The fragmentation pathways of five estrogens (estradiol, estrone, equilin sulfate, 17 a-dihydroequilin sulfate and equilenin sulfate) have been studied with high resolution and high mass accuracy using electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF/MS) in the negative ion mode. Molecular weights were obtained from [M-H](-) ions in the product ion spectra. The results indicate that the five structurally similar estrogens have similar fragmentation pathways. Using their stable isotope forms as internal reference compounds, the accurate mass and composition of the fragment ions were determined. During collision-induced dissociation (CID), cleavage is initiated by loss of oxygen atoms from carbon-17, after which D and C rings cleave sequentially and rearrange to finally form stable conjugate structures with highly abundant characteristic fragment ions at m/z 183 (accompanied by m/z 181), m/z 169 and m/z 145 (accompanied by m/z 143). Understanding these characteristic fragmentation pathways of estrogens will be helpful in identifying the structures of steroid hormones in general.

OBJECTIVE：To study the toxic effect of the extract from Tripterygium hypoglaucum on pregnant animal and embryo-fetal development . METHODS ：Successfully mated New Zealand female rabbits were randomly divided into solvent control group，positive control group （cyclophosphamide，20 mg/kg）and T. hypoglaucum extract high-dose ，medium-dose and low- dose groups（15.0，7.50，3.75 g/kg，by the amount of crude drug ）according to their body weight ，with 18 rabbits in each group at least. The female rabbits in solvent control group and T. hypoglaucum extract groups were given water or the corresponding T. hypoglaucum extract solution from 6th to 18th day of pregnancy ，5 mL/kg，once a day. Positive control group was given cyclophosphamide subcutaneously into the neck from 10th to 13th day of pregnancy ，1 mL/kg，once a day. According to the related requirements of Technical Guidelines for the Study of Drug Reproductive Toxicity ，the general situation ，body weight ，body weight increase and food intake of female rabbits were observed and recorded during the experiment ，and euthanasia was carried out on 28th day of pregnancy ；the relative indexes of main organs ，fetal uterus ，placenta uterus ，placenta，ovary，implantation gland ， absorption fetus ，stillbirth，live fetus and corpus luteum were observed and recorded after anatomy ；the relative indexes of body weight，appearance，visceral and skeletal alterations of the fetus were detected . RESULTS ：Compared with solvent control group ， the body weight ，body weight increase ，food intake ，main organs ，pregnancy of pregnant rabbits ，as well as reproductive function，embryo formation ，fetal growth and development ，appearance，visceral and skeletal development indexes in T. hypoglaucum extract groups had no significant abnormal changes （P＞0.05）；above indexes in the positive control group had significant changes （P＜0.05），and significant maternal toxicity and embryotoxicity were found. CONCLUSIONS ：T. hypoglaucum extract 15.00-3.75 g/kg（by the amount of crude drug ）have no significant maternal toxicity ，embryotoxicity or fetal development toxicity to New Zealand rabbits.