Progesterone dose during synchronization treatment alters luteinizing hormone receptor and steroidogenic enzyme mRNA abundances in granulosa cells of Nellore heifers

The objective was to investigate effects of progesterone (P4) dose on abundance luteinizing hormone receptor (LHCGR), aromatase (CYP19A1), 3β-hydroxysteroid dehydrogenase (HSD3B1), and other steroidogenic mRNA transcripts in granulosa cells from dominant follicles. Nellore heifers were assigned one six groups: new, first-use controlled internal drug release device (CIDR1) inserted for 5 days (Large-P4-dose-D5; n = 7) or 6 (Large-P4-dose-D6; 8), prostaglandin (PG)F2α administered D0 1 previously-used CIDR (CIDR3) (Small- P4-dose-D5; 8) (Small-P4-dose-D6; CIDR1 removed plus PGF2α D5 (Large-P4-dose-proestrus (PE); 7), CIDR3 1, (Small-P4-dose-PE; 7). Duration P4 treatment (D5 compared D6) affected abundances CYP19A1 transcripts, with there being greater D6 than (P ≤ 0.05). Heifers treated the large had a smaller follicle, less serum intra-follicular estradiol (E2) concentrations 0.05) lesser LHCGR, CYP19A1, HSD3B1 transcript induce PE larger follicle diameter 0.09), E2 group. Overall, doses resulted HSD3B1, transcripts; thus, potentially leading development follicles concentrations.