title: Cellular and hormonal disruption of fetal testis development in sheep reared on pasture treated with sewage sludge.
abstract: The purpose of this study was to evaluate whether experimental exposure of pregnant sheep to a mixture of environmental chemicals added to pasture as sewage sludge (n = 9 treated animals) exerted effects on fetal testis development or function; application of sewage sludge was undertaken so as to maximize exposure of the ewes to its contents. Control ewes (n = 9) were reared on pasture treated with an equivalent amount of inorganic nitrogenous fertilizer. Treatment had no effect on body weight of ewes, but it reduced body weight by 12-15% in male (n = 12) and female (n = 8) fetuses on gestation day 110. In treated male fetuses (n = 11), testis weight was significantly reduced (32%), as were the numbers of Sertoli cells (34% reduction), Leydig cells (37% reduction), and gonocytes (44% reduction), compared with control fetuses (n = 8). Fetal blood levels of testosterone and inhibin A were also reduced (36% and 38%, respectively) in treated compared with control fetuses, whereas blood levels of luteinizing hormone and follicle-stimulating hormone were unchanged. Based on immunoexpression of anti-Müllerian hormone, cytochrome P450 side chain cleavage enzyme, and Leydig cell cytoplasmic volume, we conclude that the hormone changes in treated male fetuses probably result from the reduction in somatic cell numbers. This reduction could result from fetal growth restriction in male fetuses and/or from the lowered testosterone action; reduced immunoexpression of alpha-smooth muscle actin in peritubular cells and of androgen receptor in testes of treated animals supports the latter possibility. These findings indicate that exposure of the developing male sheep fetus to real-world mixtures of environmental chemicals can result in major attenuation of testicular development and hormonal function, which may have consequences in adulthood.
authors.affiliation: MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Catriona
authors.initials: C
authors.lastname: Paul
authors.forename: Stewart M
authors.initials: SM
authors.lastname: Rhind
authors.forename: Carol E
authors.initials: CE
authors.lastname: Kyle
authors.forename: Hayley
authors.initials: H
authors.lastname: Scott
authors.forename: Chris
authors.initials: C
authors.lastname: McKinnell
authors.forename: Richard M
authors.initials: RM
authors.lastname: Sharpe
mesh_terms: D000818:Animals; D004785:Environmental Pollutants / Q000009:adverse effects*; D005260:Female; D005308:Fertilizers / Q000009:adverse effects*; D047109:Fetal Development / Q000187:drug effects; D005640:Follicle Stimulating Hormone / Q000097:blood; D007265:Inhibins / Q000097:blood; D007985:Leydig Cells / Q000166:cytology / Q000187:drug effects; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D018811:Maternal Exposure; D011247:Pregnancy; D012708:Sertoli Cells / Q000166:cytology / Q000187:drug effects; D012722:Sewage / Q000009:adverse effects*; D012756:Sheep / Q000196:embryology / Q000378:metabolism; D013737:Testis / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D013739:Testosterone / Q000097:blood
chemical_list: D004785:Environmental Pollutants; D005308:Fertilizers; D012722:Sewage; C422362:inhibin A; D013739:Testosterone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone