Energy Balance and Reproduction - Lehigh University · 2011. 10. 3. · Recommended Publications Klingerman CM, Krishnamoorthy K, Patel K, Spiro AB, Struby C, Patel A, Schneider JE

Energy Balance and Reproduction

BioScience in the 21st Century Candice M. Klingerman

03 October 2011

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

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

Energy Balance

Food Intake

Energy Expenditure

• Cellular processes • Thermoregulation • Activity • Growth • Immune function • Reproduction

Energy Storage

• Internally (fat, muscle) • Externally (hoard)

Adapted from Schneider 2007

Food

• Energy is acquired from food • Food consists of macronutrients

– Fat – Carbohydrates – Protein

• Fat & carbohydrates free fatty acids & glucose – Free fatty acids and glucose energy (ATP)

Oxidized

Food

Macronutrients

Metabolic Fuels

Glucose oxidation

Fatty acid oxidation

ATP Adapted from Schneider 2007

(Fat, carbs, protein)

Adapted from Schneider, 2007

Block Fuel Oxidation Food Intake

Darling and Ritter, 2009

Fatty Acids Glucose

Food Intake Signals

• Primary sensory signals – Gut distention – Vagus nerve

• Secondary sensory signals – Hormones and neuropeptides that affect food

intake

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 4th, but not 3rd ventricle – Lesions to area postrema and nucleus of the tractus solitarus attenuate effects of oxidation inhibitors

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

Leptin Ghrelin

Kollias, 2011

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

Outline


than performance


Behaviors in Conflict

Sex Food

Mechanism(s)?

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)

Lordosis in the Syrian Hamster

Ingestive Behavior

• Foraging • Eating • Hoarding

– Humans vs hamsters

Tom, 1983

Motivation & Performance

Vaginal marking

Time spent with a male vs. food

Lordosis

Food hoarding

Eating, Food Intake

Motivation

Performance

Ingestive Sexual

Outline


than performance


Food Restriction Dissociated SEXUAL Motivation From Performance

Klingerman et al., 2011

Performance

Days of Food Restriction Days of Re-feeding

Motivation

* Different at P < 0.05

=TIME SIGNIFICANTLY LOWER THAN AD LIB

Food Male

Home

Food Restriction Dissociated INGESTIVE Motivation from Performance

Klingerman et al., 2011

N.S.

Performance

Days of Food Restriction Days of Re-feeding

Motivation

* Different at P < 0.05

=TIME SIGNIFICANTLY LOWER THAN AD LIB

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)

Outline


than performance


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

Sex Food

Food Sex Chemical Messenger

• Ghrelin

• Gonadotropin-inhibiting hormone

• Leptin

• Estradiol

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

Circulating Ghrelin with Fasting

Fasting

Keen-Rhinehart and Bartness, 2004

Injections of Ghrelin Food Intake and Sex Behavior

Small et al., 2000; Shah and Nyby, 2010

Food intake Sex behavior

Sex Food


• Ghrelin


• Leptin

• Estradiol

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

Circulating Leptin with Fasting

Fasting

12 h Fast 24 h Fast

Schneider, Blum, and Wade, 2000

Injections of Leptin Sex Behavior

Sexual performance

Schneider et al., 2007

Vaginal scent marking

Injections of Leptin Ingestive Behavior

Food intake

Schneider et al., 2007; Mistry et al., 1997

Food hoarding

No leptin

Sex Food


• Ghrelin


• Leptin

• Estradiol

Gonadotropin-inhibiting Hormone (GnIH)

• Released from dorsomedial nucleus of the hypothalamus

• May be involved in regulating reproductive cycles of seasonal breeding birds and mammals

Circulating GnIH with Fasting

Fasting

Klingerman, Williams et al., in review

Injections of GnIH Ingestive Behavior Sex Behavior

Food intake Sex behavior

Johnson et al., 2007; Bentley et al., 2006

Sex Food


• Ghrelin


• Leptin

• Estradiol

Estradiol

• A hormone secreted from the ovary • Circulating levels increase as ovulation is

approaching

• Regulates sex behavior

Circulating Estradiol Food intake

Fessler, 2003

Estradiol rising Estradiol rising

Calo

ric

inta

ke

Injections of Estradiol Food intake

Asarian and Geary, 2002

Injections of Estradiol Sex Behavior

Vaginal Marking Lordosis

Freq

uenc

y of

Vag

inal

Mar

ks

Lisk and Nachtigall, 1988; Meisel et al., 1988

Sex Food


• Ghrelin


• Leptin

• Estradiol

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

Take Home Message:

Food

Sex

Food

Sex

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; 58:563-74.

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; 223:356-370.

Wade GN. and Schneider JE. Metabolic fuels and reproduction in female mammals. Neuroscience and Biobehavioral Reviews. 1992; 16:235-272.

Jones JE, Pick RR, Dettloff SL, Wade GN. Metabolic fuels, neuropeptide Y, and estrous behavior in Syrian hamsters. Brain Research. 2004; 1007:78-85.

Morin LP. Effects of various feeding regimens and photoperiod or pinealectomy on ovulation in the hamster. Biology of Reproduction 1975; 13:99-103.

Food

Sex

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Energy Balance and Reproduction - Lehigh University · 2011. 10. 3. · Recommended Publications Klingerman CM, Krishnamoorthy K, Patel K, Spiro AB, Struby C, Patel A, Schneider JE