Different energy metabolite pattern between uterine smooth muscle and striated rectus muscle in term pregnant women.

OBJECTIVE

To study the energy metabolite pattern in term pregnant myometrium and to compare it with that of a striated skeletal muscle.

STUDY

DESIGN

Metabolites of carbohydrates, triglycerides and nucleotides were determined in biopsies from myometrium and rectus abdominis muscle from ten healthy term pregnant women before onset of labour. The metabolite concentrations in the two types of muscle were compared by two tailed Student's t-test for paired values and correlations were calculated by Pearsson's correlation test.

RESULTS

Comparison of the two muscle types revealed a higher concentration of glucose and a higher lactate/pyruvate ratio in the myometrium but a lower concentration of triglyceride metabolites. Adenosine was found in 36-fold higher concentration in the uterine compared with the rectus muscle and an inverse relationship between adenosine and glucose concentrations was observed in the myometrium.

CONCLUSION

The results indicated that the pregnant uterine smooth muscle utilized glucose as the principal nutritive metabolite rather than lipids and that the anaerobic pathway of the glucose metabolism was more active in the myometrium compared with the striated rectus muscle. Also, it is suggested that glucose has a critical role as the principal fuel for ATP formation and the involvement of the adenylate kinase and 5'-nucleotidase reactions in any event of glucose shortage.