Uribe RM, Joseph-Bravo P, Ponce G, Cisneros M, Aceves C, Charli JL. Influence of thyroid status on TRH metabolism in rat olfactory bulb.
Peptides 1994;
15:435-9. [PMID:
7937315 DOI:
10.1016/0196-9781(94)90201-1]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effect of thyroid hormones (TH) on the metabolism of thyrotropin-releasing hormone (TRH) in the olfactory bulb (OB) was compared with the hypothalamic response to TRH. Two methods were used to induce hypothyroidism: propylthiouracyl-methimazole (PTU-M) or 131I treatment. Hyperthyroidism was produced by 3,3',5-triiodo-L-thyronine (T3) injections to the hypothyroid animals. With PTU-M treatment, paraventricular TRH mRNA levels increased 57% and returned to the euthyroid level with T3 treatment. In OB, TRH mRNA was not altered. The TRH content was unaffected in the mediobasal hypothalamus of PTU-M-treated animals whereas it was reduced in OB (31%) with no further response upon T3 treatment. 131I-induced hypothyroidism did not modify the OB TRH content but it was decreased (31%) in hyperthyroids. In the median eminence, TRH increased 26% in hypothyroids, and the response was reversed with T3. Our results demonstrate that treatments that change thyroid status can alter TRH levels in the OB, probably at a translational or postranslational level, though the effects may be pharmacological.
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