Neuropeptide Y Has a Central Inhibitory Action on the Hypothalamic-Pituitary-Thyroid Axis1

Csaba Fekete, Joseph Kelly, Emese Mihály, Sumit Sarkar, William M. Rand, Gábor Légrádi, Charles H. Emerson, Ronald M. Lechan
2001 Endocrinology  
Recent evidence suggests that neuropeptide Y (NPY), originating in neurons in the hypothalamic arcuate nucleus, is an important mediator of the effects of leptin on the central nervous system. As these NPY neurons innervate hypophysiotropic neurons in the hypothalamic paraventricular nucleus (PVN) that produce the tripeptide, TRH, we raised the possibility that NPY may be responsible for resetting of the hypothalamic-pituitary-thyroid (HPT) axis during fasting. To test this hypothesis, the
more » ... ts of intracerebroventricularly administered NPY on circulating thyroid hormone levels and proTRH messenger RNA in the PVN were studied by RIA and in situ hybridization histochemistry, respectively. NPY administration suppressed circulating levels of thyroid hormone (T 3 and T 4 ) and resulted in an inappropriately normal or low TSH. These alterations were associated with a significant suppression of proTRH messenger RNA in the PVN, indicating that NPY infusion had resulted in a state of central hypothyroidism. Similar observations were made in NPYinfused animals pair fed to the vehicle-treated controls. These data are reminiscent of the effect of fasting on the thyroid axis and indicate that NPY may play a major role in the inhibition of HPT axis during fasting. (Endocrinology
doi:10.1210/endo.142.6.8207 pmid:11356711 fatcat:lv6xgtzspnhdpcw2xxd26ft2z4