Blood-brain leptin transport and appetite and reproductive neuroendocrine responses to intracerebroventricular leptin injection in sheep: Influence of photoperiod

Influence of photoperiod

Clare Lesley Adam, P.A. Findlay, David Warren Miller

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39 Citations (Scopus)

Abstract

Impaired anorectic actions of leptin may be due to intrahypothalamic insensitivity and/or reduced blood-brain transport. The influence of photoperiod on leptin responses and leptin transport from blood into cerebrospinal fluid (CSF) was examined in sheep. Sheep kept on ad libitum food for 15 wk in long days (LD) had higher voluntary food intake and lower GnRH/LH output than in short days (SD). Food intake was decreased approximately 30% after intracerebroventricular (icv) (and not iv) leptin injection, but only in SD. GnRH/LH secretion was decreased after icv ( but not iv) leptin in both photoperiods. Leptin concentrations in CSF were higher in LD than SD but correlated with plasma leptin only in LD. Amounts of leptin entering CSF after iv leptin injection were greater in LD than SD. In a separate experiment, plasma ( but not CSF) leptin was higher in fat than thin sheep in natural summer LD and after 5 wk in SD. CSF leptin correlated with plasma leptin in LD but not SD. CSF leptin after iv leptin injection was higher in thin than fat sheep but only in LD. Endogenous CSF to plasma concentration ratios correlated negatively with plasma concentrations, indicating decreased blood-brain transport with increased leptinemia. Therefore, icv ( and not iv) leptin inhibited appetite only in SD and decreased GnRH/LH output in both photoperiods, and the proportion of circulating leptin entering CSF was higher in LD and thinner animals. Photoperiod apparently modulates intrahypothalamic leptin sensitivity of appetite, but not reproductive, regulatory pathways, whereas photoperiod and leptinemia influence leptin blood-brain transport.

Original languageEnglish
Pages (from-to)4589-4598
Number of pages10
JournalEndocrinology
Volume147
Issue number10
DOIs
Publication statusPublished - Oct 2006

Keywords

  • LUTEINIZING-HORMONE SECRETION
  • CEREBROSPINAL FLUID BARRIER
  • MATURE MALE SHEEP
  • LH-SECRETION
  • FOOD-INTAKE
  • PHODOPUS-SUNGORUS
  • GROWTH-HORMONE
  • CHOROID-PLEXUS
  • PLASMA LEPTIN
  • FEED-INTAKE

Cite this

@article{dd0c7013298a47859e39e490c20dcbfb,
title = "Blood-brain leptin transport and appetite and reproductive neuroendocrine responses to intracerebroventricular leptin injection in sheep: Influence of photoperiod: Influence of photoperiod",
abstract = "Impaired anorectic actions of leptin may be due to intrahypothalamic insensitivity and/or reduced blood-brain transport. The influence of photoperiod on leptin responses and leptin transport from blood into cerebrospinal fluid (CSF) was examined in sheep. Sheep kept on ad libitum food for 15 wk in long days (LD) had higher voluntary food intake and lower GnRH/LH output than in short days (SD). Food intake was decreased approximately 30{\%} after intracerebroventricular (icv) (and not iv) leptin injection, but only in SD. GnRH/LH secretion was decreased after icv ( but not iv) leptin in both photoperiods. Leptin concentrations in CSF were higher in LD than SD but correlated with plasma leptin only in LD. Amounts of leptin entering CSF after iv leptin injection were greater in LD than SD. In a separate experiment, plasma ( but not CSF) leptin was higher in fat than thin sheep in natural summer LD and after 5 wk in SD. CSF leptin correlated with plasma leptin in LD but not SD. CSF leptin after iv leptin injection was higher in thin than fat sheep but only in LD. Endogenous CSF to plasma concentration ratios correlated negatively with plasma concentrations, indicating decreased blood-brain transport with increased leptinemia. Therefore, icv ( and not iv) leptin inhibited appetite only in SD and decreased GnRH/LH output in both photoperiods, and the proportion of circulating leptin entering CSF was higher in LD and thinner animals. Photoperiod apparently modulates intrahypothalamic leptin sensitivity of appetite, but not reproductive, regulatory pathways, whereas photoperiod and leptinemia influence leptin blood-brain transport.",
keywords = "LUTEINIZING-HORMONE SECRETION, CEREBROSPINAL FLUID BARRIER, MATURE MALE SHEEP, LH-SECRETION, FOOD-INTAKE, PHODOPUS-SUNGORUS, GROWTH-HORMONE, CHOROID-PLEXUS, PLASMA LEPTIN, FEED-INTAKE",
author = "Adam, {Clare Lesley} and P.A. Findlay and Miller, {David Warren}",
year = "2006",
month = "10",
doi = "10.1210/en.2006-0576",
language = "English",
volume = "147",
pages = "4589--4598",
journal = "Endocrinology",
issn = "0013-7227",
publisher = "The Endocrine Society",
number = "10",

