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Estradiol decreases the orexigenic strength of the melanin concentrating hormone (MCH) system through indirect changes in MCH and MCH receptor (MCHR1) protein expression
Abstracts / Appetite 54 (2010) 631–683
Role of social influence in childhood obesity S.J. SALVY Unmiversity at Buffalo, Buffalo, NY, USA There is emerging evidence that youth’s social network may be uniquely relevant and influential to eating behavior and choice of activities. Individuals are influenced by the eating and activity norms set by those around them and friendship and peer relationships can either maintain obesigenic behaviors or reinforce healthier eating and activity habits. This oral presentation, consisting of descriptions of laboratory and field studies, summarizes the research on the effects of social influence on the control of intake (food consumption), food selection (with an emphasis on food choices and preferences) and choices of sedentary and physically active leisure activities. Drawing from these findings and from the work of others we contend that decreasing sedentary behavior and increasing active leisure activities may require the social structure of meaningful relationships with friends, as friendship may help to promote or “socialize” active lifestyles. Attempts to substitute physical activity for sedentary behavior may not be effective if problematic peer relationships persist, in part because sedentary activities are more reinforcing, easily accessible, easily performed alone and less threatening for socially isolated youths. Conceivably, the involvement of children’s social ecology in prevention efforts is a promising approach to set the stage for health trajectories. doi:10.1016/j.appet.2010.04.176
Estradiol decreases the orexigenic strength of the melanin concentrating hormone (MCH) system through indirect changes in MCH and MCH receptor (MCHR1) protein expression J. SANTOLLO ∗ , L.A. ECKEL Florida State University, Tallahassee, FL, USA Previously, we demonstrated that MCH-induced feeding is decreased by the rise in estradiol secretion in cycling rats and by estradiol treatment in ovariectomized (OVX) rats. Because estradiol binds to nuclear estrogen receptors (ERs) that are capable of influencing gene expression, we hypothesized that estradiol suppresses MCH signaling by decreasing MCH and/or MCHR1 expression. In support of this hypothesis, both endogenous and exogenous estradiol reduced hypothalamic MCH and MCHR1 protein expression (assessed via immunocytochemistry (ICC) and western blot) in cycling and OVX rats, respectively (Ps < 0.05). In a second experiment, we determined whether these actions of estradiol occur at the level of the MCH/MCHR1 gene. Estradiol (10 nM) was directly applied to a neuronal, hypothalamic, cell line (N-42) that expresses ERs, MCH and MCHR1. We found, however, that estradiol failed to decrease either MCH or MCHR1 gene expression in vitro. This finding was further supported by a subsequent experiment involving in vivo ICC in which we determined that while MCH and ER␣ are both expressed in the lateral hypothalamus (LH) and zona incerta, they are not co-localized within the same neurons. In a final experiment, we determined that microinfusions of 2.5 g estradiol directly into the LH failed to decrease MCH’s orexigenic effect in OVX rats. Taken together, these studies demonstrate that estradiol decreases MCH signaling by decreasing MCH and MCHR1 protein expression via an indirect mechanism residing outside of the LH. doi:10.1016/j.appet.2010.04.177
673
Pilot intervention promoting responsive feeding, the division of feeding responsibility, and healthy dietary choices during infancy J.S. SAVAGE 1,2,∗ , I.M. PAUL 1,3 , M.E. MARINI 1,2 , L.L. BIRCH 1,2 1 Penn State University, University Park, PA, USA 2 Center for Childhood Obesity Research, University Park, PA, USA 3 Hershey Medical Center, Hershey, PA, USA Parents’ feeding practices play a critical role in the development of children’s food preferences and dietary intake. This research examined the effect of a behavioral intervention designed to teach parents about responsive feeding, division of feeding responsibility, and making healthy dietary choices. Mother–infant dyads (n = 110) intending to breastfeed were randomized to receive an intervention that taught parents about the timing and methods for the introduction of solids and how to overcome food neophobia, using repeated exposure to improve liking and acceptance of unfamiliar foods such as vegetables. Parents reported when complementary foods were introduced. Infant feeding video-taped data were collected at age 1. Results revealed that only 17% of the intervention group introduced solids before 4 months of age compared with 34% of the control subjects (p = 0.06). More babies in the intervention group (42%) did not consume desserts or sweets in the past week compared to the control. Within the intervention group, infants showed significantly greater consumption of green beans (p < 0.001), peas (p < 0.05), and squash (p < 0.05) from the first to last day of exposure. At 1 year, only 10% of infants in the intervention group rejected an unfamiliar food at age 1 year compared to 25% of the control group (p < 0.05). These findings indicate that this behavioral intervention successfully trained parents to delay the introduction of solids and increased infant acceptance of vegetables and novel foods. doi:10.1016/j.appet.2010.04.178
