Serum inhibin, FSH, LH and testosterone levels and testicular inhibin content in beef bulls from birth to puberty

Miyamoto, Akio; Umezu, Motoaki; Ishii, Shin‐ichi; Furusawa, Tadashi; Masaki, Junji; Hasegawa, Yoshihisa; Ohta, Michio

doi:10.1016/0378-4320(89)90082-1

Cited by 25 publications

(33 citation statements)

References 38 publications

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“…This is a similar pattern to that reported previously in rams (Schanbacher 1988, Isaacs et al 1995 and in bulls (Miyamoto et al 1989, MacDonald et al 1991 and male rats (Crofton et al 1997) but is different to that found in male monkeys (Keeping et al 1990, Marson et al 1993 and boys (Burger et al 1988, Crofton et al 1997. Nonetheless, a recent study in boys using a specific assay for inhibin B has shown that levels of this hormone are high in the first year of life (Andersson et al 1997).…”

Section: Discussionsupporting

confidence: 73%

“…The testes of prepubertal males synthesize and secrete significant amounts of inhibin and the pattern of secretion of inhibin changes during sexual development although there appears to be substantial differences between species. For example, circulating concentrations of inhibin during sexual maturation have been found to increase in male monkeys (Keeping et al 1990, Marson et al 1993) and in boys (Burger et al 1988, Crofton et al 1997 but to decrease in male rats (Wreford et al 1994), bulls (Miyamoto et al 1989, MacDonald et al 1991 and rams (Schanbacher 1988, Isaacs et al 1995. Several studies indicate that a functional negative feedback system between inhibin and FSH exists before puberty as shown by the decrease in plasma concentrations of inhibin and an increase in FSH in 1-week-old ram lambs (Schanbacher 1988), and the demonstration that active immunization against inhibin in prepubertal ram lambs (Al-Obaidi et al 1987) and bull calves (Martin et al 1991, Schanbacher 1991 caused an increase in plasma concentrations of FSH.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Changes in the suppressive effects of recombinant inhibin A on FSH secretion in ram lambs during sexual maturation: evidence for alterations in the clearance rate of inhibin

Tilbrook

Kretser

Clarke³

1999

Journal of Endocrinology

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We have investigated the effectiveness of human recombinant inhibin A (hr-inhibin A) to suppress the secretion of follicle-stimulating hormone (FSH) in ram lambs from 1 to 18 months of age. Seventeen rams (nine castrated, eight intact) were used. At 1, 3, 6, 9, 12 and 18 months of age the rams were given an i.v. injection of either vehicle or hr-inhibin A (0·64 µg/kg). Blood samples were taken over 24 h. Plasma concentrations of FSH were suppressed in castrated and intact rams following injection of hr-inhibin A with maximal suppression occurring 6 h after injection. Vehicle injection had no effect. At 12 months of age the suppression in FSH was most rapid in castrated rams and was maximal in intact rams. The clearance rate of inhibin was greatest at older ages but during the period of seasonally induced testicular activity, there was a significant decrease in the inhibin clearance. The testicular weight was reduced in rams treated with hr-inhibin A, indicating the importance of FSH for testicular development during the pubertal period. There was no effect of hr-inhibin A on plasma concentrations of luteinizing hormone. We conclude that inhibin is capable of suppressing the secretion of FSH in rams from 1 month of age onwards and that the pituitary gland becomes maximally responsive to the actions of inhibin by the age of puberty.

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Section: Discussionsupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Changes in the suppressive effects of recombinant inhibin A on FSH secretion in ram lambs during sexual maturation: evidence for alterations in the clearance rate of inhibin

Tilbrook

Kretser

Clarke³

1999

Journal of Endocrinology

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“…bull have been described, but reports are conflicting (McCarthyet al, 1979;Amann and Schanbacher, 1983;Miyamoto et al, 1989).…”

Section: Introductionmentioning

confidence: 99%

“…Veeramachaneni et al (1989) demonstrated. by use of immunocytochemical methods, the presence of inhibin within the ovine testis and excurrent duct system, and Miyamoto et al (1989) demonstrated, by using a bioassay for bovine follicular fluid inhibin, the presence of inhibin within the testis of immature beef bulls. In Exp.…”

Section: ~--~---+--~R---+----r---+----~~~---+75mentioning

confidence: 99%

Prepubertal changes in plasma FSH and inhibin in Holstein bull calves: responses to castration and(or) estradiol.