}

TY - JOUR

T1 - Blood-brain leptin transport and appetite and reproductive neuroendocrine responses to intracerebroventricular leptin injection in sheep: Influence of photoperiod

T2 - Influence of photoperiod

AU - Adam, Clare Lesley

AU - Findlay, P.A.

AU - Miller, David Warren

PY - 2006/10

Y1 - 2006/10

N2 - Impaired anorectic actions of leptin may be due to intrahypothalamic insensitivity and/or reduced blood-brain transport. The influence of photoperiod on leptin responses and leptin transport from blood into cerebrospinal fluid (CSF) was examined in sheep. Sheep kept on ad libitum food for 15 wk in long days (LD) had higher voluntary food intake and lower GnRH/LH output than in short days (SD). Food intake was decreased approximately 30% after intracerebroventricular (icv) (and not iv) leptin injection, but only in SD. GnRH/LH secretion was decreased after icv ( but not iv) leptin in both photoperiods. Leptin concentrations in CSF were higher in LD than SD but correlated with plasma leptin only in LD. Amounts of leptin entering CSF after iv leptin injection were greater in LD than SD. In a separate experiment, plasma ( but not CSF) leptin was higher in fat than thin sheep in natural summer LD and after 5 wk in SD. CSF leptin correlated with plasma leptin in LD but not SD. CSF leptin after iv leptin injection was higher in thin than fat sheep but only in LD. Endogenous CSF to plasma concentration ratios correlated negatively with plasma concentrations, indicating decreased blood-brain transport with increased leptinemia. Therefore, icv ( and not iv) leptin inhibited appetite only in SD and decreased GnRH/LH output in both photoperiods, and the proportion of circulating leptin entering CSF was higher in LD and thinner animals. Photoperiod apparently modulates intrahypothalamic leptin sensitivity of appetite, but not reproductive, regulatory pathways, whereas photoperiod and leptinemia influence leptin blood-brain transport.

AB - Impaired anorectic actions of leptin may be due to intrahypothalamic insensitivity and/or reduced blood-brain transport. The influence of photoperiod on leptin responses and leptin transport from blood into cerebrospinal fluid (CSF) was examined in sheep. Sheep kept on ad libitum food for 15 wk in long days (LD) had higher voluntary food intake and lower GnRH/LH output than in short days (SD). Food intake was decreased approximately 30% after intracerebroventricular (icv) (and not iv) leptin injection, but only in SD. GnRH/LH secretion was decreased after icv ( but not iv) leptin in both photoperiods. Leptin concentrations in CSF were higher in LD than SD but correlated with plasma leptin only in LD. Amounts of leptin entering CSF after iv leptin injection were greater in LD than SD. In a separate experiment, plasma ( but not CSF) leptin was higher in fat than thin sheep in natural summer LD and after 5 wk in SD. CSF leptin correlated with plasma leptin in LD but not SD. CSF leptin after iv leptin injection was higher in thin than fat sheep but only in LD. Endogenous CSF to plasma concentration ratios correlated negatively with plasma concentrations, indicating decreased blood-brain transport with increased leptinemia. Therefore, icv ( and not iv) leptin inhibited appetite only in SD and decreased GnRH/LH output in both photoperiods, and the proportion of circulating leptin entering CSF was higher in LD and thinner animals. Photoperiod apparently modulates intrahypothalamic leptin sensitivity of appetite, but not reproductive, regulatory pathways, whereas photoperiod and leptinemia influence leptin blood-brain transport.

KW - LUTEINIZING-HORMONE SECRETION

KW - CEREBROSPINAL FLUID BARRIER

KW - MATURE MALE SHEEP

KW - LH-SECRETION

KW - FOOD-INTAKE

KW - PHODOPUS-SUNGORUS

KW - GROWTH-HORMONE

KW - CHOROID-PLEXUS

KW - PLASMA LEPTIN

KW - FEED-INTAKE

U2 - 10.1210/en.2006-0576

DO - 10.1210/en.2006-0576

M3 - Article

VL - 147

SP - 4589

EP - 4598

JO - Endocrinology

JF - Endocrinology

SN - 0013-7227

IS - 10

ER -