Adrenal gland SNAP-25 expression is altered in thyroid hormone receptor knockout mice

SNAP-25 is a protein in neurons and neuroendocrine cells, which is involved , together with syntaxin and VAMP, in neurotransmitter release and neurite outgrowth. Since the thyroid hormone receptors TR alpha and TR beta are ess ential for nervous system development, their possible role in regulating th e expression of these vesicle trafficking proteins was examined by analysin g SNAP-25 levels in TR alpha and TR beta knockout mice. Immunoblotting and RT-PCR showed that SNAP-25 levels are increased in the adrenal gland, but n ot in cerebellum, in knock-out mice,while syntaxin-1 and VAMP-2 are unaffec ted in either tissue. Treatment of the pheochromocytoma-derived cell line P C12 with the thyroid hormone L-3,5,3'-triiodothyronine (T3) decreased SNAP- 25 expression; Together, these data suggest that thyroid hormones exert a n egative regulatory effect on SNAP-25 in adrenal medullary neuroendocrine ce lls. NeuroReport 12:1427-1430 (C) 2001 Lippincott Williams & Wilkins.