title: Prior experience with photostimulation enhances photo-induced reproductive response in female house finches.
abstract: In vertebrates, reproductive output often increases with age. Unlike older birds, first-year photoperiodic birds lack experience with the reproductively stimulatory effects of long day lengths (photostimulation). We examined whether age-related differences in annual reproductive development could be partially attributed to previous experience with photostimulation in the photoperiodic house finch (Carpodacus mexicanus). By manipulating photoperiod, we generated 2 groups of first-year females: a photo-experienced group that underwent 1 photoperiodically induced cycle of gonadal development and regression and a photo-naïve group exposed to long days since hatch. We transferred both groups from long to short days and then photostimulated and exposed them to male birdsong prior to sacrifice. Following concurrent photostimulation, both groups exhibited similar plasma luteinizing hormone surges and hypothalamic vasoactive intestinal polypeptide immunoreactivity. In contrast, hypothalamic gonadotropin-releasing hormone immunoreactivity and circulating vitellogenin levels were higher in photo-experienced birds, and yolk deposition occurred in only 2 females, both of which were photo-experienced. Our results demonstrate that photo-experience enhances some aspects of early photo-induced reproductive development and raise the hypothesis that photo-experience may account for at least some age-related variation in reproductive output.
authors: Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA. kgsalvan@sfu.ca
authors: Katrina G
authors: KG
authors: Salvante
authors: Alistair
authors: A
authors: Dawson
authors: Robert A
authors: RA
authors: Aldredge
authors: Peter J
authors: PJ
authors: Sharp
authors: Keith W
authors: KW
authors: Sockman
mesh_terms: D000818:Animals; D015992:Body Mass Index; D005260:Female; D046369:Finches / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D007031:Hypothalamus / Q000502:physiology; D008027:Light; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D017440:Photoperiod; D012098:Reproduction / Q000502:physiology*; D063346:Singing; D014819:Vitellogenins / Q000378:metabolism
chemical_list: D014819:Vitellogenins; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone