Hypothalamic Median Eminence Thyrotropin-Releasing Hormone-Degrading Ectoenzyme Activity Is Dispensable for Basal Thyroid Axis Activity in Lean Rodents.

ABSTRACT: 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 Trhde 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 ventr

SUBMITTER: Rodriguez-Rodriguez A 

PROVIDER: S-EPMC12110239 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature