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, Pramod; Tsunoda, Nobuo; Nakai, Rie; Nagaoka, Kentaro; Nambo, Yasuo; Sato, Fumio; Taniyama, Hiroyuki; Watanabe, Gen; Taya, Kazuyoshi

doi:10.1294/jes.22.9

Cited by 8 publications

(10 citation statements)

References 19 publications

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“…In previous studies on circulating inhibin, FSH, LH and testosterone levels in relation to age in bull calves [ 7 , 8 , 9 , 18 ], pigs [ 10 , 22 ] and horses [ 2 , 3 ] it was reported that circulating inhibin concentration is higher in the sexually immature stage than the mature stage. Similarly, it was reported that the circulating inhibin level is remarkably high in calves, until they reach sexual maturation [ 17 ].…”

Section: Discussionmentioning

confidence: 99%

Circulating gonadotropins and testicular hormones during sexual maturation and annual changes in male bottlenose dolphins (<i>Tursiops truncatus</i>)

Katsumata¹,

Jaroenporn

Ueda

et al. 2017

The Journal of Veterinary Medical Science

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To reveal the reproductive biology in male bottlenose dolphins (Tursiops truncatus), circulating gonadotropins (follicle stimulating hormone [FSH] and luteinizing hormone [LH]) and testicular hormones (testosterone and inhibin) were monitored for 8−12 years in 2 captive bottlenose dolphins (Mars and Regulus). During the study period, Mars was undergoing sexual maturation, whereas Regulus was already mature at the beginning of the study. Assuming that Mars had reached sexual maturity when the significant increase in circulating testosterone levels was observed, serum concentration of inhibin was higher in the sexually immature stage than in the mature stage, whereas the serum concentration of FSH was higher in the sexually mature stage than in the immature stage. No difference was observed in the LH levels between pre- and post-sexual maturation. There was a significant increase in serum concentration of testosterone during spring in both animals. These results suggest that the mechanism responsible for regulating FSH secretion by inhibin functions during the sexually immature stage in this species.

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Section: Discussionmentioning

confidence: 99%

Circulating gonadotropins and testicular hormones during sexual maturation and annual changes in male bottlenose dolphins (<i>Tursiops truncatus</i>)

Katsumata¹,

Jaroenporn

Ueda

et al. 2017

The Journal of Veterinary Medical Science

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“…Plasma concentrations of FSH [23] and LH [7] were determined by homologous double-antibody equine radioimmunoassay methods as described previously. Intra-and interassay coefficients of variance were 4.9 and 12.2% for FSH and 12.6 and 15.1% for LH, respectively.…”

Section: Experiments 1: Case Report On the Induction Of Lactation And mentioning

confidence: 99%

Successful Induction of Lactation in a Barren Thoroughbred Mare: Growth of a Foal Raised on Induced Lactation and the Corresponding Maternal Hormone Profiles

Korosue

Murase

Sato

et al. 2012

The Journal of Veterinary Medical Science

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ABSTRAcT. The purpose of this study was to demonstrate that a barren parous Thoroughbred mare with lactation induced by hormonal treatment can be introduced to an orphan foal at the same farm and that the mare can become pregnant after the end of the hormonal treatment. An additional purpose was to investigate the changes in the plasma concentrations of prolactin, estradiol-17β, progesterone, folliclestimulating hormone, and luteinizing hormone before, during, and after hormonal treatment. The difference in body weight between the adopted foal and the control foals, which were at the same farm and raised by their natural mothers, was 17 kg at 24 weeks old, when the foals were weaned. However, the adopted foal and the control foals had almost the same weight at 35 weeks old and later. The first ovulation after hormonal treatment was confirmed 10 days after the end of hormonal treatment and then the normal estrous cycle resumed. Furthermore, the changes in plasma progesterone, estradiol-17β, follicle-stimulating hormone, and luteinizing hormone showed regular patterns after the first ovulation. Conception was confirmed in the fifth ovulation. Meanwhile, another study demonstrated that conception was confirmed in the first ovulation after hormonal treatment. The present study is the first to demonstrate the hormonal profiles during and after induction of lactation in a Thoroughbred mare. This approach is useful for solving the economic and epidemic problems of introducing a nurse mare to an orphan foal. KEY WORDS: hormonal treatment, horse, induction of lactation.

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“…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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confidence: 99%

“…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%

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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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

Cited by 8 publications

References 19 publications

Circulating gonadotropins and testicular hormones during sexual maturation and annual changes in male bottlenose dolphins (<i>Tursiops truncatus</i>)

Circulating gonadotropins and testicular hormones during sexual maturation and annual changes in male bottlenose dolphins (<i>Tursiops truncatus</i>)

Successful Induction of Lactation in a Barren Thoroughbred Mare: Growth of a Foal Raised on Induced Lactation and the Corresponding Maternal Hormone Profiles

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

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