Influence of morphinization on the development of isoenzymes of pyruvate kinase in rat liver.
1. Acute administration or morphine to foetuses and neonates either directly or via the mother leads to a decrease in the total pyruvate kinase activity. 2. The L-type isoenzyme is selectively suppressed while the M-type isoenzyme is not altered to any significant extent with a consequent lowering of the L/M ratio. 3. The decrease in the total pyruvate kinase activity and the L/M ratio is more prominent when the route of administration of morphine is via the mother. 4. The possible explanation for this difference in the route of administration is that morphine can be converted into a more active metabolite with greater biological potency in adult animals.
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D005260:Female; D007527:Isoenzymes / Q000378:metabolism; D008099:Liver / Q000196:embryology / Q000201:enzymology*; D009020:Morphine / Q000494:pharmacology*; D011247:Pregnancy; D011770:Pyruvate Kinase / Q000378:metabolism*; D051381:Rats; D013997:Time Factors
D007527:Isoenzymes; D009020:Morphine; D011770:Pyruvate Kinase