Adenosine receptor mRNA levels during postnatal renal maturation in the rat.

Adenosine may affect the pattern of intrarenal blood flow during renal development. It provides an angiogenic stimulus for the growth of new blood vessels and may be involved in compensatory renal growth. It is therefore of interest to investigate the expression of adenosine receptor genes during postnatal renal development. In the present study this was carried out by measuring 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 A2A > A2B > or = A1 > A3. A1 receptor mRNA levels showed only small changes with increasing age although, by contrast, A3 receptor mRNA increased markedly with age with levels at 60 days twenty-fold greater than at 2 days. A2A receptor mRNA levels declined during renal maturation with transcript numbers four- to fivefold that at 12-18 days compared with numbers at 60 days. By contrast to the A2A receptor, there were no significant changes in the renal levels of A2B receptor mRNA during kidney maturation. During postnatal renal maturation, the levels of mRNA for A2A and A3 adenosine receptor subtypes undergo marked changes which may be related to functional maturation, morphological development, or both.