title: Patterns of hypothalamic GnIH change over the reproductive period in starlings and rats.
abstract: Gonadotropin inhibitory hormone (GnIH) exerts powerful inhibitory effects on various levels of the vertebrate hypothalamic-pituitary-gonadal (reproductive) axis, yet little is known of how it might change naturally over the course of reproduction. We characterized patterns of hypothalamic GnIH cell abundance over the reproductive period in two popular models used for the study of reproductive endocrinology: European starlings (Sturnus vulgaris) and Sprague-Dawley rats (Rattus norvegicus). We also examined the effects on an unpredictable change in the environment on GnIH cell abundance during the reproductive period, specifically during the period of parental care, by simulating a nest predation event and removing eggs/pups. In both species, we report changes in GnIH cell abundance are occurring at similar reproductive time points but are not always directionally parallel; this may be due to a difference in life histories and physiology mediating parental care. We discovered that cells immunoreactive for the GnIH peptide in male and female starlings are most highly abundant on the first day of incubation and the first day after the first chick hatches. Conversely in rats, GnIH cell abundance decreases in dams on the first day after pups are born. In both male and female starlings and female rats, GnIH cell abundance increases in response to egg/pup loss, indicating that GnIH responds to an unpredictable change in the environment in a potentially conserved fashion. These changes in GnIH cell abundance during the reproductive period inspire further investigation of its adaptive role in reproductive physiological events and behaviors, especially parental care.
authors: Department of Neurobiology, Physiology, and Behavior, University of California, Davis, CA, USA; Department of Integrative Biology, University of California, Berkeley, CA, USA. Electronic address: rmcalisi@ucdavis.edu.
authors: R M
authors: RM
authors: Calisi
authors: Department of Integrative Biology, University of California, Berkeley, CA, USA.
authors: A C
authors: AC
authors: Geraghty
authors: Department of Integrative Biology, University of California, Berkeley, CA, USA.
authors: A
authors: A
authors: Avila
authors: Department of Integrative Biology, University of California, Berkeley, CA, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA.
authors: D
authors: D
authors: Kaufer
authors: Department of Integrative Biology, University of California, Berkeley, CA, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA.
authors: G E
authors: GE
authors: Bentley
authors: Department of Neurobiology, Physiology, and Behavior, University of California, Davis, CA, USA.
authors: J C
authors: JC
authors: Wingfield
mesh_terms: D000818:Animals; D005260:Female; D006062:Gonadotropins / Q000378:metabolism*; D007028:Hypothalamic Hormones / Q000378:metabolism*; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism*; D008297:Male; D010455:Peptides / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D012098:Reproduction / Q000502:physiology*; D046749:Starlings / Q000378:metabolism*
chemical_list: D006062:Gonadotropins; D007028:Hypothalamic Hormones; D010455:Peptides
keywords: Gonadotropin; Parental care; RFRP; RFamide-related peptide; Reproduction