title: Neuronal responses in the brainstem and hypothalamic nuclei following insulin treatment during the late follicular phase in the ewe.
abstract: The aim of this study was to determine the neuronal responses following insulin administration during the late follicular phase. Intact ewes were given either saline or insulin (5 IU/kg, i.v.) at 35 h after progesterone withdrawal and killed 3 h later. There was a marked increase in the number of Fos-positive noradrenergic neurones in the caudal brainstem of insulin-treated ewes. In the hypothalamic paraventricular nucleus, insulin treatment increased the presence of Fos-positive corticotrophin-releasing hormone neurones (from 2% to 98%) and Fos-positive arginine vasopressin parvocellular neurones (from 2% to 46%). Interestingly, after insulin treatment, despite a general increase in Fos-positive neurones in the arcuate nucleus (ARC), there was a marked reduction (from 47% to 1%) in Fos-positive β-endorphin neurones. Similarly, colocalized Fos and oestradiol receptor (ER) α-positive neurones decreased in the ARC after insulin (from 7% to 3%). Conversely, in the ventromedial nucleus, ERα-positive neurones with Fos increased (from 7% to 22%) alongside a general increase in Fos-positive neurones. Overall, a complex system of neurones in brainstem and hypothalamus is activated following insulin administration during the late follicular phase.
authors.affiliation: Reproduction Research Group, Department of Veterinary Clinical Science, University of Liverpool, Leahurst, Neston, Wirral, CH64 7TE, UK. ghuman_s@yahoo.co.in
authors.forename: S P S
authors.initials: SP
authors.lastname: Ghuman
authors.forename: R
authors.initials: R
authors.lastname: Morris
authors.forename: J
authors.initials: J
authors.lastname: Scherzer
authors.forename: J E
authors.initials: JE
authors.lastname: Routly
authors.forename: A
authors.initials: A
authors.lastname: Mobasheri
authors.forename: R F
authors.initials: RF
authors.lastname: Smith
authors.forename: H
authors.initials: H
authors.lastname: Dobson
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000166:cytology / Q000187:drug effects; D001127:Arginine Vasopressin / Q000032:analysis; D001933:Brain Stem / Q000166:cytology* / Q000187:drug effects; D002452:Cell Count; D003346:Corticotropin-Releasing Hormone / Q000032:analysis; D047628:Estrogen Receptor alpha / Q000032:analysis; D005260:Female; D005498:Follicular Phase; D007031:Hypothalamus / Q000166:cytology* / Q000187:drug effects; D007328:Insulin / Q000494:pharmacology*; D009474:Neurons / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000187:drug effects; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis; D012756:Sheep / Q000502:physiology*; D001615:beta-Endorphin / Q000032:analysis
chemical_list: D047628:Estrogen Receptor alpha; D007328:Insulin; D016760:Proto-Oncogene Proteins c-fos; D001127:Arginine Vasopressin; D001615:beta-Endorphin; D003346:Corticotropin-Releasing Hormone