Many peptide precursors encode more than one bioactive peptide. Recent cloning of the rat neuromedin U (NmU) precursor revealed potential proteolytic processing sites which may generate three associated peptides in addition to the NmU peptide, which is known to have potent uterine contractile effects. To assess the degree of evolutionary conservation, which often suggests conserved biological function and hence physiological importance, we have cloned and sequenced the cDNA encoding the human NmU precursor. Sequence analysis revealed a 174 amino acid human precursor containing the 25 residue NmU peptide near the C terminus of the precursor. The human message sequence was 74% homologous with that of the rat, indicating evolutionary conservation of the precursor between these two species. Four out of five of the putative proteolytic processing sites, first revealed in the rat precursor, were conserved in the human precursor, indicating a similar processing mechanism in both species. Two such processing sites flank a 33 residue peptide sequence which differed in only two amino acids compared with the rat homologue. This conservation suggests a possible biological role for this putative peptide. Northern blot analysis of human gastrointestinal tissues revealed a similar level of mRNA throughout the gastrointestinal tract. RIA using a porcine specific assay showed the highest levels of peptide in the jejunum samples.

The responses of nine men and nine women to brief repetitive maximal exercise have been studied. The exercise involved a 6-s sprint on a non-motorised treadmill repeated 10 times with 30 s recovery between each sprint. The total work done during the ten sprints was 37,693 +/- 3,956 J by the men and 26,555 +/- 4,589 J by the women (M greater than F, P less than 0.01). This difference in performance was not associated with higher blood lactate concentrations in the men (13.96 +/- 1.70 mmol.l-1) than the women (13.09 +/- 3.04 mmol.l-1). An 18-fold increase in plasma adrenaline (AD) occurred with the peak concentration observed after five sprints. The peak AD concentration in the men was larger than that seen in the women (9.2 +/- 7.3 and 3.7 +/- 2.4 nmol.l-1 respectively, P less than 0.05). The maximum noradrenaline (NA) concentration occurred after ten sprints in the men (31.6 +/- 10.9 nmol.l-1) and after five sprints in the women (27.4 +/- 20.8 nmol.l-1). Plasma cardiodilatin (CDN) and atrial natriuretic peptide (ANP) concentrations were elevated in response to the exercise. The peak ANP concentration occurred immediately post-exercise and the response of the women (10.8 +/- 4.5 pmol.l-1) was greater than that of the men (5.1 +/- 2.6 pmol.l-1, P less than 0.05). The peak CDN concentrations were 163 +/- 61 pmol.l-1 for the women and 135 +/- 61 pmol.l-1 for the men. No increases in calcitonin gene related peptide (CGRP) were detected in response to the exercise. These results indicate differences between men and women in performance and hormonal responses. There was no evidence for a role of CGRP in the control of the cardiovascular system after brief intermittent maximal exercise.

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1. Atrial natriuretic peptide (ANP) levels were measured in cardiac tissues and in plasma from adult rats exposed to chronic alveolar hypoxia for periods of 2 h, 24 h and 7 days. Levels were also measured in rats that were maintained in hypoxia for 7 days and then returned to air for 24 h. 2. Plasma ANP was not altered at 2 h but was significantly increased at both 24 h and at 7 days. Plasma ANP in animals exposed to hypoxia for 7 days was normal 24 h after returning to air breathing, despite the persistence of indices of pulmonary hypertension. 3. No significant right atrial hypertrophy was observed under these conditions of chronic hypoxia. A reduction in right atrial ANP content was found at 24 h and was accompanied by a decrease in the number of electrondense granules per right atrial muscle cell. After exposure to hypoxia for 7 days, right atrial ANP and granule number was not different from control, and no alteration was found in right atrial ANP level after removal from the hypoxic environment. 4. No significant right ventricular hypertrophy was produced by exposure to hypoxia for 2 or 24 h. In the former group ventricular ANP had decreased significantly compared with control. Right ventricular hypertrophy was found in both the hypoxic groups after exposure for 7 days, when selective increases in right ventricular ANP content were found. 5. These findings are consistent with the hypothesis that ANP release occurs on exposure to chronic hypoxia and is independent of the associated cardiac hypertrophy and pulmonary vascular remodelling. The findings may have relevance to the natriuresis and reported changes in the renin-angiotensin-aldosterone axis under hypoxic conditions.

INTRODUCTION The aim of this study was to conduct retrospective analysis of abdominopelvic computed tomography (CT) reports, identifying those patients in whom bowel wall thickening (BWT) was observed, and to correlate these reports with subsequent endoscopic evaluation. METHODS Formal reports for all patients undergoing abdominopelvic CT between February 2007 and September 2009 were reviewed. Where patients were identified as having colorectal 'wall thickening', results of subsequent endoscopic evaluations were documented. Only those patients with a report of BWT who had follow-up endoscopy (colonoscopy, sigmoidoscopy) were included in the analysis. RESULTS A total of 165 patients were included. Abnormalities on endoscopy at the exact site of the BWT on CT were found in 95 patients (57.58%); in 36 cases (21.82%) this was a malignant lesion. BWT of the transverse colon was significantly more likely to correspond to an endoscopic finding of cancer than other sites (p=0.034). Rectal bleeding was reported significantly more often in patients with BWT and neoplastic disease on endoscopy compared with those with normal endoscopy (p=0.04). Excluding patients with inflammatory/diverticular lesions, 59.02% of Caucasians had a neoplastic lesion at the site of reported BWT, significantly higher than the other ethnic groups (p=0.008). There were 38 patients (23.03%) who did not present with bowel symptoms and, of these, 6 were diagnosed subsequently with colorectal cancer. CONCLUSIONS This study supports endoscopic evaluation to investigate patients with CT evidence of BWT, especially in cases involving the transverse colon, in Caucasian patients or in association with symptoms of rectal bleeding.