Review: Luteal prostaglandins: mechanisms regulating luteal survival and demise in ruminants

Prostaglandins as local regulators of ovarian physiology in ruminants

“…In cases of an infertile cycle, uterine prostaglandins (PGF) regulate the luteal regression process (luteolysis), the necessary functional phase of the CL that enables the beginning of the next oestrous cycle (Jimoh et al, 2022;Weems et al, 2006). The typical symptoms of luteal regression are the immediate decline in progesterone production, which is accompanied by obstructions in the vasculature, blood flow decline, as well as the initiation of the rapid death of CL cells (Acosta et al, 2002;Pate & Hughes, 2023).…”

“…PGE tissue concentration showed a similar expression profile, significantly increasing during the late luteal phase (Days 13-17) and an immediate decrease during the luteal regression (Figure 2). Interestingly, in ruminants, the CL synthesizes PGF and PGE in high concentrations, equal to or greater than those secreted by the uterus (Pate & Hughes, 2023). Prostaglandins (PGF and PGE) are involved in local (paracrine) mechanisms that regulate CL formation, stimulating progesterone production by bovine luteal cells (Kotwica et al, 2003).…”

“…Besides endocrine (uterine PGF), intraluteal prostaglandins and a range of other paracrine factors are considered crucial in the luteolytic cascade. The above-mentioned angiogenic factors (VEGF, FGF, HIF, ANPT), especially vasoactive peptides (endothelin and angiotensin), extracellular matrix-degrading proteases, apoptotic factors and a range of specific cytokines and enzymes seem to be very important even during the CL regression (Atli et al, 2022;Berisha et al, 2009;Jaroszewski et al, 2003;Pate & Hughes, 2023;Smith et al, 1999).…”

“…It is also associated with subsequent changes in locally produced proangiogenic mediators such as HIF, VEGF and angiopoietins, which have a crucial impact on the vascular stability of the CL as an important component in the luteolytic cascade. During experimental luteolysis, functional effects of exogenous PGF have been documented in the regulation of extracellular matrix-degrading proteases, vasoactive peptides, and various growth factors and other peptides (Atli et al, 2012;Galvão et al, 2018;Jiang et al, 2011;Nishimura & Okuda, 2020;Pate, 2020;Pate & Hughes, 2023). In addition, they affect the regulation of various proinflammatory cytokines, which promote apoptotic death of endothelial and luteal cells and support phagocytosis, especially during the structural luteolysis, leading to the demise of the gland (Friedman et al, 2000;Hojo et al, 2019;Jonczyk et al, 2019;Knickerbocker et al, 1988;Meidan et al, 1999;Pate & Hughes, 2023).…”

“…During experimental luteolysis, functional effects of exogenous PGF have been documented in the regulation of extracellular matrix-degrading proteases, vasoactive peptides, and various growth factors and other peptides (Atli et al, 2012;Galvão et al, 2018;Jiang et al, 2011;Nishimura & Okuda, 2020;Pate, 2020;Pate & Hughes, 2023). In addition, they affect the regulation of various proinflammatory cytokines, which promote apoptotic death of endothelial and luteal cells and support phagocytosis, especially during the structural luteolysis, leading to the demise of the gland (Friedman et al, 2000;Hojo et al, 2019;Jonczyk et al, 2019;Knickerbocker et al, 1988;Meidan et al, 1999;Pate & Hughes, 2023). In addition, prostaglandins' specific expression and localization pattern in the CL showed that prostaglandins might be key elements of local regulation.…”