title: Uterine and kidney aspartate aminotransferase activity in ethinylestradiol- and norgestrel-treated rats.
abstract: Aspartate aminotransferase (AST) activity was measured in the kidneys and uteri of mature female rats to determine what effect, if any, treatment with ethinylestradiol (EE), norgestrel (NOR) or a combination of both hormones might have on the relationship of pyridoxal-PO4 to AST activity. Treatment with EE had no effect on the degree of saturation of kidney AST with pyridoxal-PO4, AST activity/mg kidney or total kidney AST activity compared to controls. Kidney weight was, however, significantly elevated (P < 0.05). The same AST parameters were elevated (P < 0.05) in rats treated with NOR or EE + NOR. Saturation of AST by pyridoxal-PO4 was not altered by hormone treatment in uteri, but AST activity/mg uterus and total uterine activity were lowered by NOR or EE + NOR treatment. Exposure to EE alone elevated these last two parameters. It is noteworthy that the same hormone can both stimulate or inhibit AST, depending on the organ in question. Since progestin-dominant contraceptives are becoming more commonplace, it is important to observe that the progestin was more effective in altering AST parameters than was the estrogen.
mesh_terms: D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism*; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D005260:Female; D007668:Kidney / Q000187:drug effects / Q000201:enzymology*; D009644:Norgestrel / Q000494:pharmacology*; D011732:Pyridoxal Phosphate / Q000378:metabolism; D051381:Rats; D014599:Uterus / Q000187:drug effects / Q000201:enzymology*
chemical_list: D009644:Norgestrel; D004997:Ethinyl Estradiol; D011732:Pyridoxal Phosphate; D001219:Aspartate Aminotransferases