent manner. The effect of RU486 is not antagonized by either progesterone or dexamethasone, a result that seems to exclude the action of RU486 via classic intracellular steroid hormone receptors.