Sex differences in feeding behavior in rats: the relationship with neuronal activation in the hypothalamus

Abstract

There is general agreement that the central nervous system in rodents differs between sexes due to the presence of gonadal steroid hormone during differentiation. Sex differences in feeding seem to occur among species, and responses to fasting (i.e., starvation), gonadal steroids (i.e., testosterone and estradiol), and diet (i.e., western-style diet) vary significantly between sexes. The hypothalamus is the center for controlling feeding behavior. We examined the activation of feeding-related peptides in neurons in the hypothalamus. Phosphorylation of cyclic AMP response element-binding protein (CREB) is a good marker for neural activation, as is the Fos antigen. Therefore, we predicted that sex differences in the activity of melanin-concentrating hormone (MCH) neurons would be associated with feeding behavior. We determined the response of MCH neurons to glucose in the lateral hypothalamic area (LHA) and our results suggested MCH neurons play an important role in sex differences in feeding behavior. In addition, fasting increased the number of orexin neurons harboring phosphorylated CREB in female rats (regardless of the estrous day), but not male rats. Glucose injection decreased the number of these neurons with phosphorylated CREB in fasted female rats. Finally, under normal spontaneous food intake, MCH neurons, but not orexin neurons, expressed phosphorylated CREB. These sex differences in response to fasting and glucose, as well as under normal conditions, suggest a vulnerability to metabolic challenges in females.

Bigger doesn’t mean bolder: Behavioral variation of four wild rodent species to novelty and predation risk following a fast-slow continuum

“…Therefore, males may have a higher propensity to expose themselves to risk in return for a reward [22]; in the case of the present study, risk of exposure in an unfamiliar environment and a reward of access to food. Male rodents are generally larger than females [36,50], therefore, they may also have a higher food intake potential [53], as was observed in the present study. Overall, the defensive behavior concealing was higher for females, which indicates that in response to a novel, unfamiliar situation females exercised more caution.…”

How does sex matter? Behavior, stress and animal models of neurobehavioral disorders

“…Indeed, the analysis of non reproductive behavior of several mammalian species show sex differences in infant play, aggression, learning, exploration, activity level, behavioral circadian rythms, food intake and preference, novelty seeking, impulsivity, emotional behavior, cognitive ability and many more (Archer, 1975;Brain et al, 1991;Palanza, 2001;Alexander and Hines, 2002;Dalla and Shors, 2009;ter Horst et al, 2012;Lonsdorf et al, 2014;Argue and McCarthy, 2015;Krizo and Mintz, 2014;Fukushima et al, 2015;Carroll and Smethells, 2015) However, sex differences are not identical across species, as they depends upon specific, socio-ecological selective pressures that had acted during evolution. For example in laboratory rats and mice, females are more active and less anxious in several tests than males, but such a sex difference varies depending upon context, strain and age (Johnson and File, 1991;Palanza et al, 2001;An et al, 2011;ter Horst et al, 2012;Gioiosa et al, 2007Gioiosa et al, , 2013, while in other species of rodents, such as meadow voles, males are more active than females (Perrot-Sinal et al, 2000).…”

Effects of carrot puree with enhanced levels of chlorogenic acid on rat cognitive abilities and neural development

“…Furthermore, to better understand these results more studies evaluating a larger rodent population considering longer study duration, more generations and the effect of gender should be performed. Indeed, the latter (effect of gender) should be specially considered since although reports indicate that gender does not affect the gut microbiota (Lay et al, 2005), other authors have reported that gender affect gut microbiota, metabolism and neural system (Bridgewater et al, 2017;Bullock, Gemzik, Johnson, Thomast, & Parkinson, 1991;Czerniak, 2001;Fukuno, Nagai, Horii, Yamamoto, & Konishi, 2018;Fukushima et al, 2015;Jasarevic´, Morrison, & Bale, 2016;Org et al, 2016), suggesting that compounds may undergo gender-dependent metabolism.…”