Acute and chronic leptin effect upon in vivo and in vitro rat thyroid iodide uptake.

Leptin has stimulatory effects on the hypothalamic-pituitary-thyroid axis and on deiodinases activities. Here, we evaluated the effect of leptin injection upon in vivo and in vitro thyroid 125I uptake (RAIU). We designed two experiments: acute leptin (LepA) with a single dose of leptin (8 microg/100 g BW/sc), and chronic leptin (LepC), injected with the same dose of LepA, once a day, for 6 days.

Estrogen modulates neuromedin B effects on thyrotropin and prolactin release in vitro.

Neuromedin B(NB), a bombesin-like peptide, has been shown to inhibit thyrotropin (TSH) release in pituitary explants of male rats and to stimulate Prolactin (PRL) release in male pituitary cell cultures. We investigated the effect of estrogen status of female rats on the response of thyrotrophs and lactotrophs to neuromedin B (NB) in vitro. Ovariectomized rats were treated with near-physiological or high doses of 17beta estradiol benzoate (0.