Male Sexual Development

Colenbrander, B.; Frankenhuis, M. T.; Wensing, C. J. G.

doi:10.1016/b978-0-408-10768-6.50006-x

Cited by 25 publications

(14 citation statements)

References 52 publications

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“…The timing of appearance of spermatocytes or spermatozoa in the xenografts was similar to those observed in developing boars [33,34]. Zeng et al [35] demonstrated that the length of the spematogenic cycle in porcine xenografts implanted into immunodeficient mice was about 9 days, which is similar to that observed in boars [33,36].…”

Section: Discussionsupporting

confidence: 65%

“…This probably explains the decrease in circulating inhibin levels as sexual maturation approaches. In our host mice, lumens formed in the seminiferous tubules of the subcutaneous grafted tissues from day 90, and the inhibin level per Sertoli cell was estimated to be in decline with differentiation of seminiferous tubules as in normal boars [18,33]. However, as a matter of course, the tubules lacked efferent ducts.…”

Section: Inhibin and Fsh In Host Mousementioning

confidence: 93%

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Endocrine Status and Development of Porcine Testicular Tissues in Host Mice

Kaneko

Kikuchi

Nakai

et al. 2008

Journal of Reproduction and Development

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Abstract. Clarification of the endocrine status of host mice provides us with basic knowledge with which we can manipulate the growth and function of xenografted testicular tissues. We investigated the hormonal profiles of castrated mice grafted with porcine immature testicular tissues from 30 to 210 or more days after grafting (day 0= castration and grafting). The serum follicle stimulating hormone (FSH) concentrations of the host mice declined (P<0.05) from day 60 compared with those of the castrated, ungrafted mice. The serum inhibin and testosterone levels were higher (P<0.05) than those in the castrated, ungrafted mice from days 30 and 90 days, respectively. The inhibin levels further increased (P<0.05) from day 90, during which time the levels were higher (P<0.05) than those in the intact male mice. In the grafts, formation of lumens occurred in the seminiferous cords on day 90 and spermatozoa appeared in the lumens from day 120. However, spermatogenesis in the grafts did not reach the qualitatively normal levels observed in adult boars. The intensity of the immune reaction to inhibin α subunits in the Sertoli cells of the grafts decreased with differentiation of the seminiferous tubules. The present findings indicate that a feedback loop was established between the mouse hypothalamo-pituitary axis and the grafted porcine tissues from 60 days post-grafting. The results also indicate that the serum inhibin levels in the host mice remained high even after the appearance of lumens in the seminiferous tubules of the grafted tissues; this is strikingly different to the situation in normal male animals, in which the serum inhibin levels decline at around the time of tubular differentiation. The lack of efferent ducts in the tubules of the grafted tissues probably caused the accumulation of inhibin to be released into the lumens, resulting in high concentrations of circulating inhibin. These high levels of inhibin may directly affect spermatogenic activity and suppress FSH secretion. [6], and then xenografted into immunodeficient mice. Successful recovery of spermatozoa from the grafts has been proven in several species (pigs [3], cats [5] and rhesus monkeys [6]). However, no progeny have been obtained from spermatozoa isolated from the xenografts of these animals. Clarification of the endocrine status of the host mouse would likely help us to improve spermatogenesis in grafted testicular tissues, since development of the testis is controlled by the balance between the pituitary hormones, which stimulate testicular function, and testicular hormones, which alter the secretion of the pituitary hormones [7]. To date, the hormonal characteristics of host mice have been elucidated only after grafting of murine testicular tissues [8]; the study indicated that a feedback loop was established between the graft and the host's hypothalamo-pituitary 2 weeks after grafting, when the graft acquired the ability to produce testosterone. However, the time required for testicular maturation is much longer in large animals, such ...

