|dc.description.abstract||This thesis reports the effects in vivo of the sympathetic nervous system (SNS) in
human subcutaneous abdominal white adipose tissue (WAT) and other tissues
involved in energy storage and utilisation.
Cannulation of superficial veins draining skin, abdominal subcutaneous WAT and
deep forearm muscle combined with isotope turnover methodology and tissue
blood flow estimation was used to investigate the behaviour of these tissues under
varying experimental conditions.
Glucose infusion study:
This examined differential substrate uptake and utilisation in the three tissues.
WAT was responsible for only a small amount of glucose disposal and deep
forearm muscle took up but did not release NEFA. Skin was a net exporter of
lactate. Results confirm the relative purity of the venous effluent from these
Sympathetic Nervous System study:
This examined whole body, WAT and forearm muscle SNS activity in lean and
obese individuals under fasting and postprandial conditions. Whereas whole body
SNS activity was increased in the obese, regional heterogeneity of SNS activity
was evidenced by reduced SNS activity in WAT. Adipose tissue blood flow was
significantly reduced in the obese. This may underlie abnormal lipolysis and/or
blood flow regulation in obesity.
These studies examined whether lipolysis and leptin production in human WAT is
uniform or pulsatile. Novel control datasets were used to test the robustness of a
widely used pulse detection algorithm. Whereas NEFA release appeared truly
pulsatile, apparent leptin ‘pulses’ occurred with similar frequency in the control
datasets and appear likely simply to reflect variability.
Confocal immuno-fluorescence microscopy was used to demonstrate innervation
of WAT in man for the first time. Such innervation appears confined to the
microvasculature and suggests that the defective SNS activity within WAT is
likely to affect adipose tissue biology primarily through defective regulation of
adipose tissue blood flow.||en_US
|dc.title||Studies of adipose tissue in humans with special reference to innervation by the sympathetic nervous system||en_US
|dc.rights.holder||The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the author||