title: Multiple co-localizations in arcuate GHRH-eGFP neurons in the mouse hypothalamus.
abstract: In the present work, we took advantage of a recently described model of GHRH-enhanced green fluorescent protein (eGFP) transgenic mice to evaluate the extent of co-localization of GHRH neurons with galanin (GAL), neurotensin (NT) and tyrosine hydroxylase (TH) in 3- and 8-month-old male and female mice. The total number of GHRH-eGFP neurons along the rostro-caudal axis of the arcuate nucleus did not differ according to gender or age. GAL-immunoreactivity was present in 40-44% of 3-month-old GHRH-eGFP neurons in male and female arcuate nucleus, respectively, but only 25-22% in 8-month-old mice. TH immunoreactivity occurred in 36-35% of GHRH-eGFP neurons in male and female arcuate nucleus from 3-month-old mice and these proportions increased to 40 and 45% in 8-month-old mice. NT immunoreactivity was present in 14 and 24% of GHRH-eGFP neurons in male and female arcuate nucleus from 3-month-old mice up to 28 and 26% in 8-month-old mice. Thus, co-localization of peptides and enzyme in GHRH-eGFP neurons displays a sexual dimorphism at 3-month of age for NT, and at 8-month for TH, while the total number of GHRH-eGFP neurons does not exhibit gender difference at either age. In summary, it appears that changes in co-localized (and presumably co-released) peptides, rather than GHRH per se, may contribute to the changes in sexually dimorphic GH secretion with aging in the mouse.
authors.affiliation: UMR 549 INSERM, Faculté de Médecine, Université Paris-René Descartes, IFR Broca Sainte Anne, 2ter rue d'Alésia, 75014 Paris, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Bouyer
authors.forename: Catherine
authors.initials: C
authors.lastname: Loudes
authors.forename: Iain C A F
authors.initials: IC
authors.lastname: Robinson
authors.forename: Jacques
authors.initials: J
authors.lastname: Epelbaum
authors.forename: Annie
authors.initials: A
authors.lastname: Faivre-Bauman
mesh_terms: D000375:Aging; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism*; D001931:Brain Mapping / Q000379:methods; D005260:Female; D019004:Galanin / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D013007:Growth Hormone-Releasing Hormone / Q000378:metabolism*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000378:metabolism*; D009496:Neurotensin / Q000378:metabolism*; D012737:Sex Factors; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D049452:Green Fluorescent Proteins; D009496:Neurotensin; D019004:Galanin; D013007:Growth Hormone-Releasing Hormone; D014446:Tyrosine 3-Monooxygenase