HIGH ADENOSINE CONTENT IN HUMAN UTERINE SMOOTH-MUSCLE COMPARED WITH STRIATED SKELETAL-MUSCLE

We determined the concentrations of adenosine and some of its cataboli c products in biopsy specimens from predetermined loci of human myomet rium under different functional conditions to compare uterine muscle w ith rectus abdominis muscle from the same individuals. In order to ach ieve a good resolution in the separation of nucleosides and purine bas es, a preseparation procedure was developed prior to analysis of these compounds on high performance liquid chromatography. Adenosine occurr ed in a nearly 70-fold higher concentration in smooth uterine muscle i n comparison with striated skeletal muscle. Similarly, myometrial inos ine and hypoxanthine were 7- and 2.4-times in excess over the rectus m uscle, whereas xanthine was scarcely and rather evenly represented in the two types of muscles. The uterine content of adenosine and inosine was distinctly higher in pregnant women compared to non-pregnant ones . A regional difference existed for adenosine, with 3.3 times higher c oncentration in fundus uteri compared to the isthmic part. A reverse p attern was observed for hypoxanthine and inosine, being 2-3 times more frequent in the isthmic part. The orthophosphate concentration was no t stoichiometrically related to the adenosine concentration in a simpl e way, being 2-3 times lower in uterine muscle compared to the skeleta l muscle. A significant correlation existed between uterine contents o f AMP and adenosine and similarly, significant inverse correlations we re apparent between uterine ATP and ADP contents and energy charge on one hand and adenosine content on the other.