Microarray analysis of the transcriptome in the primate corpus luteum during chorionic gonadotropin administration simulating early pregnancy.. Macaca mulatta

To explore chorionic gonadotropin (CG)-regulated gene expression in the primate corpus luteum (CL), adult female rhesus macaques were treated with a model of simulated early pregnancy (SEP). Total RNA was isolated from individual CL and hybridized to Affymetrix™ GeneChip Rhesus Macaque Genome Arrays The level of 1192 transcripts changed expression > 2-fold (one-way ANOVA, FDR correction; P2 fold (one-way ANOVA, FDR correction; P<0.05) between the two groups. Clustering of samples revealed that the SEP samples possessed the most related transcript expression profiles. Regressed CL (days 18-19, around menses) were the most unlike all other CL. The most affected KEGG pathway was Steroid Biosynthesis, and most significantly absent pathways following SEP treatment includes groups of genes whose products promote cell-death. By further comparing the genome-wide changes in luteal gene expression during rescue in SEP, with those in CL during luteolysis in the natural menstrual cycle, it is possible to identify key regulatory pathways promoting fertility. Overall design: Simulated early pregnancy (SEP) treatment was begun on day 9 as Duffy and Stouffer (1997) by treatment of females with recombinant human chorionic gonadotropin (hCG; Novarel™, Ferring Pharmaceuticals Inc. Parsippany, NJ, USA) in increasing dosages (15, 30,45,90,180,360,720,1440, and 2880 IU) twice daily by intramuscular injection. CL were collected by laparotomy on days 10, 12, 15, and 18, representing 1, 3, 6 and 9 days of hCG treatment (n=4 CL/day). Additionally, luteal day 10 untreated CL were collected to serve as baseline controls for SEP CL. All CL were dissected away from luteal tissue, sectioned, and snap-frozen in liquid nitrogen and stored at -80°C until RNA and protein isolation by TRIzol® extraction (Invitrogen, Carlsbad, CA, USA) according to manufacturer’s protocols.