Annals of Clinical Biochemistry DOI: The effect of testosterone, dihydrotestosterone and oestradiol on the re-initiation of spermatogenesis in the adult photoinhibited Djungarian hamster. Journal of Endocrinology. Endocrine aspects of sexual dysfunction in men. The Journal of Sexual Medicine 1: The myotubularin family of lipid phosphatases in disease and in spermatogenesis.
Biochemical Journal Endocrine testicular function in vivo and in vitro in infertile men. Acta Endocrinologica Copenhagen The Epididymis. Chapter Hormonal regulation of male germ cell development. Journal of Endocrinology Novel epididymal proteins as targets for the development of post-testicular male contraception. Reproduction PACAP-mediated sperm-cumulus cell interaction promotes fertilization.
Review: Androgens and spermatogenesis: lessons from transgenic mouse models.
Philosophical Transactions of the Royal Society B Walker WH. Non-classical actions of testosterone and spermatogenesis.
Cover for Knobil and Neill's Physiology of Reproduction. Knobil and Neill's Physiology of Reproduction. Book • 3rd Edition • Edited by: VOLUME 1. Purchase Knobil and Neill's Physiology of Reproduction - 3rd Edition. These volumes are clearly designed for students of reproductive physiology and cover.
Measurement of total serum testosterone in adult men: comparison of current laboratory methods versus liquid chromatography-tandem mass spectrometry. Androgen receptor roles in spermatogenesis and fertility: lessons from testicular cell-specific androgen receptor knockout mice.
Endocrine Review. Androgen receptor in Sertoli cells is not required for testosterone-induced suppression of spermatogenesis, but contributes to Sertoli cell organization in Utp14bjsd mice. Journal of Andrology Immunohistochemical demonstration of the intracellular localization of pituitary adenylate cyclase activating polypeptide-like immunoreactivity in the rat testis using the stamp preparation. Presence of lumen and germ cells in seminiferous tubules age testis weight increased fold Fig.
Even though Fig. Characteristics of tubular tissue empty, vacuole-like spaces began to appear in some tubules. Representative images during testis development in Blackbelly ram lambs.
At birth panel A and during the first weeks of age panel B seminiferous tubules were observed as solid cords, with Sertoli cells occupying most of the inner space, and their nuclei SC located at the periphery. A few gonocytes arrowheads were observed located in a central position panel A or migrating to the periphery panel B. At 12 weeks panel C , many primary spermatocytes PS and other meiotic figures, along with a central lumen L , were observed in most of the tubules. By Week 18 panel D elongated spermatids asterisks were observed in nearly all the tubules evaluated, indicating that spermatogenesis had been fully established.
Scale bar represents 25 mm panels A and B or 75 mm panels C and D. Elongated spermatogonia populations. M of total nuclear volume and Sertoli cell number, between birth and 21 weeks of age, in Blackbelly ram lambs Age group weeks No. Sertoli cell nuclear volume Number of Sertoli cells Individual Total per paired Per paired Per gram of Per gram of mm3 testes cm3 testes seminiferous tubule testicular parenchyma 0 6 Relative changes times, when values at birth are set to 1 in various characteristics of Sertoli cells in Blackbelly ram lambs between birth and 21 weeks of age.
Average and individual percentages of seminiferous tubules with a relative growth of fold during this period with lumen panel A , and with elongated spermatids panel B in Fig. Apparently, adult Sertoli cell population was established around 15 weeks of age, since no more changes in Sertoli cell number were detected afterward time at 15 weeks of age Fig. By Weeks 18 and 21 Figs. The total Fig. Development of Sertoli cell number average and individual volume occupied by Sertoli nuclei increased steadily in Blackbelly ram lambs between birth and 21 weeks of age. Data were as the ram lambs were older, from birth to 21 weeks logn transformed before the statistical analysis and back-transformed for presentation.
Closed cir- small two-fold , as compared with the relative cles indicate ages when Sertoli cell number ceased increasing.
Sertoli cell number per gram of tissue decreased as the ram lambs were older Table 2. Sertoli number per gram of tubular tissue was the greatest at birth and at 3 weeks of age, thereafter decreased until Week 12; the most remarkable decline was between 9 and 12 weeks of age Fig. Note that at some time points, symbol size is larger than the S. The molar ratio of T3 and T4 per gram of testicular parenchyma did not change Fig. Concentrations of LH Fig. Testosterone and 1.
Discussion Fig. The increase in LH concentration indicates that a change in age at which Sertoli cell number stabilized agreed with the sensitivity of the hypothalamus-pituitary-testicular data for other breeds, such as Ile-de-France, and with axis occurs at that time, perhaps representing the time previous observations that Sertoli cells cultured in vitro of initiation of the pubertal process . Serum LH maintain the ability of incorporating [3H]thymidine at concentrations at early ages are greater in early- than 12 weeks of age , but was greater than the age late-maturing rams ; furthermore, the timing of reported for crossbred Romanov ram lambs [13,14].
LH increase after birth seems to be related to the The fold increase in cell number between birth and prolificacy of the breed, more prolific breed present an Week 21 represented about 4. Apparently, the increased secretion and accumulation of tubular proliferation rate of Sertoli cells decreases after birth, fluid produced by Sertoli cells, which is part of the since during the fetal life there are at least eight cycles functional maturation process of the seminiferous of cell duplication between sex differentiation 42 days epithelium, and the formation of tight junctions and birth, with six cycles occurring before days of between adjacent Sertoli cells .
