The orphan nuclear receptor SF-1 is involved in the effect of PCBs, DDT, and DDE on the secretion of steroid hormones and oxytocin from bovine luteal cells during the estrous cycle in vitro

Effects of DDT, DDE, aldrin and dieldrin on prostaglandin, oxytocin and steroid hormone release from smooth chorion explants of cattle

Chlorooganic xenobiotics (XBs) such as DDT, DDE, aldrin and dieldrin interfere with release of hormones from chorionic villi that are necessary for sustaining the normal course pregnancy: prostaglandins (PGs), oxytocin (OT), progesterone (P₄) and estradiol (E₂). Approximately 20 %-40 % of these hormones originate from the smooth chorion. The aim of current studies was to investigate effects of these XBs on synthesis and release of PGE₂, PGF_2α, OT, P₄ and E₂ from explants of smooth chorion of cattle, obtained during the120-150 and 151-180 day gestational period. Explants were incubated with DDT, DDE, aldrin or dieldrin at concentrations of 1 and 10 ng/mL for 24 h, and concentrations of PGE₂, PGF_2α, OT, P₄ and E₂ in post incubation medium and the relative abundances of COX-2, PTGES, AKR1B1, NP-I/OT, PAM, HSD3B, and CYP19A1 mRNA transcripts in tissue explants were determined. The XBs did not have effects on cell viability in explants (P > 0.05), however, there were effects on prostaglandins, OT and P₄ secretion and relative abundance of mRNA transcript for genes encoding the main enzymes involved in synthesis of these hormones (P < 0.05). The XBs that were evaluated did not have effects on E₂ synthesis and secretion (P > 0.05). In summary, XBs evaluated in the present study had effects on the pattern of prostaglandin secretion, and can increase OT and P₄ release from smooth chorion explants. Because XBs inhibit hormonal action throughout the chorion, there is an increase in risk of abortions or premature births in animals.

Do chlorinated insecticides (aldrin and DDT) or products of their transformations (dieldrin and DDE) impair signal transfer from regulators (oxytocin and relaxin) of bovine myometrium motility in vitro?

Aldrin, dieldrin, and DDT are chlorinated insecticides that are unintentionally widespread in the environment. It was previously shown that all of the aforementioned compounds increased secretion of ovarian oxytocin (OT), which is a potent uterotonic agent. However, only DDT and its metabolite (DDE) promoted, while aldrin and dieldrin inhibited basal and OT-stimulated myometrial contractions in cows. Therefore, the aim of this study was to determine the effect of these treatments on the reception and further transmission of the OT-signal for myometrial contractions and on the levels of contractile-associated integral proteins (caveolin; CAV) and gap junction proteins (GAPs). Moreover, their effect on reception of signal for the relaxation of myometrium was also studied. Myometrial strips or cells from non-pregnant (8-12 days of oestrous cycle) or late pregnant (5-8 months) cows were incubated with the studied compounds at environmentally relevant dose (10 ng/ml), which was chosen according to the previous studies. DDT and DDE increased the CAV protein level, while dieldrin decreased the GAPs level. None of the studied compounds affected mRNA expression of the OT receptor and expression of the second messengers (DAG, IP3, PKC, MLCK). Oppositely, DDE and dieldrin decreased mRNA expression of the relaxin (RLX) receptor. Changes in the amount of contractile-associated integral proteins may be involved in the molecular mechanism underlying the adverse effects of the studied insecticides on myometrial motility. Admittedly, none of the studied compounds impaired the reception or further intracellular transmission of the OT signal to promote contractions during the oestrous cycle, while they showed potential to impair the transmission the signal between cells as well as to diminish the effects of one of the primary inhibitor (RLX) of myometrial contractions during gestation.

Intracellular toxicity exerted by PCBs and role of VBNC bacterial strains in biodegradation

Polychlorinated biphenyls (PCBs) are xenobiotic compounds that persists in the environment for long-term, though its productivity is banned. Abatement of the pollutants have become laborious due to it's recalcitrant nature in the environment leading to toxic effects in humans and other living beings. Biphenyl degrading bacteria co-metabolically degrade low chlorinated PCBs using the active metabolic pathway. bph operon possess different genetic arrangements in gram positive and gram negative bacteria. The binding ability of the genes and the active sites were determined by PCB docking studies. The active site of bphA gene with conserved amino acid residues determines the substrate specificity and biodegradability. Accumulation of toxic intermediates alters cellular behaviour, biomass production and downturn the metabolic activity. Several bacteria in the environment attain unculturable state which is viable and metabolically active but not cultivable (VBNC). Resuscitation-promoting factor (Rpf) and Rpf homologous protein retrieve the culturability of the so far uncultured bacteria. Recovery of this adaptive mechanism against various physical and chemical stressors make a headway in understanding the functionality of both environmental and medically important unculturable bacteria. Thus, this paper review about the general aspects of PCBs, cellular toxicity exerted by PCBs, role of unculturable bacterial strains in biodegradation, genes involved and degradation pathways. It is suggested to extrapolate the research findings on extracellular organic matters produced in culture supernatant of VBNC thus transforming VBNC to culturable state.