Estradiol is a steroid hormone belonging to the estrogen group, which plays a significant role in various physiological processes in horses. It is primarily produced by the ovaries and is involved in the regulation of the estrous cycle, reproductive behavior, and secondary sexual characteristics. In mares, estradiol levels fluctuate throughout the reproductive cycle, influencing follicular development and ovulation. Additionally, estradiol has effects on bone density, muscle growth, and metabolic processes. This page compiles peer-reviewed research studies and scholarly articles that explore the production, function, and clinical implications of estradiol in equine physiology and reproductive health.
Amaral A, Cerveira-Pinto M, Santos C, Kordowitzki P, Skarzynski D, Ferreira-Dias G, Szóstek-Mioduchowska A.Transforming growth factor (TGF)-β1 is a pro-fibrotic cytokine that affects extracellular matrix (ECM) deposition and fibroblast activity. 17β-Estradiol (E), the dominant ovarian steroid during the follicular phase (FLP) of the estrous cycle, can also influence ECM remodeling and fibrosis, through prostaglandin (PG) synthesis. PGs have opposing roles in fibrosis, with PGE₂ showing anti-fibrotic effects and PGF₂α promoting fibrosis. Equine endometrosis, whose main pathological feature is fibrosis, is marked by chronic inflammation and ECM accumulation, and may involve mediators like TGF-...
Khan Y, Gautier C, Aurich C, El-Shalofy A.Letrozole is a potent and highly selective third-generation aromatase inhibitor. In the present study, we aimed to investigate the effects of letrozole treatment of non-pregnant mares on estrous cycle characteristics. Cyclic, non-lactating mares (n = 9) were included. After estrus synchronization, mares were monitored to detect ovulation (d0:) of the treatment cycle. Each three mares were randomly assigned to one of three treatments: control, 0.5, and 1 mg/kg body weight letrozole in three consecutive cycles (d7 to d13 of the treatment cycle). Mares were inseminated in the estrus after trea...
Sala-Ayala L, Cuervo-Arango J, Martínez Boví R.Endometrial edema is an ultrasonographic sign of estrus in mares and is positively associated with fertility. This study aimed to evaluate the influence of follicular size, systemic progesterone (P4), and exogenous estradiol benzoate (EB) on the onset and duration of endometrial edema. In Experiment 1, anestrus (n = 4) and diestrus mares (n = 4) received 4 mg of EB intramuscularly; edema scores and plasma P4 were monitored over four days. In a complementary group (n = 5), mares were monitored until ovulation, then administered 4 mg of EB and examined every 12 h for 48 h. In Experimen...
Pinto-Bravo P, Rebordão MR, Amaral AS, Szóstek-Mioduchowska A, Fernandes C, Galvão AM, Silva E, Alpoim-Moreira J, da Costa RPR, Skarzynski DJ....Oviduct glycoprotein 1 (OVGP1) is a key protein involved in oviductal functions. β-estradiol (E) and progesterone (P), oxytocin (OXT) and tumor necrosis factor-α (TNFα) modulate the equine oviduct function, through prostaglandin regulation. The objective was to evaluate OVGP1 expression within each equine oviduct segment (infundibulum, ampulla isthmus), throughout the estrous cycle. The in vitro effect of (i) E, P, OXT, TNFα; and (ii) spermatozoa, on oviduct OVGP1 transcription and secretion was studied. Gene transcription was assessed by real-time PCR; protein expression by western blot; ...
Li M, Lin J, Ma C, Wei G, Hu Q, Li X.L-selenomethionine (L-SeMet), a highly bioavailable organic form of selenium, plays a critical role in maintaining antioxidant homeostasis, regulating reproductive hormone secretion, and improving intestinal microbial ecology. Previous studies have demonstrated that appropriate supplementation with L-SeMet can significantly enhance the production performance and health status of ruminants. However, the nutritional regulatory mechanisms and physiological effects of L-SeMet in monogastric herbivores, particularly horses during mid- to late gestation, remain inadequately understood. Therefore, th...
