Abstract
The recent demonstrations that Mullerian inhibiting substance (MIS) is present in embryonic chick ovaries ( P. K. Hutson, H. Ikawa, and P. K. Donahoe (1981). J. Pediatr. Surg. 16, 822–827), and that exogenous diethylstilbestrol does not significantly inhibit MIS secretion from feminized testes ( Hutson et al. (1982) J. Pediatr. Surg. 17, 953–959), suggest that ovarian estrogens protect the female left Mullerian duct from MIS-induced regression. The possibility exists, however, that ovarian MIS may be inactive. This study was designed to see if interference with estrogen action in ovo would allow MIS to cause regression of the female left Mullerian duct. The “antiestrogens,” tamoxifen and LY117018, had little effect on the female Mullerian ducts unless given in high doses or with added testosterone (>0.1 mg). Two compounds known to inhibit estrogen synthesis, aminoglutethimide and 4-hydroxyandrostenedione, had no effect on their own, even in high dose (<1.0 mg/egg). However, when administered together (0.5 mg each) there was significant disappearance of the lower ends of both Mullerian ducts. Norethindrone, which has been described recently as an aromatase inhibitor ( Y. Osawa, C. Yarborough, and V. Osawa (1982). Science (Washington, D.C.) 215, 1249–1251) caused partial regression of the upper end of the left Mullerian duct as well as complete loss of the lower ends of both ducts in the female. These results suggest that the steroid environment is a critical factor in the response of the Mullerian ducts to MIS, and that estrogen blockage may allow endogenous MIS from the ovary to induce partial regression of the Mullerian ducts in the female chick embryo.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.