Neonatal low-protein diet changes deiodinase activities and pituitary TSH response to TRH in adult rats.

Protein malnutrition during neonatal programs for a lower body weight and hyperthyroidism in the adult offspring were analyzed. Liver deiodinase is increased in such animals, contributing to the high serum triiodothyronine (T3) levels. The level of deiodinase activities in other tissues is unknown.

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.

Peptide YY (PYY)3-36 modulates thyrotropin secretion in rats.

Peptide YY (PYY)3-36 is a gut-derived hormone, with a proposed role in central mediation of postprandial satiety signals, as well as in long-term energy balance. In addition, recently, the ability of the hormone to regulate gonadotropin secretion, acting at pituitary and at hypothalamus has been reported. Here, we examined PYY3-36 effects on thyrotropin (TSH) secretion, both in vitro and in vivo.

Thyroid hormones modulate the endocrine and autocrine/paracrine actions of leptin on thyrotropin secretion.

We investigated the influence of hypo- and hyperthyroidism on the ability of leptin to modulate TSH secretion. Two hours after receiving leptin (8 mug leptin/100 g BW; s.c.