Skip Navigation
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Your Environment. Your Health.

Publication Detail

Title: Mechanisms of glucagon-induced increases in rates of cytochrome P450-dependent pentoxyphenoxazone O-depentylation in cultured rat conceptuses.

Authors: Lee, Q P; Juchau, M R

Published In Reprod Toxicol, (1992)

Abstract: Inclusions of glucagon (1.0 or 2.0 microM, final concentrations) in the media of cultured whole rat conceptuses resulted in concentration-dependent increases in measured rates of O-depentylation of pentoxyphenoxazone in cell-free preparations of conceptal tissues. Enzymic activities were assayed 24 h after initial exposure of the conceptuses to glucagon on day 10 of gestation. Glucagon elicited increases in tissue levels of cAMP that were parallel to those produced by 3-isobutyl-1-methylxanthine over the same time period. Tissue cAMP levels were maximal after 2 h, rapidly returned to control levels and were also equal to background levels in controls after the 24 h culture period. Dibutyryl cAMP, 3-isobutyl-1-methylxanthine, theophylline, and RO201724, a cAMP-selective phosphodiesterase inhibitor, each produced 75 to 100% increases in O-dealkylase activity. Dibutyryl cGMP and two phosphodiesterase inhibitors, enoximone (cGMP-inhibited) and zaprinast (cGMP-specific), each failed to produce statistically significant increases in O-depentylase activity. The O-depentylase was tentatively identified as a conceptus-specific P450 cytochrome that is synthesized predominantly in tissues of the visceral yolk sac. The results indicated that glucagon may upregulate a unique, xenobiotic-biotransforming P450(s) via a long-term mechanism(s) specifically involving tissue cAMP.

PubMed ID: 1337707 Exiting the NIEHS site

MeSH Terms: Animals; Culture Techniques; Cyclic AMP/metabolism; Cytochrome P-450 CYP2B1; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System/metabolism*; Embryo, Mammalian/drug effects*; Embryo, Mammalian/enzymology; Glucagon/pharmacology*; Metyrapone/pharmacology; Nucleotides, Cyclic/pharmacology; Oxazines/analysis; Oxazines/metabolism*; Oxidoreductases/antagonists & inhibitors; Oxidoreductases/metabolism*; Phosphodiesterase Inhibitors/pharmacology; Rats; Rats, Sprague-Dawley

to Top