Document Type

Thesis

Degree Name

Master of Science (MSc)

Department

Psychology

Program Name/Specialization

Behavioural Neuroscience

Faculty/School

Faculty of Science

First Advisor

Rudy Eikelboom

Advisor Role

Advisor

Abstract

Providing rats with running wheel access results in a short-term reduction in feeding and body weight relative to controls; known as the wheel-induced feeding suppression (WIFS). WIFS may parallel aspects of anorexia nervosa, an eating disorder that mostly affects females. Yet, most studies of WIFS and related models use male rats. The present study included female and male rats, where half were given wheel access to measure effects on feeding and body weight. Replication 1 females and Replication 2 males were in unisex housing. Replication 3 males and females were housed in same room. Rats were individually (IH) or pair housed (PH) as it may reduce stress and the WIFS. None of the replications found evidence that pair housing changed the WIFS. Females in Replication 1 had a shorter WIFS than Replication 2 males. In Replication 3, the WIFS was similar in both sexes. Pair housing affected wheel turn counts. Female PH rats ran in the wheel together, resulting in fewer wheel counts than for IH rats. PH males did not run together, resulting in equal or higher counts than IH males. Female wheel running and feeding were affected by the estrous cycle; running was elevated and feeding was reduced at estrus. The Whitten effect suggests that males can induce estrous cycle regularity and synchrony. In Replication 3, males induced estrous regularity and synchrony as seen in the wheel running and feeding of the females. The absence of males in Replication 1 led to reduced estrous regularity and synchrony. It is concluded that exercise has immediate and lasting effect on energy balance. Females regulate this energy balance differently than males, a difference possibly driven by gonadal hormones and by a number of factors in the environment. The sex differences in regulating energy balance can have important implications for eating disorders that are sexually dimorphic, like anorexia and even those of increased consumption, such as obesity.

Convocation Year

2013

Convocation Season

Fall

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