Change in Circulating Follicle-Stimulating Hormone, Luteinizing Hormone, Immunoreactive Inhibin, Progesterone, Testosterone and Estradiol-17.BETA. in Fillies from Birth to 6 Months of Age

Nakai, Rie; Wang, Qiang; Tanaka, Yumiko; Tsunoda, Nobuo; Taniyama, Hiroyuki; Haramaki, Shigeyuki; Nambo, Yasuo; Watanabe, Gen; Taya, Kazuyoshi

doi:10.1294/jes.18.85

Cited by 7 publications

(10 citation statements)

References 14 publications

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“…Sertoli cell number fluctuates in horses according to the season [ 9 ] and testes produces remarkable amounts of estradiol. The concentration of gonadal and pituitary hormones in fillies has been reported previously [ 15 ] from our lab. Similar study in Thoroughbred colts is lacking.…”

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confidence: 66%

Post-Natal Dynamic Changes in Circulating Follicle-Stimulating Hormone, Luteinizing Hormone, Immunoreactive Inhibin, Progesterone, Testosterone and Estradiol-17.BETA. in Thoroughbred Colts until 6 Months of Age

Dhakal

Tsunoda

Nakai

et al. 2011

JES

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The aim of present study was to clarify the post-natal profile of follicle-stimulating hormone (FSH), luteinizing hormone (LH), immunoreactive (ir)-inhibin, progesterone, testosterone, and estradiol-17β, and their relationships in Thoroughbred colts. Six hundred and thirty-six colts were used for the study. Single plasma samples from each animal were harvested from the blood drawn through jugular venipuncture. The subjects were born with high amounts of progesterone, testosterone, and estradiol-17β, all of which dropped significantly and remained at lower levels till the end of 6 months. FSH decreased transiently after birth until day 12 and then gradually increased to peak at day 100 which then maintained in lesser levels towards the end of the studied period. LH was highest during birth which decreased until day 26 and then increased slowly to sub-birth levels up to day 90. Animals were born with high amounts of ir-inhibin. It dropped slowly and halved by day 20 and then decreased towards rest of the studied period. The increase in FSH is negatively correlated with the declining ir-inhibin levels. The early increase in FSH can be the indication of early post-natal maturation of the hypothalamic pituitary testicular axis that ultimately might be responsible for priming the testes for future development.

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confidence: 66%

Post-Natal Dynamic Changes in Circulating Follicle-Stimulating Hormone, Luteinizing Hormone, Immunoreactive Inhibin, Progesterone, Testosterone and Estradiol-17.BETA. in Thoroughbred Colts until 6 Months of Age

Dhakal

Tsunoda

Nakai

et al. 2011

JES

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“…Inhibin has been implicated as a marker of testicular function of stallions [23][24][25], and a gradual increase in circulating inhibin is shown during the follicular phase in mares [26][27][28]. Both colts and fillies were born with a high amount of steroid hormones that dropped abruptly within 24 hours [10,11]. The fetal gonads of horse provide precursors for maternal estrogens [21,22], and the high concentration at birth is the carryover from the intrauterine maternal environment and subsequent metabolism after birth.…”

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confidence: 99%

“…Previous studies provided information on relatively shorter periods [10,11] of developmental periods after birth, and those studies focused on certain hormones [3,4,6] only. In seasonal breeders, there is evidence for the involvement of both photoperiodic cues and degree of maturity in the onset of puberty [8].…”

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Circulating Pituitary and Gonadal Hormones in Spring-born Thoroughbred Fillies and Colts from Birth to Puberty

