Guan Wei
1
, Hua Mao
1
, Pang Guo-Yi
2
, Mao Hui-Qing
3
. Dept. of the Respiratory, Affiliated
hospital of Qinghai Medical College, Xining, Qinghai, P. R. Ch
1
, The department of Medicine of
Qinghai Military Region
2
, Qinghai Medical College
3
.
To study effects of Calcitonin gene-related peptide(CGRP), Endothelin(ET), C-type
natriuretic(CNP),,Neurotensin (NT), and NeuropeptideY (NPY) on physiological regulation of
pulmonary circulation and to probe the role of the lung in metabolism of these active
polypeptides in lower altitude healthy volunteers at high altitude. Methods: Volunteers were
randomly divided into control group(residing at 1100m,CG) and hypoxic group[traveling to
2260m,(MA) and at 3780m at 1d(H1d), 5d (H5d) and 15d(H15d)]. Arterial (A) and venous (V)
blood samples were collected and were measured by radioimmunoassay. Results: 1.Analysis of
variance: _ ET The plasma ET content of A and V in H5d was significantly decreased (the
content of A compared with CG, MA and H1d. p<0.01). In H15d the content of V increased
significantly compared with the content of V in MA, H1d, H5d and that of A in H15d (p<0.01).
CGRP CGRP in plasma of A and V in MA had reached peak (compared with CG p<0.01), then
they continuously dropped with increase of altitude and prolongation of time in hypoxia. The
differences were significant in H15d compared with CG, MA, H1d and H5d (p<0.01). CNP CNP
of A and V were significantly increased with increased altitude and prolonged time at high
altitude. CNP was remarkably higher in H15d than in CG, MA, H1d and H5d. (p<0.01). .NT The
A contents of NT reached a peak in H5d (compared with CG, MA and H1d p<0.01) and the V NT
was the highest in H15d (compared with MA, H1d and H5d p<0.01). 2. t- test between A and V
each group: There were significant differences between A and V of ET and CGRP in H15d and
NT in CG and H5d.3.Rectification correlation analysis: CGRP V plasma content versus CNP and
ET V plasma content showed negative correlation and NT versus NPY showed a positive
correlation P <0.05 and 0.01. CGRP A plasma content versus ET showed negative correlation
P<0.05 in H15d. Conclusion: 1There is a reaction of the human body to hypoxia at an altitude of
2260m. 2. At 2260m and at 3760m, the dilation of blood vessels was the essential reaction of
pulmonary circulation to hypoxia. With prolonged hypoxic time and increased altitude, the
content of CGRP and NT decreased quickly, the ET content increased significantly, and the
pulmonary vessels contracted. 3. There is a correlation between injury of the endothelial cell of
pulmonary vessel caused as a result of hypoxia and a decrease in the amounts of several active
polypeptides in H1d4. The lungs had an effect on the metabolism of CGRP ET and NT.
46.
COMPARATIVE STUDY ON NITRIC OXIDE AND ENDOTHELIN-1 IN RATS AND PIKAS
AT HIGH ALTITUDE. Liu Feng-yuan, Wang Xiao-Qing, Chen Qiu-Hong, Wang Zhi-Gang.
Qinghai High Altitude Medical Institute, Xining, China.
Endothelin-1 (ET-1) and nitric oxide (NO) have recently been implicated in blood vessel
contraction and dilation. Both of them play important roles in maintaining pulmonary artery
pressure. The aim of present study was to compare NO_ET-1 and NO/ET-1 in Wistar rats and
plateau pikas. We determined NO and ET-1 levels in the serum of 30 rats (three groups of 10 rats,
each taken to 3780m, divided into 24h, 2wk and 3wk duration, respectively) and 10 pikas at
3780m by ELISA and Nitrate Reductase Method. We compared the values of NO, ET-1 and
NO/ET-1 in rats of 24h with those in rats of 2wks, 3wks. We then compared NO, ET-1 and
NO/ET-1 values in the 24h, 2wk, 3wk groups with those in pikas. In the beginning of entry to
high altitude the NO and ET-1 levels in rats were obviously increased compared to those in pikas
(mean, 47.03 vs. 36.52 umol/l, 1.24 vs. 1.07 pg/ml, respectively, p<0.01), whereas the values of
NO/ET-1 in rats and pikas were very close (37.77 vs.34.24, p0.05). There was a decreasing trend
in NO (47.03, 23.04, 20.9, p<0.01)and an increasing trend in ET-1 (1.24, 1.35, 1.34, p<0.01) with
passage of time at high altitude in rats, and the NO was well correlated with ET-1 (r=0.243,
p<0.01). The NO/ET-1 levels in pikas were approximately 2 fold greater than in the 2wk and 3wk
groups ( p<0.01). In conclusion, an appropriate ratio of NO/ET-1 in pikas plays an important role
in adaptation to high altitude hypoxia. Whereas early at high altitude the great increase of NO and
NO/ET-1 could be a useful compensatory mechanism resisting pulmonary artery hypertension,
