Department of Psychology, Michigan State University, East Lansing, MI 48824-1116, USA.
Department of Psychology, Michigan State University, East Lansing, MI 48824-1116, USA.
Physiol Behav. 2021 Jun 1;235:113394. doi: 10.1016/j.physbeh.2021.113394. Epub 2021 Mar 21.
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).
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.
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.
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.
女性摄入美味食物（PF）的量明显高于男性，并且在青春期会增加。先前的数据表明，青春期和卵巢激素可能是导致这些性别和发育差异的原因，但很少有研究对此进行了探讨。本研究旨在通过检查未成熟、青春期和成年期完整雌性大鼠（研究 1）以及接受青春期前卵巢切除术（P-OVX）的大鼠（研究 2）中 PF 和普通食物的摄入量轨迹来解决这些差距。
我们使用 66 只未成熟的 Sprague-Dawley 雌性大鼠的档案数据（研究 1）和 77 只 P-OVX 和 79 只完整的 Sprague-Dawley 雌性大鼠的档案数据（研究 2）来检查我们的研究目的。PF 和普通食物的摄入量是通过自由选择、间歇性暴露的范式来测量的，其中大鼠从青春期开始就可以接触到这两种食物类型，并持续到成年期。
混合线性模型显示青春期对两种研究中 PF 摄入量都有特定的影响。在所有大鼠中，PF 摄入量在青春期都会显著增加，但在研究 2 中 P-OVX 大鼠中的增加尤其明显。相比之下，在两项研究中，普通食物的摄入量在青春期前（而不是青春期）显著增加，而 P-OVX 对这些增加的影响相对较小。
研究结果证实了青春期和卵巢激素去除对雌性大鼠 PF 摄入量的特定影响。PF 与普通食物摄入量的不同轨迹突出了潜在的奖励机制，在青春期和卵巢激素对女性 PF 摄入量的影响中发挥作用。
