biostudies-literatureRodriguez-Rodriguez AConsejo Nacional de Humanidades, Ciencias y Tecnologías725https://www.ebi.ac.uk/biostudies/studies/S-EPMC12110239biostudies-literatureUnknown14(10)The amplitude of the phasic output of thyrotropin-releasing hormone (TRH) into the hypothalamus-pituitary portal capillaries is likely controlled by the TRH-degrading ectoenzyme (TRH-DE) expressed on the surface of median eminence (ME) β2-tanycytes. To extend this hypothesis, we performed experiments on adult rodents reared in standard conditions. TRH-DE was close to the putative sites of TRH release in the male rat external layer of the ME. In global <i>Trhde</i> knockout mice, basal hypothalamus-pituitary-thyroid (HPT) axis parameters were not altered but we detected an increased vimentin (a tanycyte marker) positive coverage of the portal vessels. We then overexpressed TRH-DE or a dominant negative isoform by microinjection of adeno-associated virus 1 (AAV1) vectors into the third ventrCellsHypothalamic Median Eminence Thyrotropin-Releasing Hormone-Degrading Ectoenzyme Activity Is Dispensable for Basal Thyroid Axis Activity in Lean Rodents.PMC121102392015-01-562CBF2023-2024-7322014-254960Cote-Velez AJoseph-Bravo PCharli JLUribe RMRodriguez-Rodriguez AfalseHypothalamic Median Eminence Thyrotropin-Releasing Hormone-Degrading Ectoenzyme Activity Is Dispensable for Basal Thyroid Axis Activity in Lean Rodents.The amplitude of the phasic output of thyrotropin-releasing hormone (TRH) into the hypothalamus-pituitary portal capillaries is likely controlled by the TRH-degrading ectoenzyme (TRH-DE) expressed on the surface of median eminence (ME) β2-tanycytes. To extend this hypothesis, we performed experiments on adult rodents reared in standard conditions. TRH-DE was close to the putative sites of TRH release in the male rat external layer of the ME. In global <i>Trhde</i> knockout mice, basal hypothalamus-pituitary-thyroid (HPT) axis parameters were not altered but we detected an increased vimentin (a tanycyte marker) positive coverage of the portal vessels. We then overexpressed TRH-DE or a dominant negative isoform by microinjection of adeno-associated virus 1 (AAV1) vectors into the third ventr2025-01-01T00:00:00Z2025 May2026-05-23T03:14:05.174Z2026-05-23T03:08:24.827ZS-EPMC121102394042222810.3390/cells14100725