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Intrafollicular and systemic serotonin, oestradiol and progesterone concentrations in cycling mares
Author(s) -
Satué Katiuska,
Fazio Esterina,
Ferlazzo Adriana,
Medica Pietro
Publication year - 2019
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/rda.13545
Subject(s) - ovulation , medicine , follicle , endocrinology , serotonin , follicular phase , follicular fluid , ovarian follicle , serotonergic , biology , hair follicle , chemistry , andrology , hormone , oocyte , receptor , fishery , embryo
Abstract The hypothesis that a local serotonergic network might also exist in the follicle of mares remains poorly documented, with exception for humans and laboratory species. For this reason, the aim of the present study was to clarify this possibility, investigating intrafollicular serotonin concentrations of the cycling mare at ovulation time. Sixty ovaries collected from 30 clinically healthy mares of slaughterhouse meat production with clinically normal reproductive tracts after slaughtering were evaluated. Blood samples were taken prior to sacrifice. Follicles were classified in three categories in relation to size, as small (20–30 mm), medium (31–40 mm) and large (>41 mm), and the follicular fluid samples were extracted from each follicle. Intrafollicular and systemic serotonin (5‐HT), oestradiol‐17β (E 2 ) and progesterone (P 4 ) were determined by means of enzyme‐linked immunosorbent assay and RIA, respectively. Intrafollicular 5‐HT, E 2 and P 4 concentrations were higher than systemic ones ( p < .05). 5‐HT concentrations increased in larger compared to medium follicles, without differences compared to small size follicles ( p < .05). 5‐HT and E 2 ( r = .79) and 5‐HT and P 4 ( r = .79; p < .05) were positively correlated. 5‐HT and P 4 concentrations in follicular fluid increased progressively with the increase in follicular size ( p < .05). Follicle diameter and E 2 ( r = .85) and P 4 ( r = .68) were correlated ( p < .05). Since serotonin interacts with steroids, its role on steroidogenesis during growth of the dominant follicle may be suggested.