Equine Chorionic Gonadotropin Modulates the Expression of Genes Related to the Structure and Function of the Bovine Corpus Luteum.
Authors: Sousa Liza Margareth Medeiros de Carvalho, Mendes Gabriela Pacheco, Campos Danila Barreiro, Baruselli Pietro Sampaio, Papa Paula de Carvalho
Journal: PloS one
Summary
# Editorial Summary Equine chorionic gonadotropin (eCG) is widely used in bovine reproductive management to stimulate ovulation, yet the molecular mechanisms underpinning its effects on corpus luteum function remain incompletely understood. Researchers examined how eCG-based stimulation and superovulation protocols alter gene and protein expression related to insulin signalling, angiogenesis, and tissue remodelling within the bovine corpus luteum, using both in vivo tissue sampling and in vitro luteal cell cultures. Key findings included elevated somatomedin C (IGF-1) in both treated groups, with superovulated animals showing paradoxically lower INSR gene expression but higher INSR protein expression alongside increased growth factor signalling; stimulated animals demonstrated enhanced angiogenic capacity (higher angiopoietin and plasminogen activator expression) and reduced matrix-degrading protease activity compared to controls. These molecular signatures suggest that stimulation promotes vascular development and tissue plasticity to support progesterone production, whilst superovulation triggers cellular proliferation with enhanced metabolic substrate availability—mechanistically distinct responses to the same hormone at different doses. For equine professionals, whilst this research directly addresses cattle reproduction, the fundamental biology of eCG-responsive signalling pathways and corpus luteum function shares considerable homology across species, offering insights into how reproductive hormone protocols might differentially influence luteal longevity, progesterone output, and tissue remodelling in mares undergoing similar treatment regimens.
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Practical Takeaways
- •eCG-based stimulation protocols induce distinct molecular changes: superovulation drives energy availability to support increased follicle development, while stimulation enhances vascularization and tissue remodeling capacity
- •These findings support the biological basis for using eCG in reproductive management programs, with differential effects depending on whether stimulation or superovulation is the goal
- •Understanding these gene expression changes helps explain clinical responses to eCG and may inform optimization of breeding protocols
Key Findings
- •Superovulatory eCG treatment increased somatomedin C levels and upregulated genes providing energy substrate to the corpus luteum compared to controls (P=0.01)
- •Stimulatory eCG treatment enhanced angiogenesis markers (ANGPT1, PLAU) and extracellular matrix plasticity while decreasing protease expression (PRSS2, MMP9)
- •Both stimulated and superovulated groups showed lower INSR mRNA expression but superovulated animals displayed higher INSR protein expression and elevated IGF1/IGFR1 signaling
- •In vitro eCG directly stimulated luteal cell progesterone production and increased INSR and GLUT4 protein expression