title: Alteration of pregnancy related hormones and fetal survival in F-344 rats exposed by inhalation to benzo(a)pyrene.
abstract: The objective of this study was to evaluate the effect of subacute exposure to inhaled benzo(a)pyrene (BaP) on fetal survival and luteal maintenance using timed-pregnant Fisher 344 rats. Prior to assignment of pregnant rats to treatment and control groups, numbers of implantation sites were determined on gestation day (GD) 8 via midventral laparotomy. Subsequently, animals were assigned randomly to three treatment groups and two control groups. Treatment consisted of subacute exposure of rats via inhalation to BaP 25, 75, and 100 micro g/m(3), 4h daily for 10 days (GD-11-20). Control animals were either sham exposed to carbon black (CB) to control for inert BaP carrier or remained unexposed (UNC). Blood samples were collected on days 15 and 17 of gestation via sinus orbital veini-puncture for plasma. Number of pups per litter was determined postpartum and fetal survival rate was expressed as a percentage of the corresponding implantation sites. Radioimmunoassays were used to determine plasma progesterone, estrogen, and prolactin (indirect measurement of decidual luteotropin) concentrations. Fetal survival among BaP-treated rats declined in a dose-dependent manner (25 micro g/m(3), 78.3% per litter; 75 micro g/m(3), 38.0% per litter; 100 micro g/m(3), 33.8% per litter; P<0.05) compared with CB (96.7% per litter) and UNC (98.9% per litter). Plasma progesterone, estrogen, and prolactin concentrations also declined as a result of subacute exposure of rats to BaP compared to controls. These data suggest that inhaled BaP compromised fetal survival and consequently luteotropic activity in the exposed animals.
authors.affiliation: Department of Obstetrics/Gynecology, Reproductive Sciences Laboratory, Meharry Medical College, 1005 D B Todd Boulevard, Nashville, TN 37208, USA. aarchibong@mmc.edu
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Archibong
authors.forename: Frank
authors.initials: F
authors.lastname: Inyang
authors.forename: Aramandla
authors.initials: A
authors.lastname: Ramesh
authors.forename: Michael
authors.initials: M
authors.lastname: Greenwood
authors.forename: Tultul
authors.initials: T
authors.lastname: Nayyar
authors.forename: Prapaporn
authors.initials: P
authors.lastname: Kopsombut
authors.forename: Darryl B
authors.initials: DB
authors.lastname: Hood
authors.forename: Alfred M
authors.initials: AM
authors.lastname: Nyanda
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D001564:Benzo(a)pyrene / Q000008:administration & dosage / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D010064:Embryo Implantation / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects; D004967:Estrogens / Q000097:blood; D005260:Female; D005313:Fetal Death / Q000139:chemically induced*; D008098:Litter Size / Q000187:drug effects; D018811:Maternal Exposure; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011388:Prolactin / Q000097:blood; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D004967:Estrogens; D001564:Benzo(a)pyrene; D011374:Progesterone; D011388:Prolactin