Effects of central or peripheral leptin administration on norepinephrine turnover in defined fat depots

Dawn M. Penn, Lisa C. Jordan, Emily W. Kelso, Jessica E. Davenport, Ruth B.S. Harris

Research output: Contribution to journalArticlepeer-review

52 Scopus citations

Abstract

Leptin preserves lean tissue but decreases adipose tissue by increasing lipolysis and/or inhibiting lipogenesis. The sympathetic nervous system (SNS) is a primary regulator of lipolysis, but it is not known if leptin increases norepinephrine turnover (NETO) in white adipose tissue. In this study, we examined the effect of leptin administered either as a chronic physiological dose (40 μg/day for 4 days from ip miniosmotic pumps) or as an acute injection in the third ventricle (1.5 μg injected two times daily for 2 days) on NETO and the size of brown and white fat depots in male Sprague Dawley rats. NETO was determined from the decline in tissue norepinephrine (NE) during 4 h following administration of the NE synthesis inhibitor α-methyl- paratryrosine. The centrally injected leptin-treated animals demonstrated more dramatic reductions in food intake, body weight, and fat pad size and an increase in NETO compared with the peripherally infused animals. Neither route of leptin administration caused a uniform increase in NETO across all fat pads tested, and in both treatment conditions leptin decreased the size of certain fat pads independent of an increase in NETO. Similar discrepancies in white fat NETO were found for rats pair fed to leptin-treated animals. These results demonstrate that leptin acting either centrally or peripherally selectively increases sympathetic outflow to white fat depots and that a leptin-induced change in fat pad weight does not require an increase in NETO.

Original languageEnglish (US)
Pages (from-to)R1613-R1621
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume291
Issue number6
DOIs
StatePublished - 2006
Externally publishedYes

Keywords

  • Brown adipose tissue
  • Sympathetic nervous system
  • White adipose tissue

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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