This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hayashi, K. Articles by Spencer, T. E. Search for Related Content PubMed PubMed Citation Articles by Hayashi, K. Articles by Spencer, T. E.

Neonatal Estrogen Exposure Disrupts Uterine Development in the Postnatal Sheep

Center for Animal Biotechnology and Genomics and Department of Animal Science, Texas A&M University, College Station, Texas 77843-2471

Address all correspondence and requests for reprints to: Thomas E. Spencer, Center for Animal Biotechnology and Genomics, 442 Kleberg Center, 2471 TAMU, Texas A&M University, College Station, Texas 77843-2471. E-mail: tspencer{at}tamu.edu.

Postnatal development of the ovine uterus between birth and postnatal day (PND) 56 involves budding differentiation of the endometrial glandular epithelium from the luminal epithelium (LE) followed by extensive coiling and branching morphogenesis of the tubular glands. To determine the short- and long-term effects of estrogen on neonatal ovine uterine development after PND 14, neonatal sheep were randomly assigned at birth (PND 0) to be treated daily with estradiol-17ß benzoate (EB; 0, 0.01, 0.1, 1, or 10 µg/kg body weight·d) during one of two developmental periods (PND 14–27 or 42–55). All ewes were hemiovariohysterectomized at the end of EB treatment on either PND 28 or 56, and the remaining uterine horn and ovary removed on PND 112. Immediate responses to EB treatment included dose- and age-dependent increases in uterine wet weight, thickness of the endometrium, myometrium, and LE, but decreases in endometrial glands on PND 28 and 56. Transient exposure to EB decreased gland number and thickness of the endometrium and LE on PND 112 but did not affect extrauterine reproductive tract structures. The mechanism of estrogen inhibition of uterine development did not involve effects on cell proliferation. Real-time PCR analyses found that EB exposure disrupted normal patterns of growth factor (IGF-I, IGF-II, fibroblast growth factor-7, fibroblast growth factor-10, and hepatocyte growth factor) and receptor mRNA expression in the uterus. Transient exposure of the neonatal ewe to estrogens during critical periods specifically alters growth factor networks that perturb normal development of the uterus, leading to permanent alterations in uterine structure and function.

This article has been cited by other articles:

				K. Hayashi, A. R O'Connell, J. L Juengel, K. P McNatty, G. H Davis, F. W Bazer, and T. E Spencer Postnatal uterine development in Inverdale ewe lambs Reproduction, March 1, 2008; 135(3): 357 - 365. [Abstract] [Full Text] [PDF]

				K. Hayashi, R. C. Burghardt, F. W. Bazer, and T. E. Spencer WNTs in the Ovine Uterus: Potential Regulation of Periimplantation Ovine Conceptus Development Endocrinology, July 1, 2007; 148(7): 3496 - 3506. [Abstract] [Full Text] [PDF]

				K. Hayashi and T. E. Spencer WNT Pathways in the Neonatal Ovine Uterus: Potential Specification of Endometrial Gland Morphogenesis by SFRP2 Biol Reprod, April 1, 2006; 74(4): 721 - 733. [Abstract] [Full Text] [PDF]

				K. Hayashi and T. E. Spencer Estrogen Disruption of Neonatal Ovine Uterine Development: Effects on Gene Expression Assessed by Suppression Subtraction Hybridization Biol Reprod, October 1, 2005; 73(4): 752 - 760. [Abstract] [Full Text] [PDF]

				K. Hayashi, K. D Carpenter, T. H Welsh Jr, R. C Burghardt, L. J Spicer, and T. E Spencer The IGF system in the neonatal ovine uterus Reproduction, March 1, 2005; 129(3): 337 - 347. [Abstract] [Full Text] [PDF]