Jean-Paul Praud

Thyroid Disruption by Low-Dose BDE-47 in Prenatally Exposed Lambs

The purpose of this study was to evaluate whether polybrominated diphenyl ethers (PBDE) at levels reported for human populations affect the thyroid state in pregnant sheep and lambs. Pregnant sheep were exposed to vehicle or BDE-47 (0.2, 2 and 20 μg/kg b.w.) from the 5th to 15th week of gestation by intravenous injections weekly. Thyroid hormone levels and BDE-47 content in the blood of sheep and lambs and adipose tissue were analyzed. We observed a significant decrease in total T4 and T3 in exposed lambs without any effect in pregnant sheep. Our finding indicates that prenatal low-dose PBDE exposure results in PBDE storage in fat of offspring and can affect thyroid metabolism in the developing fetus.

Ventilatory response to keto-doxapram in intact and carotid body denervated lambs

We aimed to investigate the role of the carotid bodies in the ventilatory response to keto-doxapram, and whether this response was dose-dependent; we studied two group (n = 5 per group) of awake, intact and carotid-body denervated (CBD) lambs, aged 10-15 days. At 20 min intervals, they received 0.5, 1.0, 2.5 and 5.0 m g/kg mg/kg of keto-doxapram as an intravenous bolus infusion. Plasma keto-doxapram was measured (HPLC). Ventilation was recorded via a face mask and a pneumotachograph. In intact lambs, an immediate dose-dependent increase in minute ventilation (V1) was observed. At 2 min, VI increased from baseline by 125 +/- 28, 212 +/- 49, 378 +/- 41 and 637 +/- 92 mol.kg 1.min 1 (mean +/- SE, P less than 0.01) corresponding to the foregoing incremental doses. A significant correlation was observed between the peak VI and the corresponding plasma keto-doxapram concentrations (r = 0.73, P less than 0.0003). In CBD lambs, VI increased significantly less than in intact animals. In conclusion, early ventilatory response to keto-doxapram depends mainly on intact carotid bodies, and the effect is dose-dependent.