Energy Balance and Reproduction. BioScience in the 21st Century Candice M. Klingerman 03 October 2011

Transcription

1 Energy Balance and Reproduction BioScience in the 21st Century Candice M. Klingerman 03 October 2011

2 Outline Energy balance Sex and food in conflict Sex and ingestive behavior Motivation is more sensitive to energy than performance Chemical messengers affect sex and ingestive behavior

3 Outline Energy balance Sex and food in conflict Sex and ingestive behavior Motivation is more sensitive to energy than performance Chemical messengers affect sex and ingestive behavior

4 Energetic Demands Cells need a constant supply of energy Cannot eat all of the time. Need time for other activities: Foraging for food Mating, caring for offspring Defending territory, working Energy is not constantly available so must be able to store

5 Energy Balance Energy Expenditure Cellular processes Thermoregulation Activity Growth Immune function Reproduction Food Intake Energy Storage Internally (fat, muscle) Externally (hoard) Adapted from Schneider 2007

6 Food Energy is acquired from food Food consists of macronutrients Fat Carbohydrates Protein Fat & carbohydrates glucose free fatty acids & Oxidized Free fatty acids and glucose energy (ATP)

7 Food Macronutrients (Fat, carbs, protein) Metabolic Fuels Glucose oxidation Fatty acid oxidation ATP Adapted from Schneider 2007

8 Adapted from Schneider, 2007

9 Block Fuel Oxidation Food Intake Fatty Acids Glucose Darling and Ritter, 2009

10 Food Intake Signals Primary sensory signals Gut distention Vagus nerve Secondary sensory signals Hormones and neuropeptides that affect food intake

11 Central Sensors Hypothalamus is important, but not required for control of food intake Decerebrate rats still increase food intake in response to inhibitors of metabolic fuel oxidation Caudal brainstem Similar inhibitors increase food intake when injected into the 4 th, but not 3 rd ventricle Lesions to area postrema and nucleus of the tractus solitarus attenuate effects of oxidation inhibitors

12 Peripheral Sensors Liver Vagotomy abolishes the effect of a fatty acid oxidation inhibitor (but not glucose inhibitor) on increasing food intake ATP storage Gut Contains mechanoreceptors Ghrelin Fat Leptin

13 Leptin Ghrelin Kollias, 2011

14 Energetic Demands Cells need a constant supply of energy Cannot eat all of the time. Need time for other activities Foraging for food Mating, caring for offspring Defending territory, working Energy is not constantly available so must be able to store

15 Outline Energy balance Sex and food in conflict Sex and ingestive behavior Motivation is more sensitive to energy than performance Chemical messengers affect sex and ingestive behavior

16 Behaviors in Conflict Sex Food Mechanism(s)?

17 Sex Behavior Courtship Scent marking Flank and vaginal Spending time with an opposite-sex conspecific Hopping and darting Mating Lordosis Presentation of rump Male hit rate (I/M)

18 Lordosis in the Syrian Hamster

19 Ingestive Behavior Foraging Eating Hoarding Humans vs hamsters Tom, 1983

20 Motivation & Performance Motivation Sexual Vaginal marking Time spent with a male vs. food Ingestive Food hoarding Performance Lordosis Eating, Food Intake

21 Outline Energy balance Sex and food in conflict Sex and ingestive behavior Motivation is more sensitive to energy than performance Chemical messengers affect sex and ingestive behavior

22 Food Restriction Dissociated SEXUAL Motivation From Performance Food Male Motivation Performance Home Days of Food Restriction Days of Re-feeding =TIME SIGNIFICANTLY LOWER THAN AD LIB * Different at P < 0.05 Klingerman et al., 2011

23 Food Restriction Dissociated INGESTIVE Motivation from Performance Motivation Performance N.S. Days of Food Restriction Days of Re-feeding =TIME SIGNIFICANTLY LOWER THAN AD LIB * Different at P < 0.05 Klingerman et al., 2011

24 Motivation Clearly Dissociated from Performance Mild food restriction significantly: Food hoarding Preference for males vs. food Has no effect on: Frequency or duration of lordosis Food intake (90 min or daily)

25 Outline Energy balance Sex and food in conflict Sex and ingestive behavior Motivation is more sensitive to energy than performance Chemical messengers affect sex and ingestive behavior

