Effects of leptin on adipose tissue metabolism in male C57Bl/6 mice and Sprague Dawley rats
Rooks, Cherie Renee
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Leptin decreases body weight by decreasing fat stores and preserving lean tissue. Although much is known about leptin, there are mechanisms of leptin function yet to be determined. The objective of this thesis was to determine the importance of sympathetic innervation of white adipose tissue in mediating the effects of leptin on fat. Male C57Bl/6 mice and Sprague Dawley rats that were unilaterally denervated and infused with leptin showed that the sympathetic nervous system (SNS) is not necessary for leptin induced decreases on body fat in mice. In rats, however, the SNS is necessary for leptin action, of one pad but denervation also increases the sensitivity of distant fat depots to leptin. Changes in fat metabolism due to leptin were not clearly determined. Surprisingly, removal of the SNS in one pad resulted in an increased response of the contralateral pad to insulin and norepinephrine. These studies imply that the SNS may not be necessary for all leptin-induced responses of adipose tissue; however, this is not consistent in all species and still needs further investigation.