Adenosine receptor mRNA levels during postnatal renal maturation in the rat

Adenosine may affect the pattern of intrarenal blood flow during renal deve lopment. It provides an angiogenic stimulus for the growth of new blood ves sels and may be involved in compensatory renal growth. It is therefore of i nterest to investigate the expression of adenosine receptor genes during po stnatal renal development. In the present study this was carried out by mea suring adenosine receptor mRNA levels in rats aged between 2 and 60 days. The order of abundance of adenosine receptor mRNA levels in 60-day-old rats was A(2A) > A(2B) greater than or equal to A(1) >A(3). A(1) receptor mRNA levels showed only small changes with increasing age although, by contrast, A(3) receptor mRNA increased markedly with age with levels at 60 days twen ty-fold greater than at 2 days. A(2A) receptor mRNA levels declined during renal maturation with transcript numbers four- to fivefold that at 12-18 da ys compared with numbers at 60 days. By contrast to the A(2A) receptor, the re were no significant changes in the renal levels of A(2B) receptor mRNA d uring kidney maturation. During postnatal renal maturation, the levels of mRNA for A(2A) and A(3) ad enosine receptor subtypes undergo marked changes which may be related to fu nctional maturation, morphological development, or both.