Abstract
Sheep exhibit photoperiod-driven seasonal changes in appetite and body weight so that nutritional status increases in long days (LD) and decreases in short days (SD); additionally, they are reproductively active in SD and inactive in LD. We addressed the hypothesis that appetite-regulatory genes in the hypothalamus respond differently to changes in nutritional feedback induced by photoperiod as opposed to food restriction, and that responses would be influenced by gonadal steroid status. Castrated oestradiol-implanted male sheep were kept in SD (8 h light/day) or LD (16 It light/day) for 11 weeks, with ad libitum or restricted food (experiment 1; n = 8/group). Rams were kept in SD or LD for 12 weeks with ad libitum or restricted food (experiment 2; n = 6/group). Gene expression (by in situ hybridisation) in the hypothalamic arcuate nucleus for leptin receptor (OB-Rb), neuropeptide Y (NPY), pro-opiomelanocortin (POMC) and agouti-related peptide (AGRP) was unaffected by photoperiod treatment, but food restriction increased NPY and AGRP mRNAs, in experiment 1. In experiment 2, mRNAs for POMC and cocaine- and amphetamine-regulated transcript (CART) were up-regulated and AGRP down-regulated in SD, while food restriction increased OB-Rb mRNA, increased NPY and AGRP mRNAs only in LD and decreased POMC mRNA only in SD. Thus, gene expression responded differently to photoperiod and food restriction, and the melanocortin pathway was up-regulated in SD in reproductively activated rams but not in oestradiol-implanted castrates. These data support the hypothesis that hypothalamic appetite-regulatory pathways respond differently to changes in nutritional feedback induced by photoperiod as opposed to food restriction, with gonadal steroid feedback additionally influencing the responses.
| Original language | English |
|---|---|
| Pages (from-to) | 409-419 |
| Number of pages | 11 |
| Journal | Journal of Endocrinology |
| Volume | 182 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Sep 2004 |
Keywords
- LUTEINIZING-HORMONE SECRETION
- NEUROPEPTIDE-Y
- FOOD-INTAKE
- LEPTIN RECEPTOR
- LH-SECRETION
- OVARIECTOMIZED EWES
- SIBERIAN HAMSTERS
- MESSENGER-RNA
- BODY-WEIGHT
- PHOTOPERIOD
- luteinizing-hormone secretion
- neuropeptide-Y
- food-intake
- leptin receptor
- LH-secretion
- ovareiectomized ewes
- Siberian hamsters
- messenger-RNA
- body-weight
- photoperiod
Cite this
Effects of nutritional status and gonadal steroids on expression of appetite-regulatory genes in the hypothalamic arcuate nucleus of sheep. / Archer, Z A ; Findlay, P.A. ; McMillen, S R ; Rhind, S M ; Adam, Clare Lesley.
In: Journal of Endocrinology, Vol. 182, No. 3, 09.2004, p. 409-419.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effects of nutritional status and gonadal steroids on expression of appetite-regulatory genes in the hypothalamic arcuate nucleus of sheep
AU - Archer, Z A
AU - Findlay, P.A.
AU - McMillen, S R
AU - Rhind, S M
AU - Adam, Clare Lesley
PY - 2004/9
Y1 - 2004/9
N2 - Sheep exhibit photoperiod-driven seasonal changes in appetite and body weight so that nutritional status increases in long days (LD) and decreases in short days (SD); additionally, they are reproductively active in SD and inactive in LD. We addressed the hypothesis that appetite-regulatory genes in the hypothalamus respond differently to changes in nutritional feedback induced by photoperiod as opposed to food restriction, and that responses would be influenced by gonadal steroid status. Castrated oestradiol-implanted male sheep were kept in SD (8 h light/day) or LD (16 It light/day) for 11 weeks, with ad libitum or restricted food (experiment 1; n = 8/group). Rams were kept in SD or LD for 12 weeks with ad libitum or restricted food (experiment 2; n = 6/group). Gene expression (by in situ hybridisation) in the hypothalamic arcuate nucleus for leptin receptor (OB-Rb), neuropeptide Y (NPY), pro-opiomelanocortin (POMC) and agouti-related peptide (AGRP) was unaffected by photoperiod treatment, but food restriction increased NPY and AGRP mRNAs, in experiment 1. In experiment 2, mRNAs for POMC and cocaine- and amphetamine-regulated transcript (CART) were up-regulated and AGRP down-regulated in SD, while food restriction increased OB-Rb mRNA, increased NPY and AGRP mRNAs only in LD and decreased POMC mRNA only in SD. Thus, gene expression responded differently to photoperiod and food restriction, and the melanocortin pathway was up-regulated in SD in reproductively activated rams but not in oestradiol-implanted castrates. These data support the hypothesis that hypothalamic appetite-regulatory pathways respond differently to changes in nutritional feedback induced by photoperiod as opposed to food restriction, with gonadal steroid feedback additionally influencing the responses.
AB - Sheep exhibit photoperiod-driven seasonal changes in appetite and body weight so that nutritional status increases in long days (LD) and decreases in short days (SD); additionally, they are reproductively active in SD and inactive in LD. We addressed the hypothesis that appetite-regulatory genes in the hypothalamus respond differently to changes in nutritional feedback induced by photoperiod as opposed to food restriction, and that responses would be influenced by gonadal steroid status. Castrated oestradiol-implanted male sheep were kept in SD (8 h light/day) or LD (16 It light/day) for 11 weeks, with ad libitum or restricted food (experiment 1; n = 8/group). Rams were kept in SD or LD for 12 weeks with ad libitum or restricted food (experiment 2; n = 6/group). Gene expression (by in situ hybridisation) in the hypothalamic arcuate nucleus for leptin receptor (OB-Rb), neuropeptide Y (NPY), pro-opiomelanocortin (POMC) and agouti-related peptide (AGRP) was unaffected by photoperiod treatment, but food restriction increased NPY and AGRP mRNAs, in experiment 1. In experiment 2, mRNAs for POMC and cocaine- and amphetamine-regulated transcript (CART) were up-regulated and AGRP down-regulated in SD, while food restriction increased OB-Rb mRNA, increased NPY and AGRP mRNAs only in LD and decreased POMC mRNA only in SD. Thus, gene expression responded differently to photoperiod and food restriction, and the melanocortin pathway was up-regulated in SD in reproductively activated rams but not in oestradiol-implanted castrates. These data support the hypothesis that hypothalamic appetite-regulatory pathways respond differently to changes in nutritional feedback induced by photoperiod as opposed to food restriction, with gonadal steroid feedback additionally influencing the responses.
KW - LUTEINIZING-HORMONE SECRETION
KW - NEUROPEPTIDE-Y
KW - FOOD-INTAKE
KW - LEPTIN RECEPTOR
KW - LH-SECRETION
KW - OVARIECTOMIZED EWES
KW - SIBERIAN HAMSTERS
KW - MESSENGER-RNA
KW - BODY-WEIGHT
KW - PHOTOPERIOD
KW - luteinizing-hormone secretion
KW - neuropeptide-Y
KW - food-intake
KW - leptin receptor
KW - LH-secretion
KW - ovareiectomized ewes
KW - Siberian hamsters
KW - messenger-RNA
KW - body-weight
KW - photoperiod
U2 - 10.1677/joe.0.1820409
DO - 10.1677/joe.0.1820409
M3 - Article
VL - 182
SP - 409
EP - 419
JO - Journal of Endocrinology
JF - Journal of Endocrinology
SN - 0022-0795
IS - 3
ER -