Lab Anim Res.  2013 Mar;29(1):1-6. 10.5625/lar.2013.29.1.1.

Serum leptin concentrations, leptin mRNA expression, and food intake during the estrous cycle in rats

• Fungfuang
• Nakada T
• Nakao N
• Terada M
• Yokosuka M
• Gizurarson S
• Hau J
• Moon C
• Saito TR

• KMID: 2312096
• DOI: http://doi.org/10.5625/lar.2013.29.1.1

Abstract

The aim of this study was to investigate food intake, serum leptin levels, and leptin mRNA expression during the sexual cycle in rats. Female Wistar-Imamichi rats aged 8-10 weeks were used in this experiment. Food intake was measured during the light and dark phases (light on at 07:00 and off at 19:00) of the 4-day estrous cycle in female rats. Serum leptin levels were measured by ELISA, and leptin mRNA expression levels were analyzed using real-time PCR on diestrous- and proestrous-stage rats. Our results revealed that during the sexual cycle, food intake was significantly higher in the dark phase compared with the light phase. Food intake in proestrous females was significantly lower in the light and dark phases compared with the other groups. Serum leptin concentrations were significantly higher in both phases in proestrous rats compared with diestrous rats. There was a significant increase in leptin mRNA expression in adipose tissue during the proestrous period compared with the diestrous period. These findings suggest that increased leptin mRNA expression and serum leptin levels, which are induced by estrogen during the proestrous stage, may play a role in regulating appetitive behavior.

Keyword

Estrous cycle; food intake; leptin

MeSH Terms

Adipose Tissue
Aged
Animals
Appetitive Behavior
Eating
Enzyme-Linked Immunosorbent Assay
Estrogens
Estrous Cycle
Female
Humans
Leptin
Light
Rats
Real-Time Polymerase Chain Reaction
RNA, Messenger
Estrogens
Leptin
RNA, Messenger

Figure

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  Figure 1 Food intake in intact female rats through the 4-day estrous cycle. Data are presented as means±SEM (n=6). The different characters indicate significant differences between the periods of estrous cycle (P<0.01).

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  Figure 2 Serum leptin concentration in intact female rats during the proestrous and diestrous periods. Data are presented as means±SEM (n=6). The different characters indicate significant differences between the periods of estrous cycle (P<0.01).

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  Figure 3 Leptin mRNA expression in adipose tissue during diestrous and proestrous. Data are presented means±SEM (n=6). The different characters indicate significant differences between the periods of estrous cycle (P<0.01).

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