et al. 2012

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Abstract. The present study was conducted to elucidate the profile of circulating gonadotropins and gonadal hormones from birth to puberty and relationship between gonadal seasonality and hormonal secretion in both sexes of Thoroughbred horses. Spring-born colts (n=6) and fillies (n=9) were blood sampled weekly from jugular vein from birth to 60 weeks of age. Circulating FSH, LH, prolactin, testosterone, progesterone, estradiol-17β, and immunoreactive (ir)-inhibin were measured by radioimmunoassay. In both sexes, the steroid hormones levels were remarkably high at birth, rapidly dropped within a week and remained at the lower levels until the start of second spring after birth. Ir-inhibin was also high during the birth, remaining lowest during winter and again increasing towards the second summer. There was an increase in FSH concentration in foals during the first summer months after birth and in the next summer, the FSH concentration along with that of LH increased significantly. The seasonal increase in circulating prolactin was remarkable even in the first year, and no differences were noted between the two summers. These results clearly demonstrated that the hypothalamo-pituitary axis is already responsive to changes in photoperiod and secrete prolactin similar to adult horses, but pituitary gonadotrophs for FSH and LH secretion is less sensitive. When the values of these hormones in the second breeding season after birth were compared with adult values of the respective sex in the breeding season, no significant differences were observed, indicating that spring-born fillies and colts have already attained the stage of puberty at the second breeding season after birth. Key words: Prolactin, Puberty, Seasonality, Thoroughbred (J. Reprod. Dev. 58: [522][523][524][525][526][527][528][529][530] 2012) E quines are seasonal breeders with activity being highest as days grow longer [1]. There is no univocal reporting of the age of puberty in horses, which has been reported to vary in the range of 7.8-37 months [2]. This variation can be attributed to differences in breeds [3][4][5], locales, management and puberty definition [6,7]. Furthermore, there have been few studies on Thoroughbreds [7][8][9], and most of them were conducted in southern hemisphere. Geographical location influences the season, and there have been fewer reports regarding puberty in horses from the northern hemisphere.There is a dearth of information on the characteristics of circulating gonadotropins and gonadal hormones in Thoroughbred foals immediately after birth through pre-pubertal age until puberty. Previous studies provided information on relatively shorter periods [10,11] of developmental periods after birth, and those studies focused on certain hormones [3,4,6] only. In seasonal breeders, there is evidence for the involvement of both photoperiodic cues and degree of maturity in the onset of puberty [8]. The photoperiodic information is thought to be conveyed to the reproductive and prolactin axis via changes in circulating concentra...

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“…W pierwszym dniu po urodzeniu się, stężenie progesteronu i estradiolu w plazmie krwi obwodowej źrebięcia jest wysokie, wynosi około 5,52 ng/ml i 154 pg/ ml, odpowiednio, po czym stopniowo maleje osiągając już od około drugiego tygodnia życia bardzo niskie wartości (6,23). Uważa się, że hormony obecne we krwi nowo narodzonych źrebiąt są pochodzenia łożyskowego, co potwierdza immunoekspresja podstawowych enzymów steroidogenezy, stwierdzona w drugiej połowie ciąży w łożysku klaczy (1).…”

Section: Oogeneza I Folikulogenezaunclassified

Sexual maturity of mares and prospects for shortening the intergenerational period in horses

Młodawska¹,

Tischner²

2019

Medycyna Weterynaryjna

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The aim of the study is to present current knowledge on the mechanisms regulating puberty in mares and the possibility of shortening the intergenerational period in horses through modern animal reproduction biotechnology. The study discusses fetal sex recognition in horses by means of ultrasound, pre- and postnatal development of mare gonads, oogenesis and folliculogenesis, as well as the process of selection and elimination of oocytes. It also describes the role of gonadotropins, ovarian hormonal activity and morphological changes occurring during sexual maturation. It has been shown that about 37% of mares attain sexual maturity in the first year of life. It has also been documented that one-year and two-year-old fillies produce normal embryos that can be used for transplantation and give offspring. It has also been proved that embryos can be produced in vitro from oocytes of juvenile mares. There is hope that acquiring preantral follicles from the ovary and their in vitro culture until the oocyte reaches full maturity for fertilization will permit us to obtain embryos and offspring from mares, including those sexually immature. These methods, combined with in vitro fertilization and embryo transfer techniques, have already made it possible to obtain normal embryos and even live-born offspring in other mammals.

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Change in Circulating Follicle-Stimulating Hormone, Luteinizing Hormone, Immunoreactive Inhibin, Progesterone, Testosterone and Estradiol-17.BETA. in Fillies from Birth to 6 Months of Age

Abstract: The relationship among circulating levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), immunoreactive (ir) inhibin

Cited by 7 publications

References 14 publications

Post-Natal Dynamic Changes in Circulating Follicle-Stimulating Hormone, Luteinizing Hormone, Immunoreactive Inhibin, Progesterone, Testosterone and Estradiol-17.BETA. in Thoroughbred Colts until 6 Months of Age

Post-Natal Dynamic Changes in Circulating Follicle-Stimulating Hormone, Luteinizing Hormone, Immunoreactive Inhibin, Progesterone, Testosterone and Estradiol-17.BETA. in Thoroughbred Colts until 6 Months of Age

Circulating Pituitary and Gonadal Hormones in Spring-born Thoroughbred Fillies and Colts from Birth to Puberty

Sexual maturity of mares and prospects for shortening the intergenerational period in horses

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