title: Immunocytochemical studies of tryptophan hydroxylase, tyrosine hydroxylase, and serotonin innervation in the aging rat neurointermediate pituitary.
abstract: Innervation within the aging male rat pituitary neurointermediate lobe was examined using immunocytochemical methods with antisera to rate-limiting enzymes for serotonin (tryptophan hydroxylase, TpOH) or catecholamine (tyrosine hydroxylase TH) synthesis. Immunostaining for both enzymes was observed in both neural and intermediate lobes in younger rats (age 6 weeks or 7 months), but TpOH was absent from the intermediate lobe in older groups (10-12, 15-16, and 18-19 months). Colocalization of TpOH and TH was demonstrated in some nerve fibers, using immunofluorescence. The oldest age group showed a reduced staining pattern for TH. 5-hydroxytryptophan, the immediate precursor for serotonin (5-HT), was taken up and converted to immunoreactive 5-HT in all age groups. Overall, the pattern of staining for regulatory neurotransmitters or enzymes which ultimately affect pituitary intermediate lobe secretory function is significantly modulated during the aging process.
authors.affiliation: Department of Anatomy, University of New Mexico School of Medicine, Albuquerque 87131-5211.
authors.forename: L C
authors.initials: LC
authors.lastname: Saland
authors.forename: A
authors.initials: A
authors.lastname: Samora
authors.forename: P
authors.initials: P
authors.lastname: Sanchez
authors.forename: G
authors.initials: G
authors.lastname: Chavez
mesh_terms: D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000375:Aging / Q000378:metabolism*; D000818:Animals; D007150:Immunohistochemistry; D008297:Male; D010902:Pituitary Gland / Q000737:chemistry* / Q000201:enzymology / Q000294:innervation; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000032:analysis*; D014365:Tryptophan Hydroxylase / Q000032:analysis* / Q000276:immunology; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis*
chemical_list: D012701:Serotonin; D006916:5-Hydroxytryptophan; D014446:Tyrosine 3-Monooxygenase; D014365:Tryptophan Hydroxylase