Previous studies have provided evidence that several key elements of renin-angiotensin system (RAS) are present in the rat pancreas, notably
angiotensinogen, which is mandatory for intracellular generation of physiologically active
angiotensin II. The data support the existence of an intrinsic RAS, which may be important for pancreatic blood flow and ductal
anion secretion. In the present study, the effect of chronic
hypoxia on the expression of RAS components, particularly at the levels of its precursor
angiotensinogen and its receptor subtypes AT(1) and AT(2), were investigated in the rat pancreas. Results from western blot and semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) analyses unequivocally showed that chronic
hypoxia caused a marked increase in
angiotensinogen both at the
protein and gene levels when compared with that in the normoxic pancreas. However, results from RT-PCR showed that there was a differential effect of chronic
hypoxia on the expression of AT(1) and AT(2) receptor subtypes, which exhibited subtype-specific changes in gene expression. For AT(1), chronic
hypoxia did not cause a significant change in
mRNA expression for AT(1a) but a significant increase in
mRNA expression for AT(1b). For AT(2), chronic
hypoxia caused a marked increase in its
mRNA expression. The increased expression of RAS component genes by chronic
hypoxia and its significance of changes may be important for physiological and pathophysiological aspects of the pancreas.