title: Gender-specific orexigenic and anorexigenic mechanisms in rats.
abstract: Feeding dysregulation may manifest as either under-nourishment (e.g., anorexia) or excessive eating leading to obesity. Recent studies have suggested a gender-related variance in weight maintenance in response to chronic disease or obesity-related dietary regimens. However it is unclear whether these gender differences in weight management are secondary to appetite-mediated food intake or alternative mechanisms (e.g., exercise, metabolism). In this study, we explored gender-dependent feeding and hormonal responses to dietary restriction (12-h fast) or to an inflammatory stimulus (LPS, 100 microg/kg b.w.; i.p.) in rats. In response to a 12 h fast, female rats increased (p<0.05) total daily food intake above that of male rats by primarily increasing nighttime feeding by 40%, as compared to 10% in males. Consistent with the increased food intake, fasting induced a greater percent increase in female as compared to male plasma ghrelin (141 vs. 65%, p<0.001). In response to LPS, both male and female rats showed similar reductions in total daily food consumption. However LPS (6 h) induced a greater percent increase in plasma leptin in female than male rats (230 vs. 33%, p<0.01), whereas ghrelin was similarly decreased in both females and males (66 vs. 44%). These findings demonstrate sexual dimorphic responses in feeding and appetite-associated hormonal responses to fasting or LPS treatment. Our findings suggest that therapeutic interventions with ghrelin or leptin must be modified according to gender in order to optimally achieve either weight loss for obesity or weight gain/maintenance for chronic illness-associated anorexia.
authors.affiliation: Department of Obstetrics and Gynecology, David Geffen School of Medicine at UCLA and Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance CA 90502, United States. dgayle@ucla.edu <dgayle@ucla.edu>
authors.forename: Dave A
authors.initials: DA
authors.lastname: Gayle
authors.forename: Mina
authors.initials: M
authors.lastname: Desai
authors.forename: Ederlen
authors.initials: E
authors.lastname: Casillas
authors.forename: Ron
authors.initials: R
authors.lastname: Beloosesky
authors.forename: Michael G
authors.initials: MG
authors.lastname: Ross
mesh_terms: D000818:Animals; D000855:Anorexia / Q000097:blood / Q000209:etiology*; D001066:Appetite / Q000187:drug effects / Q000502:physiology*; D001835:Body Weight / Q000502:physiology*; D005215:Fasting / Q000502:physiology*; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D005260:Female; D054439:Ghrelin; D020738:Leptin / Q000097:blood; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D036361:Peptide Hormones / Q000097:blood; D051381:Rats; D017207:Rats, Sprague-Dawley; D012737:Sex Factors
chemical_list: D054439:Ghrelin; D020738:Leptin; D008070:Lipopolysaccharides; D036361:Peptide Hormones