Variation of Plasma Testosterone in Developing Friesian Bulls

Secchiari, Pier Lorenzo; Martorana, F.; Pellegrini, S.; Luisi, M

doi:10.2527/jas1976.422405x

Cited by 54 publications

(29 citation statements)

References 12 publications

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“…As was previously suggested, the early postnatal increase in LH secretion, noted in the present study, was caused by an increase in LH pulse frequency (McCarthy et al 1979, Amann & Walker 1983, Evans et al 1993, 1996. It is probable that the high frequency discharge of LH between 4 and 25 weeks of age influenced Leydig cell differentiation and maturation, and led to increased secretion of testosterone after 12 weeks of age (Rawlings et al 1972, 1978, Secchiari et al 1976, Amann 1983, Amann & Walker 1983, Rawlings & Cook 1986, Mendis-Handagama & Ariyaratne 2001. The marked increase in mean serum testosterone concentrations from 16 to 20 weeks of age, noted in the present study, probably terminated the early postnatal increase in serum concentrations of LH and FSH (Rawlings et al 1978.…”

Section: Discussionsupporting

confidence: 57%

“…Amann (1983) suggested that in bull calves the enhanced testosterone production after 28 weeks of age involved increased cellular synthesis or increased Leydig cell numbers. The peaks in testosterone production seen at 20 and 32 weeks of age in the present study, with the intervening trough, have previously been noted (Rawlings et al 1972, 1978, Secchiari et al 1976. Progenitor Leydig cells and Leydig cells resident in the testicular interstitium are the target cells for LH action (Shanbacher 1979 2001).…”

Section: Discussionmentioning

confidence: 73%

“…In developing bulls, the patterns of serum FSH concentrations are variable; with reports of no change with time (McCarthy et al 1979), a slight increase in the early postnatal period , Aravindakshan et al 2000, and an increase from 4 to 32 weeks of age (Amann & Walker 1983). During the early rise in serum LH concentrations, serum testosterone concentrations are low, increasing markedly after 28 weeks of age and reaching adult concentrations by 40 weeks of age (Rawlings et al 1972, 1978, Secchiari et al 1976, Amann & Walker 1983.…”

Section: Introductionmentioning

confidence: 99%

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Postnatal changes in testicular gonadotropin receptors, serum gonadotropin, and testosterone concentrations and functional development of the testes in bulls

Bagu¹,

Cook²,

Gratton³

et al. 2006

Reproduction

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The primary objectives of this study were to follow the temporal patterns of testicular LH and FSH receptor (LH-R and FSH-R) concentrations and affinity (K a ) during sexual maturation in bulls and to see if such patterns could help explain the control of rapid testicular growth that occurs after 25 weeks of age, when serum gonadotropin concentrations are low. Separate groups of Hereford!Charolais calves (nZ6) were castrated every 4 weeks from 5 to 33 weeks of age and at 56 weeks of age. A week prior to castrations, from 5 to 33 weeks of age, blood was collected every 15 min for 10 h. The transition from indifferent supporting cells to Sertoli cells in seminiferous tubules was rapid between 13 and 25 weeks and rapid testis growth occurred after 25 weeks of age. Serum LH and FSH concentrations were transiently elevated at 12 weeks of age (P!0.05). LH-R concentrations decreased from 13 to 25 weeks of age and increased to 56 weeks of age (P!0.05). LH-RK a decreased from 9 to 17 weeks of age, increased to 29 weeks of age and declined to 33 weeks of age (P!0.05). FSH-R concentrations declined from 17 to 25 weeks of age then increased to 56 weeks of age (P!0.05). FSH-RK a increased from 17 to 25 weeks of age (P!0.05). High concentrations of gonadotropins and their receptors may be critical to initiate testis growth postnatally and support it after 25 weeks of age in the face of low serum gonadotropin concentrations.

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Section: Discussionsupporting

confidence: 57%

Section: Discussionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

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Postnatal changes in testicular gonadotropin receptors, serum gonadotropin, and testosterone concentrations and functional development of the testes in bulls

Bagu¹,

Cook²,

Gratton³

et al. 2006

Reproduction

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“…3) although they are presumably present during the whole lifespan (Katongole, Naftolin et Short 1971 ;Smith et al, 1973 ;Thibier, 1975 There is general agreement concerning the pattern of plasma testosterone which increases roughly from birth to the first year of age with a faster increment after 6 months of age (Rawlings et al,1972 ;Secchiari et al, 1976 fig. 1b).…”

mentioning

confidence: 88%

“…Thus plasma LH is said not to vary between the third and twelfth months of age (Odell, Hescox and Kiddy, 1970 ;Karg et a/., 1976) to increase between the first and seventh months (Mori et al, 1974) or to increase from seven months of age to adulthood (Gombe et al,1973). Similarly although plasma testosterone was found to increase with age, this increase was said to be erratic (Rawlings, Hafs and Swanson, 1972) or multiphasic (Secchiari et al, 1976).…”

mentioning

confidence: 99%

Temporal fluctuations of plasma LH and testosterone in Charolais bull calves during the first year of life

Lacroix¹,

Garnier²,

Pelletier³

et al. 1977

Ann. Biol. anim. Bioch. Biophys.

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Some of these discrepancies could be due in part to a pulsatile pattern of relaese which has been described for LH both in adult (Katongole, Naftolin and Short, 1971) and young bulls (Gombe et al., 1973 ;Thibier, 1975). They could arise also from insufficient blood samplings or number of animals studied.This confusing situation in the bull contrasts with our knowledge in the sheep in which the prepubertal period is associated with a pulsatile pattern of LH followed by a decrease in the level after puberty, whereas testosterone increases linearly (Foster, 1974 ;Courot, de Reviers and Pelletier, 1975).Thus, in an attempt to clarify the endocrine changes around puberty the concurrent patterns of plasma LH and testosterone were followed in Charolais calves from birth till one year of age.

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Temporal Variations of LH and Testosterone in Arabian Oryx (Oryx leucoryx) from Birth to Adulthood

Ancrenaz¹,

Blanvillain²,

Delhomme³

et al. 1998

General and Comparative Endocrinology

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Variation of Plasma Testosterone in Developing Friesian Bulls

Cited by 54 publications

References 12 publications

Postnatal changes in testicular gonadotropin receptors, serum gonadotropin, and testosterone concentrations and functional development of the testes in bulls

Postnatal changes in testicular gonadotropin receptors, serum gonadotropin, and testosterone concentrations and functional development of the testes in bulls

Temporal fluctuations of plasma LH and testosterone in Charolais bull calves during the first year of life

Temporal Variations of LH and Testosterone in Arabian Oryx (Oryx leucoryx) from Birth to Adulthood

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