An investigation of the effect of short bouts of exercise on adiponectin concentrations in young healthy females

Alzwayi, Mabroukah MA (2013) An investigation of the effect of short bouts of exercise on adiponectin concentrations in young healthy females. PhD thesis, University of Glasgow.

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Abstract

White adipose tissue is not just a storage organ. It is now recognised as an
endocrine organ. It secretes many substances known as adipokines, which are
thought to link obesity with type 2 diabetes (T2D). One of the most important
adipokines is adiponectin. It is a peptide hormone consisting of 244 amino
acids with molecular weight of 30 KD. It circulates in plasma in high
concentrations (3-30 4g/ml). Adiponectin polymerises to form many bigger
forms. Those are low molecular weight (LMW); middle molecular weight
(MMW) and high molecular weight (HMW). The HMW adiponectin is the active
form of the hormone.
The concentrations of most adipokines are increased in obese people.
Adiponectin is unusual in that its concentration is lower in obese people.
Consequently its concentration is decreased in some related metabolic
disorders. Its concentrations decrease in cardiovascular diseases, diabetes,
dyslipidemia and insulin resistances. It is well known that exercise increases
insulin sensitivity, also adiponectin was reported to regulate insulin. The
effect of exercise on the adiponectin concentrations in plasma is
controversial, but the extent to which the exercise regulates the interstitial
adiponectin concentrations is not fully examined. The main site of adipokines
secretion is adipose tissue. Therefore the study of these substances at the
site of their production has a special interest. Recently, microdialysis
techniques have been extended to become important in the measurement of
substances in the extracellular fluid of many tissues such as subcutaneous
adipose tissue. In particular, it has been used for measurement of adipokines.
This thesis includes three studies. The first study was aimed at examining the
effect of one hour of moderate exercise at 50% of maximum oxygen
consumption v on adiponectin concentration in dialysate samples taken from
subcutaneous abdominal adipose tissues (SCAAT). 15 healthy young female
volunteers, age 22.8 ± 3.0 years (mean ± SD) participated in this experiment
divided into two groups depending on their body mass index (BMI), a lean
group BMI 22.2 ± 1.6 kg/m2 (mean ± SD) and an overweight group BMI 27.7 ±
1.9 kg/m2 (mean ± SD). The samples were collected using CMA 66
M. Alzwayi iii
microdialysis catheters with membrane cut off 100 KD. Fitness assessment
was done for all volunteers about one week before the main trials. The main
trials were done on two consecutive days, a rest day and an exercise day.
Each day lasted for 4 to 6 hours. On the first day the microdialysis catheter
were inserted in abdominal subcutaneous tissue 4 cm lateral to the umbilicus
on the left side. Dialysate samples were collected every 30 - 45 minutes. On
the exercise day volunteers exercised for one hour at 50% 2
.
V O max. All
samples were analysed for adiponectin concentrations using Mercodia ELISA
technique.
The principle findings of this study were that CMA 66 microdialysis catheters
worked effectively for two consecutive days for fluid recovery. Adiponectin
concentrations were very low and varied, in same volunteer from time to
time, and between volunteers. However, the statistical analysis showed no
significant difference in adiponectin concentrations between lean and
overweight groups. Adiponectin concentrations in the first two samples on
the first day of the insertion were significantly higher than the first two
samples on the second day of the insertion. Finally, adiponectin
concentrations in dialysate samples recovered by 100 KD microdialysis
catheters were very low. Therefore, the effect of the exercise was not clear.
The second study aimed to compare the adiponectin concentrations in plasma
and dialysate samples. Six healthy male volunteers age 32.8 ± 13.1 years and
BMI 25.9 ± 3.3 kg/m2 (mean ± SD), were recruited for this study. The
experiment was run for two consecutive days using the same microdialysis
catheters CMA 66. Dialysate samples were collected as before. 2 ml of blood
samples were collected using a cannula inserted into the anticubital vein.
Samples were taken every hour for a period of five hours each day. The
plasma and dialysate samples were analysed for adiponectin using the
Mercodia kits. Adiponectin concentrations in plasma samples were 256 and
1791 times higher than the adiponectin concentrations in dialysate samples.
The conclusion of the two studies was that the CMA 66 microdialysis catheter
with cut off 100 KD membranes only recovers a small part of the total
adiponectin present.
M. Alzwayi iv
Therefore a third study was designed to use plasma samples. The aim of the
study was to investigate the effect of acute exercise at 50% 2
.
V O max on HMW
adiponectin, total adiponectin, interleukin (IL)-6, tumour necrosis factor
alpha (TNF-α), insulin and glucose concentrations directly after the exercise,
one hour after and 48 hours. 13 young healthy female volunteers age 24.3 ±
2.7 years and BMI 21.9 ± 2.2 kg/m2 (mean ± SD) contributed in this study. The
volunteers were invited for five visits. Their fitness was measured on the first
visit. Then they came for two main trials rest day and exercise day, which
they were randomly assigned. The main trails lasted for two hours. Three
blood samples were collected each day using same cannulated system in the
second study. The volunteers followed 48 hours after each trial, one blood
sample were collected each day. The 8 plasma samples were analysed for:
total adiponectin and insulin concentrations via Mercodia ELISA kits, HMW
adiponectin, IL-6 and TNF-α concentration via R&D systems and glucose
concentration using the glucose oxidase colorimetric method.
The results showed no statistical difference in total or HMW adiponectin,
TNF-α and glucose concentrations under the effect of moderate exercise at
50% 2
.
V O max either directly or 48 (p value > 0.05). IL-6 concentrations
increased about two fold one hour after the exercise above the resting level
(P value < 0.05). IL-6 concentrations return to the basal level 48 hour latter.
Insulin concentrations show a decrease one hour after the exercise finished.
The number of volunteers was small and the change was close to significance.
A one way ANOVA returned a P value of < 0.05, but a two way ANOVA with
repeated measures returned a P value of > 0.05.
In conclusion, the acute exercise at 50% 2
.
V O max changes IL-6 concentrations
but it has no effect on adiponectin concentrations in dialysate or plasma
samples. Low adiponectin concentration is related to obesity, insulin
resistance and T2D. Therefore, increase in adiponectin concentration
probably lies in weight loss and the exercise may play role, even if it has
little direct action on adiponectin concentration.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Adiponectin, women, exercise, adipose tissues
Subjects: A General Works > AI Indexes (General)
Q Science > Q Science (General)
Q Science > QP Physiology
R Medicine > R Medicine (General)
Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Life Sciences > Life Sciences Human Biology/Sports Science
Supervisor's Name: Baxendale, Dr. Ronald H.
Date of Award: 2013
Depositing User: Mrs Mabroukah M. A. Alzwayi
Unique ID: glathesis:2013-4552
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 02 Sep 2013 13:09
Last Modified: 23 Mar 2015 08:29
URI: http://theses.gla.ac.uk/id/eprint/4552

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