Secretion of human chorionic gonadotropin in superfused young placental tissue exposed to cadmium

Abstract

The effect of various concentrations of cadmium (Cd) in levels ranging from 0.75 to 12 micrograms/ml medium, on the secretion of human chorionic gonadotropin (hCG) in first-trimester placental explants, after 6 or 24 h incubation, employing both static and dynamic systems was examined. Later the unbound Cd was washed for 45 min with fresh medium devoid of Cd, followed by superfusion with the latter medium for 75 min, during which time samples were collected for hCG assay. For the superfusion experiments the parameters used for evaluating the hCG secretion pattern were: mean peak amplitude (MPA), pulse frequency (PF) and the area under the hCG secretion curve (AUC). The results indicate that in the dynamic system the hCG secretion increased significantly, and this increase was dose dependent. There was also a dose-related increase in mean total hCG secreted by the explants exposed to Cd. Maximal hCG secretion was observed after 24 h exposure of explants to 6 micrograms of the metal/ml. Both the MPA and AUC parameters showed a statistically significant increase for this dose level. At 12 micrograms/ml, the pulsatile secretion of hCG decreased, the value for the mean hCG secretion being comparable to that observed for 0.75 micrograms/ml. After 6 h incubation, however, there were no significant changes from the control, as judged by all of the above parameters. The levels of hCG secreted by the explants into the media in the static system were not significantly different from their respective controls, for both incubation periods and Cd levels. These results indicate that Cd may affect the normal placental function, as reflected in its hCG secretion pattern.

Metallothionein Overexpression in Human Trophoblastic Cells Protects Against Cadmium-Induced Apoptosis

“…To gain insight into how gestational Cd exposure may lead to altered trophoblast function and subsequent adverse pregnancy outcomes (Weir et al, 1990;Goyer, 1991Goyer, , 1997Boadi et al, 1992a and1992b;Lin et al, 1997), we have examined the involvement of MT, whose expression is potently induced by Cd, particularly in terms of protecting trophoblastic cells from Cd toxicity. Subpopulations of the human trophoblastic cell line, JEG-3, were stably trans-fected with expression constructs containing the full-length hMT-IIa cDNA in either the sense (MT-JEG) or antisense (aMT-JEG) orientation.…”

“…Absorbed maternal Cd preferentially accumulates in the placenta, and crosses into the fetus in minimal amounts (Sikorski et al, 1988;Galicia-Garcia et al, 1997). As a result, trophoblast functions, including maternal-fetal transport and hormone production, are disrupted (Weir et al, 1990;Goyer, 1991Goyer, , 1997Boadi et al, 1992aBoadi et al, , 1992bLin et al, 1997).…”

Effet du tabagisme sur l’implantation embryonnaire et la placentation précoce et facteurs influençant la toxicité tabagique sur la reproduction (Partie II)

“…En effet, in vitro, il a é té dé montré que de faibles doses de cadmium ou de BaP induisaient une diminution de la sé cré tion d'HCG par les cellules trophoblastiques du placenta. À l'inverse, de hautes doses de cadmium entraînaient une inhibition des pulses de HCG [44,45]. Ces modifications des profils de sé cré tion de l'HCG en fonction du type et de la dose du toxique sont probablement impliqué es dans les diffé rents degré s d'alté ration de l'implantation et dans la complexité des anomalies de la placentation pré coce lié s à l'exposition au tabagisme.…”

Posterity Development Violations of the Lead Intoxicated Animals

“…С винец и его токсические соедине-ния являются опасными загряз-нителями окружающей среды, оказы-вающими негативное воздействие на репродуктивную функцию женщины, приводя к различным нарушениям в развитии плода [1,2].…”