Stress alters the activity of Leydig cells dependently on the diurnal time

Background The increasing amount of data points to the circadian timing system as an essential part of processes regulating androgen homeostasis. However, the relationship between stress response, timekeeping-, and steroidogenesis-related systems is unexplored. Objective The purpose of the study was to analyze the stress-response of the testosterone-producing Leydig cells depending on the stressful event’s time. Materials and methods The study was designed to follow the effects of 3-hour immobilization (IMO) applied at different periods during the day. The IMO performed once (1xIMO) or repeated in 10 consecutive days (10xIMO). Principal-component-analysis (PCA) followed the expression study of the clock and steroidogenic-related genes in Leydig cells. Results Both types of IMO in all investigated periods increased corticosterone and decreased testosterone blood level. Transcriptional analysis revealed different sensitivity to IMO events depending on the circadian time. The majority of steroidogenesis-related genes ( Lhcgr, Cyp11a1, Cyp17a1, Hsd3b1/2 ) were down-regulated in the inactive but unchanged or even up-regulated in the active phase of the day. Both types of IMO potentiated the expression of clock elements Bmal1 /BMAL1, Per1/ PER1 regardless of the day’s stage and reduced Reverba in the inactive phase. The PCA confirmed a major shift, for both IMO-types, in the transcription of steroidogenesis and clock genes across the inactive/active phase. Further, the diurnal pattern of the glucocorticoid receptor ( Nr3c1 /GR) expression in Leydig cells was increased in the inactive phase due to 10xIMO. The observed time-dependent IMO-response of the Leydig cells correlated with different GR engagements. Discussion Stress- and the circadian-system coordinatively shape Leydig cell’s physiology, assuming diverse GR engagement as a possible factor in mediating the diurnal effect of stress. Conclusion The Leydig cell’s stress-response depends on the time of the stressful situation, emphasizing the importance of circadian activity in supporting androgen homeostasis and male fertility.