Polyamine biosynthetic decarboxylase activities following estradiol-17 beta or estriol stimulation of the immature rat uterus.
Following a single intraperitoneal injection of 0.5 microgram estradiol-17 beta (E2) into immature female rats uterine ornithine decarboxylase (ODC) activity increased to a peak at 4 hours postinjection. It decreased to intermediate levels by 6 hours and remained elevated until returning to control levels by 18 hours. When either 0.5 microgram estriol (E3) or 0.05 microgram E2 was injected, activity increased to a 4 hour ODC peak then decreased to control levels by 10 hours. The decrease to intermediate levels of ODC activity after dosing with 0.5 microgram E2 occurred at the same time activity decreased to control levels following treatment with either 0.05 microgram E2 or 0.5 micrograms E3. S-Adenosyl methionine decarboxylase (SAMDC) activity had increased by 4 hours following an injection of 0.5 microgram E2 and remained elevated until 16 hours then decreased to control levels. An injection of 0.05 microgram E3 stimulated only a 4 hour peak after which time SAMDC decreased to control levels by 14 hours. After an injection of 5.0 microgram E2 SAMDC activity had increased by 4 hours and remained elevated for the remainder of the experiment (16 hours). Decreases in ODC activity following 4 and 10 hours may reflect a decrease in nuclear estrogen receptor levels. The ODC activity seen here following 0.5 microgram E2 injection is similar in timing to that seen in other proliferating systems and may be due to a common mechanism.
D012437:Adenosylmethionine Decarboxylase / Q000378:metabolism*; D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D004964:Estriol / Q000494:pharmacology*; D005260:Female; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014599:Uterus / Q000187:drug effects / Q000201:enzymology*
D004958:Estradiol; D002262:Carboxy-Lyases; D009955:Ornithine Decarboxylase; D012437:Adenosylmethionine Decarboxylase; D004964:Estriol