title: Estrogen down-regulates mRNA encoding the exocytotic protein SNAP-25 in the rat pituitary gland.
abstract: Exocytosis is dependent on specific proteins that are located at the secretory granule membrane, in the cytoplasm or at the plasma membrane. The mRNA expression of synaptosomal-associated protein of 25 kDa (SNAP-25) isoforms SNAP-25a and SNAP-25b, vesicle associated membrane protein (VAMP) 2, mammalian homologue of unc-18 (munc-18) and Hrs-2 was studied in the pituitary of ovariectomized rats after subcutaneous insertion of capsules containing estrogen or placebo using in situ hybridization. Estrogen treatment (0.25 mg estradiol) significantly decreased SNAP-25a (32%; 10%) and SNAP-25b (25%; 22%) mRNA levels in the anterior and intermediate lobes, respectively, whereas VAMP-2, munc-18 and Hrs-2 mRNA levels remained unchanged. The results suggest that estrogen selectively regulates SNAP-25 transcription in the pituitary gland, but leaves VAMP-2, munc-18 and Hrs-2 mRNA levels unaffected.
authors.affiliation: Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Jacobsson
authors.forename: H
authors.initials: H
authors.lastname: Razani
authors.forename: S O
authors.initials: SO
authors.lastname: Ogren
authors.forename: B
authors.initials: B
authors.lastname: Meister
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics; D000818:Animals; D004343:Drug Implants; D056827:Endosomal Sorting Complexes Required for Transport; D004958:Estradiol / Q000494:pharmacology*; D005089:Exocytosis / Q000502:physiology*; D005260:Female; D017403:In Situ Hybridization; D008565:Membrane Proteins / Q000235:genetics; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000502:physiology; D010052:Ovariectomy; D010750:Phosphoproteins; D010902:Pituitary Gland / Q000378:metabolism*; D050683:R-SNARE Proteins; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins
chemical_list: D004343:Drug Implants; D056827:Endosomal Sorting Complexes Required for Transport; D008565:Membrane Proteins; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D050683:R-SNARE Proteins; D012333:RNA, Messenger; C494210:Snap25 protein, rat; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins; D004958:Estradiol; D000251:Adenosine Triphosphatases; C115505:Hgs protein, rat