Sex differences in diurnal rhythms of food intake in mice caused by gonadal hormones and complement of sex chromosomes - PubMed (original) (raw)

Sex differences in diurnal rhythms of food intake in mice caused by gonadal hormones and complement of sex chromosomes

Xuqi Chen et al. Horm Behav. 2015 Sep.

Abstract

We measured diurnal rhythms of food intake, as well as body weight and composition, while varying three major classes of sex-biasing factors: activational and organizational effects of gonadal hormones, and sex chromosome complement (SCC). Four Core Genotypes (FCG) mice, comprising XX and XY gonadal males and XX and XY gonadal females, were either gonad-intact or gonadectomized (GDX) as adults (2.5months); food intake was measured second-by-second for 7days starting 5weeks later, and body weight and composition were measured for 22weeks thereafter. Gonadal males weighed more than females. GDX increased body weight/fat of gonadal females, but increased body fat and reduced body weight of males. After GDX, XX mice had greater body weight and more fat than XY mice. In gonad-intact mice, males had greater total food intake and more meals than females during the dark phase, but females had more food intake and meals and larger meals than males during the light phase. GDX reduced overall food intake irrespective of gonad type or SCC, and eliminated differences in feeding between groups with different gonads. Diurnal phase of feeding was influenced by all three sex-biasing variables. Gonad-intact females had earlier onset and acrophase (peak) of feeding relative to males. GDX caused a phase-advance of feeding, especially in XX mice, leading to an earlier onset of feeding in GDX XX vs. XY mice, but earlier acrophase in GDX males relative to females. Gonadal hormones and SCC interact in the control of diurnal rhythms of food intake.

Keywords: Adiposity; Body composition; Circadian rhythm; Estradiol; Food intake; Four Core Genotypes; Night eating; Obesity; Sex chromosomes; Sex differences; Testosterone.

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Figures

Fig. 1

Body weight and composition in gonad-intact and GDX mice. Mice were GDX or not at 75 days of age (10 weeks) and then measured until 30–32 weeks of age. A. Body weight. B. Body fat expressed as percentage of body weight. C. Lean mass expressed as percent of body weight. F, gonadal female. M, gonadal male. On right side are final measurements at 32 weeks of age for body weight, or body fat and lean mass at 30 weeks of age. Group size is shown at the bottom of histogram bars. Results of the 3-way ANOVA for all groups (horizontal line above spanning all groups), and of 2-way ANOVAs for gonad-intact alone or GDX alone (horizontal lines above spanning only each condition), indicate significant effects (when present) of G (gonadal status, intact vs. GDX), S (gonadal sex, female vs. male), or C (sex chromosome complement, XX vs. XY). Significant interactions are shown as GxS, GxC, SxC, or GxSxC, * p<0.05, ** p<0.01, *** p<0.001, † p<0.0001, ‡ p<0.00001.

Fig. 2

Food intake measured in BioDAQ cages. A. Total food intake measured over the dark phase, light phase, or summer over 24 hours. B. Meal number. C. Meal size. D. Inter-meal interval. Results of the 3-way ANOVA for all groups (horizontal line above spanning all groups), and of 2-way ANOVAs for gonad-intact alone or GDX alone (horizontal lines above spanning only each condition), indicate significant effects (when present) of G (gonadal status, intact vs. GDX), S (gonadal sex, female vs. male), or C (sex chromosome complement, XX vs. XY). Significant interactions are shown as GxS, GxC, SxC, or GxSxC, * p<0.05, ** p<0.01, *** p<0.001, † p<0.0001, ‡ p<0.00001.

Fig. 3

Effects of gonadal sex and sex chromosome complement on diurnal rhythms of food intake. Food intake was averaged for each hour for 7 days for n=8 mice per condition. A. Gonad-intact females vs. males. B. Gonad-intact XX vs. XY. C. Gondectomized females vs. males. D. Gonadectomized XX vs. XY.

Fig. 4

Effects of gonadectomy on diurnal rhythms of food intake of mice differing in gonadal sex or sex chromosome complement. Food intake was averaged for each hour for 7 days for n=8 mice per condition. These curves are the same as in Fig. 3, but are re-graphed for direct assessment of the effects of GDX, A. Female intact vs. GDX. B. Male intact vs. GDX. C. XX intact vs. GDX. D. XY intact vs. GDX.

Fig. 5

Diurnal parameters of food intake. A. Power, a measure of the strength of the rhythm. B. Onset of food intake. C. Acrophase or peak of feeding rhythm. Zeitgeber Time (ZT) of 0 represents the time of lights on (6AM) and ZT 12 represents lights off (6PM) during a 24-hour day. Results of the 3-way ANOVA for all groups (horizontal line above spanning all groups), and of 2-way ANOVAs for gonad-intact alone or GDX alone (horizontal lines above spanning only each conditions), indicate significant effects (when present) of G (gonadal status, intact vs. GDX), S (gonadal sex, female vs. male), or C (sex chromosome complement, XX vs. XY). Significant interactions are shown as GxS, GxC, SxC, or GxSxC, * p<0.05, ** p<0.01, *** p<0.001, † p<0.0001, ‡ p<0.00001

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Sex differences in diurnal rhythms of food intake in mice caused by gonadal hormones and complement of sex chromosomes - PubMed (original) (raw)