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Section: Discussionsupporting

confidence: 65%

Section: Inhibin and Fsh In Host Mousementioning

confidence: 93%

Endocrine Status and Development of Porcine Testicular Tissues in Host Mice

Kaneko

Kikuchi

Nakai

et al. 2008

Journal of Reproduction and Development

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“…However, observations that testosterone will fully restore spermatogenesis in mature rats after active immunization against GnRH [26] but will not do so after regression of the testes following hypophysectomy [27] suggest that pituitary hormones other than FSH may be involved in these complex processes. Peripheral concentrations of LH, FSH, TSH, PRL, and GH are all at peak levels within the first 2 wk of life in the boar, potentially interacting with a high secretory level of testosterone [17,28].…”

Section: Discussionmentioning

confidence: 98%

Diverse Testicular Responses to Exogenous Growth Hormone and Follicle-Stimulating Hormone in Prepubertal Boars1

Swanlund

N’Diaye

Loseth

et al. 1995

Biology of Reproduction

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The effects of exogenous growth hormone (GH) and FSH on development of the testes in intact prepubertal boars was investigated. Twenty-four boars received one of four daily treatments from 8 through 40 days of age: 1) 90 micrograms porcine (p) GH/kg body weight (BW), 2) 100 micrograms pFSH/kg BW, 3) GH + FSH, or 4) vehicle only (control). Plasma testosterone levels, measured at 10-day intervals, were similar among groups of boars throughout the study. Body weights among groups were similar during treatment, and testicular weight between treatment groups did not differ at castration (100 days of age). However, total length of the seminiferous tubule per testis in FSH-treated boars was 59% greater than in GH-treated animals (2705 vs. 1704 m; p < 0.05). Diameter of the tubule in GH-treated boars was 58% greater than in FSH-treated boars (p = 0.03). Relative mass of spermatocytes and spermatids in GH-treated animals exceeded that in controls by 2.5-fold and that in FSH boars by 75-fold (p = 0.05). There were no differences in effects of GH + FSH treatment as compared to control treatment; none of the treatments affected any interstitial tissue parameter measured. These results suggest that exogenous FSH had a mitogenic effect on Sertoli cells while delaying tubular maturity, whereas exogenous GH promoted tubular and Sertoli cell maturation, defined as increased Sertoli cell size, lumen formation, and onset of spermatogenesis.

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“…All boars were Large White × Landrace crossbreeds produced at the National Institute of Livestock and Grassland Science, Tsukuba, Japan. In European breeds, the bloodtestis barrier is formed at about 14 to 17 weeks and s p e r m a t o g e n e s i s i s c o m p l e t e d i n m a n y seminiferous tubules at about 20 weeks [8]. To isolate and characterize F-spondin in the testis, 100 g wet weight of testis tissue was collected from fifty 8-week-old boars.…”

Section: Samplesmentioning

confidence: 99%

Isolation and Identification of F-Spondin in the Boar Testis and Its Production During Testis Growth

Ohnuma

Kaneko

Noguchi

et al. 2007

Journal of Reproduction and Development

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Abstract. F-spondin/vascular smooth muscle cell growth-promoting factor (VSGP), purified from the follicular fluid of adult bovine ovaries, has been identified as a promoter of neuronal differentiation and vascular smooth muscle growth. The objectives of the present study were (1) to clarify whether Fspondin is also produced in the testis, which is ontogenically equivalent to the ovary, and (2) to examine whether production of this protein changes with testicular growth. To isolate F-spondin from the testis, testicular homogenates obtained from 8-week-old boars were sequentially subjected to heparin-Sepharose chromatography, diethylaminoethyl (DEAE)-Sepharose chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). The isolated protein had a molecular mass of approximately 110 kDa and was cross-reactive with anti-F-spondin antibody by Western blotting. The purified protein was further characterized by amino acid sequence analysis of its internal peptide. The sequence obtained was GEQCNIVPDN VD, and a homology search indicated that the purified protein is a homologue of rat, human, and bovine F-spondin. By fractionation of the same amounts of testis tissue obtained from 1-, 8-, 16-, and 40-week-old boars, we analyzed age-related production of F-spondin in the testis. Western blotting of the fractions obtained from RP-HPLC revealed the presence of a band at approximately 110 kDa, corresponding to Fspondin, in the testes obtained from boars between 1 and 16 weeks old, but this band was not detected at 40 weeks. These results clearly indicate that (1) the porcine testis produces F-spondin and that (2) production of this protein is evident in the immature porcine testis, but not the adult testis.

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Male Sexual Development

Cited by 25 publications

References 52 publications

Endocrine Status and Development of Porcine Testicular Tissues in Host Mice

Endocrine Status and Development of Porcine Testicular Tissues in Host Mice

Diverse Testicular Responses to Exogenous Growth Hormone and Follicle-Stimulating Hormone in Prepubertal Boars1

Isolation and Identification of F-Spondin in the Boar Testis and Its Production During Testis Growth

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