title: Food deprivation and leptin prioritize ingestive and sex behavior without affecting estrous cycles in Syrian hamsters.
abstract: Energy consumption is critical for the energetically expensive processes related to reproduction, and thus, mechanisms that increase ingestive behavior are directly linked to reproductive success. Similarly, the mechanisms that inhibit hunger and ingestive behavior might be most adaptive when these mechanisms cause individuals to stop foraging, hoarding and eating in order to find and court potential mates. In the laboratory, ingestive behaviors are typically studied separately from reproductive behaviors even though it is likely that these behaviors evolved under conditions in which both food and mates were available. We examined the choice between paracopulatory and ingestive behaviors in a semi-natural environment in which both food and potential mates were available. Intact female Syrian hamsters showed a high preference for males on days 3 and 4 (day 4 being the day of ovulation and estrous behavior), and a 48-h period of food deprivation significantly decreased preference for sex and increased preference for eating and food hoarding on day 3 in 89% of the hamsters, although none became anestrous. The same period of food deprivation significantly decreased the level of vaginal marking without significant effects on plasma estradiol concentrations. Next, hamsters were either food deprived (FD) or fed ad libitum, and half of each group was treated with vehicle or the adipocyte hormone leptin. The percentage of females with a low preference for sex was significantly greater in the FD compared to the ad libitum-fed groups, and leptin treatment prevented this effect. Metabolic fuels, possibly acting through leptin and other hormones, might influence sensitivity to estradiol or enhance the downstream effects of estradiol, thereby increasing motivation for sex and decreasing the relative motivation to forage, hoard and eat food.
authors.affiliation: Department of Biological Sciences, Lehigh University, 111 Research Drive, Bethlehem, PA 18015, USA. js0v@lehigh.edu
authors.forename: Jill E
authors.initials: JE
authors.lastname: Schneider
authors.forename: Janelle F
authors.initials: JF
authors.lastname: Casper
authors.forename: Amanda
authors.initials: A
authors.lastname: Barisich
authors.forename: Candace
authors.initials: C
authors.lastname: Schoengold
authors.forename: Sandeep
authors.initials: S
authors.lastname: Cherry
authors.forename: Justine
authors.initials: J
authors.lastname: Surico
authors.forename: Ashley
authors.initials: A
authors.lastname: DeBarba
authors.forename: Frank
authors.initials: F
authors.lastname: Fabris
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Rabold
mesh_terms: D000818:Animals; D006224:Cricetinae; D004435:Eating / Q000187:drug effects; D004958:Estradiol / Q000097:blood; D030762:Estrous Cycle / Q000187:drug effects; D005260:Female; D005508:Food Deprivation / Q000502:physiology*; D020738:Leptin / Q000494:pharmacology*; D008297:Male; D008647:Mesocricetus; D012726:Sexual Behavior, Animal / Q000187:drug effects; D013997:Time Factors
chemical_list: D020738:Leptin; D004958:Estradiol