The effects of puberty and ovarian hormone removal on developmental trajectories of palatable food and chow intake in female rats

Abstract

Objective: Palatable food (PF) intake is significantly greater in females than males and increases during adolescence. Previous data suggest that puberty and ovarian hormones may contribute to these sex and developmental differences, but few studies have examined this possibility. The aim of the current study was to address these gaps by examining trajectories of PF and chow intake during pre-puberty, puberty, and adulthood in intact female rats (Study 1) as well as in those receiving pre-pubertal ovariectomies (P-OVX) (Study 2). Method: We examined our study aims using archival data from 66 intact Sprague-Dawley female rats (Study 1) and 77 P-OVX and 79 intact Sprague-Dawley female rats (Study 2). PF and chow intake were measured using a free-choice, intermittent exposure paradigm in which rats were exposed to both food types starting in pre-puberty and continuing into adulthood. Results: Mixed linear models revealed a specific effect of puberty on PF intake in both studies. PF intake increased substantially during puberty in all rats, but increases were particularly pronounced in P-OVX rats in Study 2. By contrast, chow intake increased significantly during pre-puberty (rather than puberty) in both studies, and these increases were relatively unaffected by P-OVX. Discussion: Findings confirm a specific effect of puberty and ovarian hormone removal on PF intake in female rats. Differential trajectories of PF versus chow intake highlight potential reward-based processes in pubertal and ovarian hormone effects on PF intake in females.