MacDonald

Deaver²,

Schanbacher³

1991

Journal of Animal Science

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The objectives of two studies were to detennine 1) whether plasma concentrations of inhibin (INH) changed with age in prepubertal bulls and whether these changes were related to changes in FSH, testosterone or testis length; and 2) whether castration and(or) estradiol implants affected plasma concentrations of INH and FSH. In Exp. 1, plasma INH remained constant from 4 until 8 wk of age then increased from 120 pM to 202 pM between 8 and 12 wk. Thereafter, INH decreased to 90 pM by 36 wk. Between 4 and 10 wk, plasma FSH increased from .32 to .43 ng/mI, apparently increasing before the initial rise in plasma INH Between 10 and 12 wk, FSH declined from .43 to .33 ng/mI. After 12 wk, FSH increased as INH decreased. Initial increases in testis length and concentrations of plasma testosterone occurred at 14 wk coincident with the second rise in FSH. In Exp. 2, bull calves were either left intact, castrated, castrated and implanted with estradiol, or left intact and implanted with estradiol at 7.5 wk of age. Castration decreased concentrations of INH and increased concentrations of FSH. Castrated calves implanted with estradiol had decreased concentrations of both INH and FSH. Intact bulls implanted with estradiol had decreased concentrations of FSH relative to intact unimplanted bulls; however. concentrations of INH did not display the age-related changes observed in intact, unimplanted bulls. In summary, age-related changes in plasma INH and FSH occur in bulls. Furthermore, plasma concentrations of INH and FSH increased before changes in gonadal size were detected. The bovine testis may be a major source of circulating INH because castration decreased concentrations of plasma INH.

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“…Previous studies that examined the relationship between circulating FSH and inhibin in developing bulls reached contradictory conclusions; two studies found a negative correlation between the plasma levels of inhibin and FSH from 10 to 36 weeks of age [8] or from 2.5 to 108 months [9], whereas Miyamoto et al [10] found a positive correlation between 1 and 8 months. However, the radioimmunoassays (RIAs) used in the above studies were based on antisera directed against the α subunits of inhibin.…”

mentioning

confidence: 84%

Changes in Circulating and Testicular Levels of Inhibin A and B During Postnatal Development in Bulls

Kaneko

Matsuzaki

Noguchi

et al. 2006

Journal of Reproduction and Development

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Abstract. We investigated testicular and circulating levels of dimeric inhibins in Holstein bulls from the infantile to postpubertal periods (5 to 50 weeks of age) and examined the relationship between the profiles of circulating dimeric inhibins and FSH. Concentrations of total inhibin and inhibin B in the testis were highest at 4 to 5 weeks of age but decreased gradually as the bulls aged. Testicular inhibin A levels showed a gradual decline to a nadir at 15 to 26 weeks of age, but by 39 weeks, they were high again. The contents of total inhibin, inhibin A, and inhibin B per testis generally increased with age. Fractionation of testicular homogenates obtained from 15-week-old bulls by a combination of immunoaffinity chromatography and SDS-PAGE confirmed the presence of two major molecular weight forms (32 and 45 kDa) of dimeric inhibins in the testes. Circulating levels of total inhibin and inhibin A showed a significant increase in bulls at around 10 to 14 weeks of age compared to the levels between 5 and 7 weeks of age but decreased thereafter. However, immunoreactivity for inhibin B was not detected in the peripheral circulation, probably because of low sensitivity of the inhibin B assays. The concentrations of plasma FSH were high at 5 weeks of age but declined to lower levels between 11 and 40 weeks, and then increased from 41 weeks onward. There was no significant correlation between the plasma levels of FSH and inhibin A or total inhibin. The results clearly indicate that the bull testis produces inhibin A and B and secretes at least inhibin A into the circulation during postnatal development. However, the profile of circulating FSH in bulls shows no reciprocal relationship with the inhibin A or total inhibin profile during the postnatal period. Key words: Bulls, Circulation, Inhibin A, Inhibin B, Postnatal period, Testis (J. Reprod. Dev. 52: [741][742][743][744][745][746][747][748][749] 2006) ollicle-stimulating hormone is a regulator of testicular growth and function, and its secretion is regulated by a balance between the stimulatory effects of gonadotropin-releasing hormone from the hypothalamus and the inhibitory effects of hormones secreted by the testis. Inhibin is a dimeric protein composed of an α subunit and either a β A subunit (inhibin A) or β B subunit (inhibin B); it is produced in the gonads and suppresses FSH secretion in cultured pituitary cells. In vivo immunoneutralization studies of inhibin have revealed that inhibin functions as a negative regulator of FSH secretion in male rats [1], hamsters [2], goats [3], and cattle [4][5][6][7].Previous studies that examined the relationship

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Serum inhibin, FSH, LH and testosterone levels and testicular inhibin content in beef bulls from birth to puberty

Cited by 25 publications

References 38 publications

Changes in the suppressive effects of recombinant inhibin A on FSH secretion in ram lambs during sexual maturation: evidence for alterations in the clearance rate of inhibin

Changes in the suppressive effects of recombinant inhibin A on FSH secretion in ram lambs during sexual maturation: evidence for alterations in the clearance rate of inhibin

Prepubertal changes in plasma FSH and inhibin in Holstein bull calves: responses to castration and(or) estradiol.

Changes in Circulating and Testicular Levels of Inhibin A and B During Postnatal Development in Bulls

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