OBJECTIVETo observe changes of plasma polypeptide hormone levels in rats with gastric ulcer after exposure to intense noise, and to discuss their mechanism.

METHODS80 Wistar rats were used in the study. Plasma levels of rat gastrin (GAS), motilin (MTL), osteocalcin (BGP), substance P (SP), neurotensin (NT) and somatostatin (SS) in rats were measured by radioimmunoassay.

RESULTS(1) In non-noise-exposure but with gastric ulcer group, the plasma MTL [(160.70 +/- 40.34) pg/ml] and BGP [(27.63 +/- 13.13) pg/ml] levels on 10 d after gastric ulcer model operation were remarkably higher than those in control group [(89.21 +/- 49.94) pg/ml, (9.10 +/- 1.38) pg/ml respectively] (P < 0.05 and P < 0.01), while the GAS level was remarkably descended [(107.00 +/- 21.75) vs (158.48 +/- 20.92) pg/ml] (P < 0.01). (2) In noise-exposure but without gastric ulcer group, the plasma MTL [(312.80 +/- 207.42) pg/ml] and BGP [(17.76 +/- 12.33) pg/ml] levels on 10 d were also significantly increased as compared with the control group (P < 0.01 and P < 0.05 respectively), while the GAS levels didn't change. (3) In noise-exposure + gastric ulcer group, the areas of gastric ulcer on 10 d and 40 d after noise and operation [(15.33 +/- 7.26) and (15.11 +/- 12.45) mm(2) respectively] were significantly larger than those of the control [(8.22 +/- 6.66), (3.67 +/- 9.90) mm(2)] (P < 0.05). The plasma MTL levels on 10 d and 40 d [(244.44 +/- 68.11) and (191.20 +/- 60.50) pg/ml respectively] were higher than those in control group [(160.70 +/- 40.34) and (93.10 +/- 52.90) pg/ml respectively] (P < 0.01).

CONCLUSIONIntense noise exposure may make the rat gastric ulcer worsened and induce negative effect on healing of it. The gastrointestinal endocrine would be disturbed by combined effect of intense noise exposure with gastric ulcer in rats.