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Regulation of Thyrotropin Releasing Hormone Degrading Enzymes in Rat Brain and Pituitary by L‐ 3,5,3′‐Triiodothyronine
Author(s) -
Suen ChenShian,
Wilk Sherwin
Publication year - 1989
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1989.tb02537.x
Subject(s) - medicine , endocrinology , triiodothyronine , thyrotropin releasing hormone , hormone , anterior pituitary , hypothalamus , neurotensin , chemistry , neuropeptide , biology , receptor
The effect of treatment with L‐3,5,3′‐triiodothyro‐nine (T 3 ) on the levels of pyroglutamyl peptidase I and pyroglutamyl peptidase II in rat brain regions, pituitary, and serum was studied. Pyroglutamyl peptidase I cleaves pyroglutamyl peptides such as thyrotropin releasing hormone (TRH), luteinizing hormone releasing hormone, neurotensin, and bombesin, whereas pyroglutamyl peptidase II appears to be specific for TRH. Acute administration of T 3 did not affect pyroglutamyl peptidase I in any of the regions studied, whereas pyroglutamyl peptidase II was significantly elevated in frontal cortex and pituitary. Treatment with T 3 for 10 or 14 days significantly elevated pyroglutamyl peptidase I in pituitary, hypothalamus, olfactory bulb, hippocampus, and thalamus. Chronic T 3 treatment elevated pyroglutamyl peptidase II in frontal cortex and in serum. These studies demonstrate regulation of neuropeptide degrading enzymes by thyroid hormones in vivo. This regulation may play a role in the negative feedback control of thyroid status by T 3 .