title: Acute fasting-induced repression of the hypothalamic-pituitary-gonadal axis is reversed by RF-9 administration in the adult male macaque.
abstract: Recently, hypothalamic RFRP-3 (a mammalian ortholog of avian GnIH) signaling has been proposed as an important negative modulator of the reproductive axis. The current study examined whether repression of reproductive hormonal expression during short-term fasting conditions in higher-order primate is influenced by altered RFRP-3 signaling. Eight intact postpubertal male macaques (Macaca mulatta) were administered a single intravenous bolus of RF-9 (n = 4), a potent and putative RFRP-3 receptor antagonist, or vehicle (n = 4) following a 48-h fasting condition. Intermittent blood samples were collected every 30 min during the 4-h post-bolus period, and blood glucose, plasma cortisol, and testosterone concentrations were measured. Relative to fed conditions, fasting reduced glucose and testosterone levels (p < 0.005) and increased cortisol levels (p < 0.05). Relative to baseline, mean testosterone levels were elevated 150 min after RF-9 (p < 0.05) but not vehicle administration. In addition, elevated mean plasma testosterone levels following RF-9 administration were equivalent to levels observed in normal fed monkeys. These results suggest an important role for RFRP-3 signaling in conveying metabolic state information to the reproductive axis in higher primates.
authors.affiliation: Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
authors.forename: A
authors.initials: A
authors.lastname: Batool
authors.affiliation: Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
authors.forename: R
authors.initials: R
authors.lastname: Naz
authors.affiliation: Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
authors.forename: M
authors.initials: M
authors.lastname: Wazir
authors.affiliation: Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
authors.forename: A
authors.initials: A
authors.lastname: Azam
authors.affiliation: Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
authors.forename: R
authors.initials: R
authors.lastname: Ullah
authors.affiliation: Department of Physiology, Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan.
authors.forename: F
authors.initials: F
authors.lastname: Wahab
authors.affiliation: Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
authors.forename: M
authors.initials: M
authors.lastname: Shahab
mesh_terms: D000218:Adamantane / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D061605:Administration, Intravenous; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D004151:Dipeptides / Q000008:administration & dosage* / Q000494:pharmacology*; D005215:Fasting / Q000097:blood / Q000502:physiology*; D005247:Feeding Behavior; D006066:Gonads / Q000187:drug effects / Q000502:physiology*; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism*; D008251:Macaca; D008297:Male; D010455:Peptides / Q000008:administration & dosage* / Q000494:pharmacology*; D013739:Testosterone / Q000097:blood
chemical_list: D001786:Blood Glucose; D004151:Dipeptides; D010455:Peptides; C508361:adamantylcarbonyl-arginyl-phenylalaninamide; D013739:Testosterone; D000218:Adamantane; D006854:Hydrocortisone