26 Things that Affect Sex & Ingestive Behaviors Energy restriction or deprivation Block glucose oxidation (2DG, 5TG) Block fatty acid oxidation (MP, MA) Chemical messengers Food: Neuropeptide Y, ghrelin, insulin, GnIH Sex: Leptin, estradiol, GnRH

27 Sex Food Chemical Messenger Ghrelin Gonadotropin-inhibiting hormone Leptin Estradiol Food Sex

28 Ghrelin Produced and secreted from cells in the stomach and pancreas in response to the absence of food Is also produced/secreted from the arcuate nucleus of the hypothalamus and controls growth hormone secretion from the pituitary

29 Circulating Ghrelin with Fasting Fasting Keen-Rhinehart and Bartness, 2004

30 Injections of Ghrelin Sex Behavior Food Intake and Food intake Sex behavior Small et al., 2000; Shah and Nyby, 2010

31 Sex Food Chemical Messenger Ghrelin Gonadotropin-inhibiting hormone Leptin Estradiol Food Sex

32 Leptin Produced/secreted from adipocytes Found in proportion to body fat Mutations in leptin or its receptor lead to hyperphagia and obesity O Rahilly et al., 2003

33 Circulating Leptin with Fasting 12 h Fast 24 h Fast Fasting Schneider, Blum, and Wade, 2000

34 Injections of Leptin Sex Behavior Vaginal scent marking Sexual performance Schneider et al., 2007

35 Injections of Leptin Behavior Ingestive No leptin Food hoarding Food intake Schneider et al., 2007; Mistry et al., 1997

36 Sex Food Chemical Messenger Ghrelin Gonadotropin-inhibiting hormone Leptin Estradiol Food Sex

37 Gonadotropin-inhibiting Hormone (GnIH) Released from dorsomedial nucleus of the hypothalamus May be involved in regulating reproductive cycles of seasonal breeding birds and mammals

38 Klingerman, Williams et al., in review Circulating GnIH with Fasting Fasting

39 Injections of GnIH Sex Behavior Ingestive Behavior Food intake Sex behavior Johnson et al., 2007; Bentley et al., 2006

40 Sex Food Chemical Messenger Ghrelin Gonadotropin-inhibiting hormone Leptin Estradiol Food Sex

41 Estradiol A hormone secreted from the ovary Circulating levels increase as ovulation is approaching Regulates sex behavior

42 Circulating Estradiol Food intake Estradiol rising Estradiol rising Caloric intake Fessler, 2003

43 Injections of Estradiol Food intake Asarian and Geary, 2002

44 Injections of Estradiol Sex Behavior Frequency of Vaginal Marks Vaginal Marking Lordosis Lisk and Nachtigall, 1988; Meisel et al., 1988

45 Sex Food Chemical Messenger Ghrelin Gonadotropin-inhibiting hormone Leptin Estradiol Food Sex

46 Summary Cells need a constant supply of energy. We cannot eat all of the time Mechanism(s) capable of monitoring internal and external energy. Peptide systems? Sex and ingestive behaviors are affected by energy. Motivation more sensitive than performance Chemical messengers that ingestive behavior, sex behavior

47 Take Home Message: Food Sex Food Sex

48 Recommended Publications Klingerman CM, Krishnamoorthy K, Patel K, Spiro AB, Struby C, Patel A, Schneider JE. Energetic challenges unmask the role of ovarian hormones in orchestrating ingestive and sex behaviors. Hormones and Behavior 2010; 58: Food Klingerman, CM, Patel, A, Hedges, VL, Meisel, RL, and Schneider., JE. Food restriction dissociates sexual motivation, sexual performance, and the rewarding consequences of copulation in female Syrian hamsters. Behavioral Brain Research 2011; 223: Wade GN. and Schneider JE. Metabolic fuels and reproduction in female mammals. Neuroscience and Biobehavioral Reviews. 1992; 16: Jones JE, Pick RR, Dettloff SL, Wade GN. Metabolic fuels, neuropeptide Y, and estrous behavior in Syrian hamsters. Brain Research. 2004; 1007: Morin LP. Effects of various feeding regimens and photoperiod or pinealectomy on ovulation in the hamster. Biology of Reproduction 1975; 13: Sex