Leptin and energy balance: exploring Leptin’s role in the regulation of energy intake and energy expenditure

ABSTRACT

Leptin is a tonic appetite-regulating hormone, which is integral for the long-term regulation of energy balance. The current evidence suggests that the typical orexigenic or anorexigenic response of many of these appetite-regulating hormones, most notably ghrelin and cholecystokinin (CCK), require leptin to function whereas glucagon-like peptide-1 (GLP-1) is required for leptin to function, and these responses are altered when leptin injection or gene therapy is administered in combination with these same hormones or respective agonists. The appetite-regulatory pathway is complex, thus peptide tyrosine tyrosine (PYY), brain-derived neurotrophic factor (BDNF), orexin-A (OXA), and amylin also maintain ties to leptin, however these are less well understood. While reviews to date have focused on the existing relationships between leptin and the various neuropeptide modulators of appetite within the central nervous system (CNS) or it’s role in thermogenesis, no review paper has synthesised the information regarding the interactions between appetite-regulating hormones and how leptin as a chronic regulator of energy balance can influence the acute appetite-regulatory response. Current evidence suggests that potential relationships exist between leptin and the circulating peripheral appetite hormones ghrelin, GLP-1, CCK, OXA and amylin to exhibit either synergistic or opposing effects on appetite inhibition. Though more research is warranted, leptin appears to be integral in both energy intake and energy expenditure. More specifically, functional leptin receptors appear to play an essential role in these processes.

KEYWORDS:

• Obesity
• Ghrelin
• GLP-1
• CCK
• Appetite hormones
• appetite regulation
• leptin receptors
• gastrointestinal hormones

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data sharing is not applicable to this article has no new data were created or analysed in this study.

Additional information

Notes on contributors

Jessica A.L. Tucker

Jessica A.L. Tucker was an MSc student interested in the role of ovarian hormones in appetite regulation.

Derek P.D. Bornath

Derek P.D. Bornath is currently a PhD candidate interested in the potential role of blood glucose in appetite regulation.

Seth F. McCarthy

Seth F. McCarthy is currently a PhD Candidate interested in the role of lactate in appetite regulation.

Tom J. Hazell

Tom J. Hazell (PhD) is an Associate Professor who studies the potential mechanisms involved in how exercise affects appetite regulation.