Personality as a risk factor for developing obesity and insulin resistance A.J.W. SCHEURINK ∗ , G.J. BOERSMA Department of Neuroendocrinology, University of Groningen, Groningen, Netherlands We investigated the interactions between personality and diet as risk factors for developing insulin resistance and hypothesized that rats characterized by a passive coping style are more susceptible for developing insulin resistance and visceral obesity than proactive coping rats. This hypothesis was tested by comparing insulin and glucose responses to an intravenous glucose tolerance test (IVGTT) and body fat distribution in passive and proactive personalities from two different rat strains (Roman High and Low Avoidance rats and Wild Type Groningen rats). We found that the most extremely passive individuals are characterized by elevated insulin levels during a IVGTT, even on chow. Moderate passive individuals display normal insulin responses under chow conditions, but develop insulin resistance on a palatable medium fat (45%) diet. Carcass analysis revealed that passive individuals are also characterized by increased epididymal fat deposition. Proactive individuals are remarkably resistant to insulin resistance and visceral obesity, even when overfeeding on a medium fat diet. We conclude that a passive personality is prone to develop insulin resistance and visceral obesity on a palatable fat diet and that a proactive personality might be protected against the development of diet-induced insulin resistance. In our most recent studies we investigated, both in rats and humans, whether personality may also serve as an important factor determining the success of life style intervention programs and found that in particular passive individuals may benefit from these programs. doi:10.1016/j.appet.2010.04.179
Role of social influence in childhood obesity S.J. SALVY Unmiversity at Buffalo, Buffalo, NY, USA There is emerging evidence that youth’s social network may be uniquely relevant and influential to eating behavior and choice of activities. Individuals are influenced by the eating and activity norms set by those around them and friendship and peer relationships can either maintain obesigenic behaviors or reinforce healthier eating and activity habits. This oral presentation, consisting of descriptions of laboratory and field studies, summarizes the research on the effects of social influence on the control of intake (food consumption), food selection (with an emphasis on food choices and preferences) and choices of sedentary and physically active leisure activities. Drawing from these findings and from the work of others we contend that decreasing sedentary behavior and increasing active leisure activities may require the social structure of meaningful relationships with friends, as friendship may help to promote or “socialize” active lifestyles. Attempts to substitute physical activity for sedentary behavior may not be effective if problematic peer relationships persist, in part because sedentary activities are more reinforcing, easily accessible, easily performed alone and less threatening for socially isolated youths. Conceivably, the involvement of children’s social ecology in prevention efforts is a promising approach to set the stage for health trajectories. doi:10.1016/j.appet.2010.04.176
Estradiol decreases the orexigenic strength of the melanin concentrating hormone (MCH) system through indirect changes in MCH and MCH receptor (MCHR1) protein expression J. SANTOLLO ∗ , L.A. ECKEL Florida State University, Tallahassee, FL, USA Previously, we demonstrated that MCH-induced feeding is decreased by the rise in estradiol secretion in cycling rats and by estradiol treatment in ovariectomized (OVX) rats. Because estradiol binds to nuclear estrogen receptors (ERs) that are capable of influencing gene expression, we hypothesized that estradiol suppresses MCH signaling by decreasing MCH and/or MCHR1 expression. In support of this hypothesis, both endogenous and exogenous estradiol reduced hypothalamic MCH and MCHR1 protein expression (assessed via immunocytochemistry (ICC) and western blot) in cycling and OVX rats, respectively (Ps < 0.05). In a second experiment, we determined whether these actions of estradiol occur at the level of the MCH/MCHR1 gene. Estradiol (10 nM) was directly applied to a neuronal, hypothalamic, cell line (N-42) that expresses ERs, MCH and MCHR1. We found, however, that estradiol failed to decrease either MCH or MCHR1 gene expression in vitro. This finding was further supported by a subsequent experiment involving in vivo ICC in which we determined that while MCH and ER␣ are both expressed in the lateral hypothalamus (LH) and zona incerta, they are not co-localized within the same neurons. In a final experiment, we determined that microinfusions of 2.5 g estradiol directly into the LH failed to decrease MCH’s orexigenic effect in OVX rats. Taken together, these studies demonstrate that estradiol decreases MCH signaling by decreasing MCH and MCHR1 protein expression via an indirect mechanism residing outside of the LH. doi:10.1016/j.appet.2010.04.177
673
Pilot intervention promoting responsive feeding, the division of feeding responsibility, and healthy dietary choices during infancy J.S. SAVAGE 1,2,∗ , I.M. PAUL 1,3 , M.E. MARINI 1,2 , L.L. BIRCH 1,2 1 Penn State University, University Park, PA, USA 2 Center for Childhood Obesity Research, University Park, PA, USA 3 Hershey Medical Center, Hershey, PA, USA Parents’ feeding practices play a critical role in the development of children’s food preferences and dietary intake. This research examined the effect of a behavioral intervention designed to teach parents about responsive feeding, division of feeding responsibility, and making healthy dietary choices. Mother–infant dyads (n = 110) intending to breastfeed were randomized to receive an intervention that taught parents about the timing and methods for the introduction of solids and how to overcome food neophobia, using repeated exposure to improve liking and acceptance of unfamiliar foods such as vegetables. Parents reported when complementary foods were introduced. Infant feeding video-taped data were collected at age 1. Results revealed that only 17% of the intervention group introduced solids before 4 months of age compared with 34% of the control subjects (p = 0.06). More babies in the intervention group (42%) did not consume desserts or sweets in the past week compared to the control. Within the intervention group, infants showed significantly greater consumption of green beans (p < 0.001), peas (p < 0.05), and squash (p < 0.05) from the first to last day of exposure. At 1 year, only 10% of infants in the intervention group rejected an unfamiliar food at age 1 year compared to 25% of the control group (p < 0.05). These findings indicate that this behavioral intervention successfully trained parents to delay the introduction of solids and increased infant acceptance of vegetables and novel foods. doi:10.1016/j.appet.2010.04.178
Personality as a risk factor for developing obesity and insulin resistance A.J.W. SCHEURINK ∗ , G.J. BOERSMA Department of Neuroendocrinology, University of Groningen, Groningen, Netherlands We investigated the interactions between personality and diet as risk factors for developing insulin resistance and hypothesized that rats characterized by a passive coping style are more susceptible for developing insulin resistance and visceral obesity than proactive coping rats. This hypothesis was tested by comparing insulin and glucose responses to an intravenous glucose tolerance test (IVGTT) and body fat distribution in passive and proactive personalities from two different rat strains (Roman High and Low Avoidance rats and Wild Type Groningen rats). We found that the most extremely passive individuals are characterized by elevated insulin levels during a IVGTT, even on chow. Moderate passive individuals display normal insulin responses under chow conditions, but develop insulin resistance on a palatable medium fat (45%) diet. Carcass analysis revealed that passive individuals are also characterized by increased epididymal fat deposition. Proactive individuals are remarkably resistant to insulin resistance and visceral obesity, even when overfeeding on a medium fat diet. We conclude that a passive personality is prone to develop insulin resistance and visceral obesity on a palatable fat diet and that a proactive personality might be protected against the development of diet-induced insulin resistance. In our most recent studies we investigated, both in rats and humans, whether personality may also serve as an important factor determining the success of life style intervention programs and found that in particular passive individuals may benefit from these programs. doi:10.1016/j.appet.2010.04.179