A review on molecular regulation of male reproductive hormones and signaling pathways: Emerging mechanisms and research gap.

Male infertility is complex, driven by impaired endocrine signalling, germ-somatic cell communication, and epigenetic regulation of spermatogenesis. LH/cAMP/PKA signalling in Leydig cells and FSH-mediated regulation in Sertoli cells have been extensively studied. The combined effects of these pathways on testicular physiology and clinical infertility are unknown. This review integrates hypothalamic-pituitary-gonadal axis signalling, intra-testicular epigenetic oversight, and environmental variables at the systems level. Integrating LH and FSH-dependent signalling with somatic cell activity, epigenetic programming during spermatogenesis, and endocrine disruptor effects on these networks. Despite recent improvements in single-cell and spatial transcriptomics, testicular heterogeneity and its integration processes remain unexplained. This review identifies key barriers that hinder molecular discoveries from becoming clinical diagnoses and therapies. This paradigm links biological pathways to infertility symptoms. It provides new possibilities for biomarker development and targeted therapeutics by including endocrine, epigenetic, and environmental factors on testicular function, prompting future research into translational routes that connect molecular endocrinology and clinical care for infertility.