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Photoperiod regulates lean mass accretion, but not adiposity, in growing F344 rats fed a high fat diet.

Ross AW, Russell L, Helfer G, Thomson LM, Dalby MJ, Morgan PJ - PLoS ONE (2015)

Bottom Line: On a high fat diet (HFD), containing 22.8% fat (45% energy as fat), food intake was reduced, but energy intake increased on both photoperiods.This implies that a primary effect of photoperiod is the regulation of growth and lean mass accretion.These data suggest that photoperiod and HFD influence body weight and body composition through independent mechanisms but in each case the role of the hypothalamic energy balance genes is not predictable based on their known function.

View Article: PubMed Central - PubMed

Affiliation: Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, Scotland, United Kingdom.

ABSTRACT
In this study the effects of photoperiod and diet, and their interaction, were examined for their effects on growth and body composition in juvenile F344 rats over a 4-week period. On long (16L:8D), relative to short (8L:16D), photoperiod food intake and growth rate were increased, but percentage adiposity remained constant (ca 3-4%). On a high fat diet (HFD), containing 22.8% fat (45% energy as fat), food intake was reduced, but energy intake increased on both photoperiods. This led to a small increase in adiposity (up to 10%) without overt change in body weight. These changes were also reflected in plasma leptin and lipid levels. Importantly while both lean and adipose tissue were strongly regulated by photoperiod on a chow diet, this regulation was lost for adipose, but not lean tissue, on HFD. This implies that a primary effect of photoperiod is the regulation of growth and lean mass accretion. Consistent with this both hypothalamic GHRH gene expression and serum IGF-1 levels were photoperiod dependent. As for other animals and humans, there was evidence of central hyposomatotropism in response to obesity, as GHRH gene expression was suppressed by the HFD. Gene expression of hypothalamic AgRP and CRH, but not NPY nor POMC, accorded with the energy balance status on long and short photoperiod. However, there was a general dissociation between plasma leptin levels and expression of these hypothalamic energy balance genes. Similarly there was no interaction between the HFD and photoperiod at the level of the genes involved in thyroid hormone metabolism (Dio2, Dio3, TSHβ or NMU), which are important mediators of the photoperiodic response. These data suggest that photoperiod and HFD influence body weight and body composition through independent mechanisms but in each case the role of the hypothalamic energy balance genes is not predictable based on their known function.

No MeSH data available.


Related in: MedlinePlus

Effect of photoperiod and high fat diet (HFD) on serum IGF-1 and pituitary growth hormone (GH) levels in juvenile F344 rats after, 4 weeks of treatment.(a) IGF-1 levels in serum were lower in SD chow and HFD fed rats than LD chow fed while LD HFD fed rats were not significantly different. (b) Growth hormone levels in the pituitary were unaffected by either photoperiod or HFD.
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pone.0119763.g005: Effect of photoperiod and high fat diet (HFD) on serum IGF-1 and pituitary growth hormone (GH) levels in juvenile F344 rats after, 4 weeks of treatment.(a) IGF-1 levels in serum were lower in SD chow and HFD fed rats than LD chow fed while LD HFD fed rats were not significantly different. (b) Growth hormone levels in the pituitary were unaffected by either photoperiod or HFD.

Mentions: Serum IGF-1 levels were 21.4% lower in F344 rats fed chow diets and exposed to SD for 4 weeks relative to LD treated animals (p<0.05). There was no difference in this response for animals given the HFD (Fig. 5a).


Photoperiod regulates lean mass accretion, but not adiposity, in growing F344 rats fed a high fat diet.

Ross AW, Russell L, Helfer G, Thomson LM, Dalby MJ, Morgan PJ - PLoS ONE (2015)

Effect of photoperiod and high fat diet (HFD) on serum IGF-1 and pituitary growth hormone (GH) levels in juvenile F344 rats after, 4 weeks of treatment.(a) IGF-1 levels in serum were lower in SD chow and HFD fed rats than LD chow fed while LD HFD fed rats were not significantly different. (b) Growth hormone levels in the pituitary were unaffected by either photoperiod or HFD.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4366045&req=5

pone.0119763.g005: Effect of photoperiod and high fat diet (HFD) on serum IGF-1 and pituitary growth hormone (GH) levels in juvenile F344 rats after, 4 weeks of treatment.(a) IGF-1 levels in serum were lower in SD chow and HFD fed rats than LD chow fed while LD HFD fed rats were not significantly different. (b) Growth hormone levels in the pituitary were unaffected by either photoperiod or HFD.
Mentions: Serum IGF-1 levels were 21.4% lower in F344 rats fed chow diets and exposed to SD for 4 weeks relative to LD treated animals (p<0.05). There was no difference in this response for animals given the HFD (Fig. 5a).

Bottom Line: On a high fat diet (HFD), containing 22.8% fat (45% energy as fat), food intake was reduced, but energy intake increased on both photoperiods.This implies that a primary effect of photoperiod is the regulation of growth and lean mass accretion.These data suggest that photoperiod and HFD influence body weight and body composition through independent mechanisms but in each case the role of the hypothalamic energy balance genes is not predictable based on their known function.

View Article: PubMed Central - PubMed

Affiliation: Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, Scotland, United Kingdom.

ABSTRACT
In this study the effects of photoperiod and diet, and their interaction, were examined for their effects on growth and body composition in juvenile F344 rats over a 4-week period. On long (16L:8D), relative to short (8L:16D), photoperiod food intake and growth rate were increased, but percentage adiposity remained constant (ca 3-4%). On a high fat diet (HFD), containing 22.8% fat (45% energy as fat), food intake was reduced, but energy intake increased on both photoperiods. This led to a small increase in adiposity (up to 10%) without overt change in body weight. These changes were also reflected in plasma leptin and lipid levels. Importantly while both lean and adipose tissue were strongly regulated by photoperiod on a chow diet, this regulation was lost for adipose, but not lean tissue, on HFD. This implies that a primary effect of photoperiod is the regulation of growth and lean mass accretion. Consistent with this both hypothalamic GHRH gene expression and serum IGF-1 levels were photoperiod dependent. As for other animals and humans, there was evidence of central hyposomatotropism in response to obesity, as GHRH gene expression was suppressed by the HFD. Gene expression of hypothalamic AgRP and CRH, but not NPY nor POMC, accorded with the energy balance status on long and short photoperiod. However, there was a general dissociation between plasma leptin levels and expression of these hypothalamic energy balance genes. Similarly there was no interaction between the HFD and photoperiod at the level of the genes involved in thyroid hormone metabolism (Dio2, Dio3, TSHβ or NMU), which are important mediators of the photoperiodic response. These data suggest that photoperiod and HFD influence body weight and body composition through independent mechanisms but in each case the role of the hypothalamic energy balance genes is not predictable based on their known function.

No MeSH data available.


Related in: MedlinePlus