The Hong Kong Journal of Sports Medicine and Sports

Volume XV, November 2002

The Effects of Exogenous Growth Hormone Administration on Aorta, Renal, Hepatic Orphology and Serum Lipid Metabolism in Exercised Rats

Beijing University of Physical Education, Beijing, China

China National Research Institute of Sports Medicine, China

Specifically designed program of endurance training plus exogenous growth hormone administration were used to determine the effects or side-effects of rhGH on aorta, renal, hepatic morphology and serum lipid metabolism in both exercise and control rats. 28 adult health SD rats were randomly divided into four groups i.e. control group (n=8), injection group (n=6), exercise group (n=8), exercise plus injection group (n=6). After one week of adaptation, the exercise and exercise plus injection groups were trained by treadmill (5% grade and 20m/min, 1 hr/day, 6d/week for 8 weeks). After 4 weeks of training, rhGH was given in a double-blinded, placebo-controlled design to injection and exercise plus injection groups. rhGH was injected subcutaneously with the dose of 2.5-3mg/kg/day, at 8 p.m. everyday for 4 weeks. Samples were collected after the last injection and a 12-hour fast. Results: After 4 weeks of injection and 8 weeks of exercise, there were some pathological changes on aorta from morphological observation. In control and injection groups, there was disorder in internal elastic membrane in all samples. Elastic fibers were found partially ruptured, while vascular smooth muscle hyperplasia occurred in 2/3 samples. In the exercise group, there were ruptures in the internal elastic membrane partly. Elastic fiber increased but there were no ruptures observed. In exercise plus injection group, there was low-grade hyperplasia in vascular smooth muscle, and only one was found with elastic fibers ruptured. In injection and exercise plus injection group, there was some cloudy swelling in the renal proximal tubules. The cavity of the tubules is unclear, and has a little turbid liquid. There were no pathological changes in the other two groups. As for the hepatic cells, fatty degeneration was observed in both exercise plus injection group and in control group, and the exercise plus injection group was more severely affected than the injection group. In the dose administered, in compared with the control group, there were significant increases in total cholesterol level (TC)(p<0.01), high-density lipoprotein cholesterol (HDL) level (p<0.01), and low-density lipoprotein cholesterol (LDL) (p<0.05) in the injection group. In exercise plus injection group, there were significant increases in TC (p<0.05) and LDL (p<0.05) level, and significant decreases in TG (p<0.01) level. There was no obvious changes in the exercise group. Conclusion: The effects of long-term administration of rhGH on rats are: (1) Having adversed effects on aorta morphology, causing partial rupture in aorta elastic fibre and increasing the tendency of arteriosclerosis. (2) Leading to pathological damages in liver and kidney and (3) Inducing the turbulence of lipoprotein metabolism.

Key Words: Pathological effects, rhGH, training.

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