Effect of aging on growth hormone-leptin axis in normal andobese healthy subjects


Background: Growth hormone is a hormone responsible for the normal body
growth and development by stimulation protein production in muscle cells and
energy release for breakdown of fat. On the other hand leptin is a newly discovered
hormone that is mainly synthesized in adipose tissues it decreases food intake by
causing satiety and promoting energy combustion . Both aging and obesity are
associated with a reduction in growth hormone secretion. In the mean time obese
humans have increased circulating leptin.
Objective: The aim of this paper is to shed light on the contribution of these two
hormones in the mechanism of aging process in an attempt of improving this
process for a better life at old ages.
Subjects and methods: Two hundred and seventy healthy subjects aged 25-64
years old participated in this study. The subjects' were divided into four groups
according to their ages and to three groups according to their weights. Urine
analysis from each subject was carried out to exclude diabetes and renal failure.
Sera from blood samples were used to carry out certain biochemical parameters and
hormone (growth hormone and leptin).
Results: The results obtained show a decrease in the level of growth hormone with
progression of age. In the mean time there is an increase in the level of serum leptin
with the advancement of age. Aging is usually associated with adiposity. Increasing
fat with age is probably multifactorial one potential mechanism for that is reduced
leptin transport across blood-brain barrier..
Conclusion: The increase in leptin level which was observed in elderly age group
and obese group suggest that the associated decrease in growth hormone serum
level is related to obesity in general and in particular to the aging process.