Age-related changes in the function of the pituitary-gonadal axis in a sterile male rat mutant (hd/hd)
Testicular growth is depressed in the genetically sterile male rat (hd/hd) relative to its LE phenotype littermates (by 50% and 73% at 27 and 90 days of age, respectively). Within the hd/hd testis, both the tubular and seminiferous tubule tissues are affected by the mutation. In addition, there is s...
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Veröffentlicht in: | Biology of reproduction 1991-07, Vol.45 (1), p.11-19 |
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Zusammenfassung: | Testicular growth is depressed in the genetically sterile male rat (hd/hd) relative to its LE phenotype littermates (by 50%
and 73% at 27 and 90 days of age, respectively). Within the hd/hd testis, both the tubular and seminiferous tubule tissues
are affected by the mutation. In addition, there is significantly less germ cell production from the primary spermatocyte
stage of spermatogenesis onwards and the total number of Sertoli cells observed is less. In the intertubular tissue, the total
volume and the total number of Leydig cells per testis is significantly less, but the mean volume of an average Leydig cell
is not modified. The serum gonadotropin levels are higher in the hd/hd rat, whereas from 40 days of age onwards the level
of testosterone is lower. The FSH and LH binding affinity constants are unchanged by the mutation; however, the total number
of FSH binding sites per 10(6) Sertoli cells is lower while that of LH per 10(6) Leydig cells is greater. Indeed, it is likely
that the lesser concentration of serum testosterone in the hd/hd rat is a result of a smaller number of Leydig cells since
their individual function is not modified. The testicular androgen binding protein (ABP) content and the ABP output towards
the epididymis are lower as a consequence of both a lesser number and an altered function of the Sertoli cells. |
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ISSN: | 0006-3363 1529-7268 |
DOI: | 10.1095/biolreprod45.1.11 |