ADAPTATIONS TO GH/INSULIN BALANCE: AN ESSENTIAL PHYSIOLOGICAL RESPONSE TO SUSTAIN NEFA FLUX FOLLOWING DIETARY INDUCED WEIGHT GAIN

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 685-694-Mechanisms of Obesity
Basic
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-694
Frederik Jacobus Steyn*1, Teresa Xie1, Lili Huang1, Shyuan Ngo1, Johannes D Veldhuis2, Michael John Waters3 and Chen Chen1
1The University of Queensland, Australia, 2Mayo Clinic, Rochester, MN, 3Univ of Queensland, Brisbane QLD, Australia
Clinical observations highlight the physiological role of growth hormone (GH) in modulating insulin-induced lipogenesis throughout periods of positive energy balance. It is thought that impaired GH secretion relative to dietary induced weight gain contributes to improved meal tolerance, insulin responsiveness, and consequently the maintenance of nonesterified free fatty acid (NEFA) flux. Thus, we anticipate that alterations in GH/insulin balance represent an essential physiological adaptation to prevent dyslipidemia.

To clarify the association between adiposity and GH secretion, we investigated the relationship between pulsatile GH secretion and body weight, epididymal fat mass, circulating levels of insulin, and non-esterified free fatty acids (NEFAs). Data were obtained from male mice maintained on a standard or high fat diet. We confirm the suppression of pulsatile GH secretion following dietary induced weight gain. Correlation analyses reveals an inverse relationship between measures of pulsatile GH secretion, body weight and epididymal fat mass. We demonstrate an inverse relationship between parameters of pulsatile GH secretion and circulating levels of insulin. The secretion of GH does not change relative to circulating levels of NEFAs.

We conclude that impaired pulsatile GH secretion in the mouse occurs alongside progressive weight gain, and thus precedes the development of obesity. The close inverse relationship between circulating levels of insulin and pulsatile measures of GH secretion suggest a complementary role in sustaining balanced NEFA flux. Using transgenic and dietary induced obese mouse models, we are now investigating the role of altered GH/Insulin balance in progressive weight gain, obesity and related pathologies.

Nothing to Disclose: FJS, TX, LH, SN, JDV, MJW, CC

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

<< Previous Abstract | Next Abstract