ORGANOGENESIS-STAGE CYTOCHROME-P450 ISOFORMS - UTILIZATION OF PCR FOR DETECTION OF CYP1A1 MESSENGER-RNA IN RAT CONCEPTAL TISSUES

Utilizing the reverse transcriptase-linked polymerase chain reaction, we analyzed the capacity of three groups of rat conceptal tissues to express cytochrome P4501A1 (CYP1A1) mRNA during the dysmorphogenesis-sensitive stage of organogenesis. The visceral yolk sac, ectoplacental cone and embryo proper each were investigated on day 12 of gestation with and without prior exposure in utero to 3-methylcholanthrene as inducing agent. With two sets of discriminating oligonucleotide primers, definitive, reproducible signals were detectable only in tissues from 3-methylcholanthrene preexposed conceptuses. Signals of highest intensity were observed with visceral volk sac tissues and signals of lowest intensity were observed with tissues of the embryo per se. Specificities of the amplified cDNAs were verified using Southern blotting with hybridization to an internal oligonucleotide probe. The results indicate that organogenesis-stage conceptal tissues of the rat will express CYP1A1 mRNA in response to environmental transregulating agents. © 1991.