INTRODUCTION: A contrary relation between prolonged stress and normal reproductive efficiency has frequently been observed in domestic animals, and the action of various stressors is manifested primarily by an increase in the level of glucocorticoids in blood. AIM(S): This study aimed to determine the central and peripheral mechanisms governing GnRH biosynthesis and LH secretion in prolonged-stressed follicular‑phase sheep. They included two main experimental approaches: (1) an investigation of the effects of physical stress on GnRH and GnRH receptor (GnRHR) biosynthesis, and (2) examination of the influence of stressor on levels of mRNAs encoding kisspeptin (Kiss1) and the Kiss1 receptor (Kiss1r). Furthermore, plasma LH and cortisol concentrations were also measured. METHOD(S): The ELISA technique was used to analyse the effects of stress on levels of post-translational products of genes encoding the GnRH ligand and GnRH receptor (GnRHR) in the preoptic area (POA), anterior (AH) and ventromedial (VMH) hypothalamus, stalk/median eminence (SME), and GnRHR in the anterior pituitary (AP). Real‑time PCR was chosen for determination of the effects of stress on Kiss1 mRNA levels in the POA and the VMH the including arcuate nucleus (VMH/ARC), and on Kiss1r mRNA abundance in POA‑hypothalamic structures. These analyses were supplemented by radioimmunoassay (RIA) and ELISA methods for the measurement of LH and cortisol levels in blood, respectively. RESULTS: Stress decreased GnRH and GnRHR biosynthesis in the hypothalamus, and GnRHR in the AP. Moreover, stress lowered plasma LH concentration and levels of Kiss1 mRNA in the POA and VMH/ARC as well as Kiss1r mRNA in these structures and in the SME. An increase in plasma cortisol concentration under stress conditions was also observed. CONCLUSIONS: This study demonstrates that stress affects GnRH/GnRHR biosynthesis and LH secretion in follicular-phase sheep, conceivably via both central and peripheral mechanisms including Kiss1 neuronal activity and action of cortisol.