title: Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on secretion of steroids and STAR, HSD3B and CYP19A1 mRNA expression in chicken ovarian follicles.
abstract: The aim of the study was to investigate the in vitro effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on steroid hormone secretion by chicken ovarian follicles and mRNA expression of genes involved in steroids synthesis. In the first in vitro experiment, white (WF) and yellowish (YF) follicles and fragments of the theca (TL) and granulosa (GL) layers of the 3 largest yellow preovulatory follicles (F3-F1) were incubated in a medium supplemented with TCDD (0.01-100nM). In the second experiment, they were incubated in a medium with TCDD (10nM), ovine LH (10ng/mL; oLH) or a combination of oLH (10ng/mL) and TCDD (10nM). It was found that TCDD decreased estradiol (E2) secretion by WF and the TL of all preovulatory follicles, testosterone (T) secretion by WF, YF, and the TL of F2 and F1 follicles, and progesterone (P4) secretion by the GL of the preovulatory follicles. It also reduced oLH-stimulated E2 and P4 secretion by all examined follicles and T by WF. Real-time qPCR revealed that TCDD affected basal and oLH-stimulated expression of STAR, HSD3B and CYP19A1 mRNAs in all investigated ovarian follicles. In conclusion, the data obtained indicate that TCDD inhibits sex steroids secretion from chicken ovarian follicles. The effects of TCDD depend on its concentration and the stage of follicle maturation, and are associated with modulation of STAR, HSD3B and CYP19A1 mRNAs expression. These results indicate that the exposure of the laying hen to TCDD by influence of ovarian steroidogenesis may impair the selection of white follicles to preovulatory hierarchy and disturb their growth and preovulatory maturation.
authors.affiliation: Department of Animal Physiology and Endocrinology, University of Agriculture in Krakow, Al. Mickiewicza 24/28, 30-059 Krakow, Poland. Electronic address: rzsechma@cyf-kr.edu.pl.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Sechman
authors.affiliation: Department of Animal Physiology and Endocrinology, University of Agriculture in Krakow, Al. Mickiewicza 24/28, 30-059 Krakow, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Antos
authors.affiliation: Department of Animal Physiology and Endocrinology, University of Agriculture in Krakow, Al. Mickiewicza 24/28, 30-059 Krakow, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Katarzyńska
authors.affiliation: Department of Animal Physiology and Endocrinology, University of Agriculture in Krakow, Al. Mickiewicza 24/28, 30-059 Krakow, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Grzegorzewska
authors.affiliation: Department of Animal Reproduction and Anatomy, University of Agriculture in Krakow, Al. Mickiewicza 24/28, 30-059 Krakow, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Wojtysiak
authors.affiliation: Department of Animal Physiology and Endocrinology, University of Agriculture in Krakow, Al. Mickiewicza 24/28, 30-059 Krakow, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Hrabia
mesh_terms: D000818:Animals; D001141:Aromatase / Q000235:genetics / Q000378:metabolism; D002645:Chickens; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D006080:Ovarian Follicle / Q000187:drug effects* / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D011374:Progesterone / Q000378:metabolism*; D011375:Progesterone Reductase / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D026901:Membrane Transport Proteins; D010750:Phosphoproteins; D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D000098682:Steroidogenic Acute Regulatory Protein; D011374:Progesterone; D004958:Estradiol; D011375:Progesterone Reductase; D001141:Aromatase
keywords: Chicken; Ovary; Steroidogenesis; TCDD