-We studied the contractile activity and glucose metabolism, in terms of production of 14 CO 2 from [ 14 C] glucose, in isolated uteri of immature rats. Immaturity was due to age or exposure to a restricted diet. The contractile activity in both prepubertal groups persisted for a period of 60 minutes and fell when indomethacin was added to the KRB medium. The production of 14 CO 2 was greater than for adult rats and fell as a result of the addition of indomethacin. The metabolism of [ 14 C] arachidonic acid showed that the percentage of eicosanoids released in age related immature uteri was greater than that in restricted diet related immature uteri. In animals that are immature as a result of exposure to a restricted diet, 14 CO 2 fell due to the effect of NAME. Sodium nitroprusside and L-arginine increased the production of 14 CO 2 . This effect was reverted by NAME and indomethacin. Conversely, the uteri of age related prepubertal rats were not affected. The level of activity of nitric oxide synthase was higher in restricted diet related immature animals and fell following the addition of NS-398. We may conclude that in rats exposed to a restricted diet, NO and COX-2 participate in glucose metabolism whereas they would not be involved in age related prepubertal animals.immature rats / glucose metabolism / nitric oxide / arachidonic acid