The influence of chronic intermittent hypoxia on hypothalamic-somatotropic axis in rats / 中华内科杂志

ABSTRACT

Objective To investigate the effects of chronic intermittent hypoxia on somatotropic axis hormone levels in rats.Methods Mature male Wistar rats were exposed to air or intermittent hypoxia randomly.The serum levels of growth hormone-releasing hormone (GHRH),growth hormone (GH) and somatostatin (SS) were measured before exposure,at the 4th,8th,and 12th week after exposure.Different hormone levels in two groups were compared and analyzed.Results Compared with the control group,GHRH levels in chronic intermittent hypoxic group showed a significant decline at the 4th week [(732.77± 46.99)pg/ml vs.(893.59±40.00) pg/ml,P＜0.05],while SS levels at the 8th week [(30.71 ±2.27) pg/ml vs.(44.69±3.36) pg/ml,P＜0.05] and GH levels at the 12th week [(1.20±0.29) ng/ml vs.(2.06±0.13) ng/ml,P＜0.05]were similarly reduced.As the duration of intermittent hypoxia was prolonged,the GHRH levels did not decrease further [4th week (732.77±46.99) pg/ml vs.8th week (607.54± 131.61) pg/ml vs.12th week (730.05±40.63) pg/ml,P＞0.05].However,the serum SS levels decreased further from the 8th week to the 12th week [(30.71±2.27) pg/ml vs.(24.41±4.06) pg/ml,P＜0.05].Conclusion Chronic intermittent hypoxia might inhibit the function of somatotropic axis.Hypothalamic hormones are the earlyonesto be influenced,thereafter the entire axis.