The Ability of Norgestomet Impregnated Poly(dimethylsiloxane) Implants to Maintain Pregnancy Subsequent to Ovariectomy
Poly(dimethylsiloxane) has been used to deliver steroids to animals since the 1960s and a commercial poly(dimethylsiloxane) based delivery system for estradiol is currently available for growth enhancement. Recent data collected in our laboratory demonstrated that poly(dimethylsiloxane) implants impregnated with norgestomet, a synthetic progestin, were capable of maintaining pregnancy in ovariectomized heifers. In the absence of an exogenous source of a progestin, ovariectomy would cause abortion or premature parturition in cattle. Ovariectomized heifers implanted with poly(dimethylsiloxane)/norgestomet implants had pregnancy rates similar to treated females not ovariectomized. Removal of the poly(dimethylsiloxane)/norgestomet implants late in gestation permitted the heifers to calve and offspring born were normal.
KeywordsMammary Gland Corpus Luteum Ethylene Glycol Methacrylate Secretion Rate Testosterone Concentration
Unable to display preview. Download preview PDF.
- 3.D. M. Long, Jr. & J. Folkman, U.S. Patent #3,279,996 (1966).Google Scholar
- 5.V. Lee & J. R. Robinson in: “Sustained and Controlled Release Drug Delivery Systems,” J. R. Robinson, Ed., Marcel Dekker, Inc., New York, 1985.Google Scholar
- 6.D. J. Kesler, Proc. Polym. Mat. Sci. Eng., 57, 408 (1987).Google Scholar
- 7.D. J. Kesler in: “Applied Bioactive Polymeric Materials,” C. G. Gebelein, C. E. Carraher, Jr. & V. Foster, Eds., Plenum Publishing Co., New York, 1989.Google Scholar
- 9.T. R. Troxel & D. J. Kesler, Univ. of Illinois Circular 1205 (1982).Google Scholar
- 11.T. R. Troxel, G. F. Cmarik, R. S. Ott & D. J. Kesler, J. Anim. Sci., 59, (Suppl. 1), 322 (1984).Google Scholar
- 12.D. J. Kesler & M. F. Gibson, Proc. IV Int. Symp. Vet. Lab. Diagnosticians, p. 379 (1986).Google Scholar
- 14.D. J. Kesler, R. C. Peterson, R. E. Erb & C. J. Callahan, J. Anim. Sci., 42, 918 (1976).Google Scholar