As Sertoli cells fetal life . During the first weeks after formation of the blood-testis barrier  and the birth, gonocytes and spermatogonia were the only germ appearance of the first pachytene spermatocytes . In cells associated with Sertoli cells , as the sperma- the present study, pachytene spermatocytes were togonia remained close to the basal membrane and no observed in most tubules at 12 weeks of age, earlier more advanced germ cells were present, the tubule than the age when Sertoli cell number remained elongation occurring during this period largely resulted constant 15 weeks.
This apparent discrepancy can from spermatogonia and Sertoli cell mitotic activity be explained based on previous reports in rats; the .
However, when spermatogenesis began, other beginning of meiotic maturation during the first germ cell types appeared and started proliferating, spermatogenic wave seemed to be independent of the which were the primary responsible for the increase in appearance of the blood-testis barrier . Further- tubule diameter . Once Sertoli cells ceased more, Sertoli cells maintained a lower rate of proliferating, the increase in tubular tissue was largely proliferation after the beginning of formation of the a consequence of enhanced proliferation activity and barrier . An alternative explanation is that our differentiation of germs cells.
The presence of meiotic sampling design did not allow us to precisely determine figures at 12 weeks of age indicated that spermatogen- when Sertoli cells ceased proliferating, since we could esis had already started at that age, whereas the presence not monitor more closely the different events occurring of elongated spermatids in the seminiferous epithelium during the period of most rapid testicular growth i.
In that regard, proliferation of both, During the period of rapid testis growth, there was spermatogonia and Sertoli cells, is considered the also a significant increase in T concentration as a primary determinant of the increase of the seminiferous consequence of increased testicular response to LH, epithelium volume at that age. The relative decrease of which was in agreement with the role of T in advanced Sertoli cell number per volume unit of testis tissue, stages of spermatogenesis, that is, in the completion of observed from Weeks 9 and 12, indicated a greater meiosis and the initiation and maintenance of all growth rate of other components of the testicular tissue, phases of spermiogenesis [26,27].
The early increase at both levels, including inside the seminiferous tubules, in mean LH concentration 6 weeks of age has as a consequence of the establishment of spermatogen- previously been reported for other breeds [28—30], and esis, as well as in the interstitial tissue Leydig cells, reflects an increase in LH pulse frequency .
This connective tissue and blood and lymphatic vessels. Morales and release of sperm into the tubule lumen. Neurobiology, UNAM , Pablo Pacheco, Mayvi Alvar- Due to limited reports in literature, it is difficult to ado and Roberto Ortiz Institute of Neuroethology, make an extensive comparison, regarding the develop- University of Veracruz for technical assistance with ment of the different components of the testicular tissue, image processing.
However, in the graduate student, under the supervision of the last present study, the age when spermatids were observed author HJS. Restoration lambs from various wool breeds [37,38], which is in of spermatogenesis in infertile mice by Sertoli cell transplanta- agreement with previous reports indicating that St.
Biol Reprod ;— Cytology of the testis and intrinsic control mechanisms. In: Neill JD, than Rambouillet ram lambs. The number of Sertoli maturation of Sertoli cells and advance the age at which cells in mature Holstein bulls and their relationship to quanti- proliferation capacity is lost . Furthermore, in tative aspects of spermatogenesis. Biol Reprod ;—7. The central role of Sertoli cells in spermatogen- developing rats, T3 induces maturation of seminiferous esis.
Semin Cell Dev Biol ;—6. Proliferation and increased tubule diameter [10,11], these effects are functional maturation of Sertoli cells, and their relevance to mediated by specific receptors type TRa1, located in disorders of testis function in adulthood.
J Reprod Fertil Sertoli cells during the period of proliferation [11,41]. The Sertoli cell. In: Neill JD, editor. The present study tried to find a temporal relationship 3rd ed. The only Prespermatogenesis and spermatogoniogenesis in the bovine testis. Anat Embryol ;— Neonatal administration of FSH the biologically active hormone , this change might increases Sertoli cell numbers and spermatogenesis in gonado- be of physiological importance in terms of testis tropin-deficient hpg mice.
J Endocrinol ;— Ram lambs need germ cells intermediate spermatogonia and pachytene FSH for normal testicular growth, Sertoli cell number and onset spermatocytes have TRa1 receptors . Reprod Nutr Dev ;— High In conclusion, Sertoli cells maintained a substantial neonatal triiodothyronine levels reduce the period of Sertoli cell rate of proliferation between birth and 15 weeks of age proliferation and accelerate tubular lumen formation in the rat in Blackbelly sheep. In these ram lambs, the process of testis, and increase serum inhibin levels.
Endocrinology puberty began early in life, and the period of accelerated ;— Regulation of neonatal Sertoli cell development by thyroid hormone receptor changes in testicular tissue, as a consequence of the a1. Thyroid hormone reg- maturation of Sertoli cells. Sertoli cell biology.
Varia- — J Reprod Fertil ;— Keogh EJ. Sperma- birth to sexual maturity. J Reprod Fertil ;—6. J Reprod Fertil ;Suppl. Ontogeny of pulsatile luteinizing hormone and Martin MT. Efficiency of spermatogenesis in animals and humans. Effects of experimental cryptorchid- ram lambs. J Anim Sci ;— J Androl ;— Basic neuroendocrine hormone agonist. Histological ;Suppl. Sertoli cell barrier, tubular lumen, and cytoskeleton of Sertoli  Abercrombie M. Estimation of nuclear population from micro- and myoid cells in the rat, and their relationship to tubular fluid tome sections.