peptide and protein hormone signaling pathway thyroid-stimulating hormone signaling pathway 2013-03-26T10:29:31Z PW:0001200 TSH signaling pathway Thyroid-stimulating hormone (TSH) signaling stimulates the secretion of thyroid hormone. Its own secretion is dependent upon activation of thyrotropin-releasing hormone (TRH) in the hypothalamus by low levels of thyroid hormone (TH). TRH, TSH and TH signaling pathways are part of the hypothalamic-pituitary-thyroid (HPT) axis for which TH itself provides a negative regulatory loop. pathway thyrotropin signaling pathway vpetri