[Studies on endocrine and spermiogenic testis function. IV. Relations between the testosterone content of the testes cell nucleus volume of the Leydig cells and rat spermatogenesis (deduced from studies on the effect of the dietary protein quality on the function of the testes)].

The following relations were derived from large-scale testing of feed protein quality and its bearings on testicular function in growing Wistar rats: testicle weights and live weights r = 0.77 for juvenile animals and r = 0.36 for adult animals; nuclear volumes of Leydig's cells to testicle weights r = 0.84 for juvenile animals and r = 0.43 for adult animals; testosterone in testicular tissue, ng/g, to testicle weights r = 0.55 for juvenile animals and r = 0.80 for adult animals; testosterone per live weight, ng/100 g, to nuclear volumes of Leydig's cells r = 0.76 for juvenile animals and r = 0.46 for adult animals. Critical thresholds above which complete spermatogenesis is always ensured may be established for testosterone (50+/-5 ng/100 g live weight) and for the nuclear volume of Leydig's cells (30 mum3). Another conclusions drawn from the above results is that high testosterone levels in the testes of adult animals were not attributable to high testosterone biogenesis of Leydig's cells, as might have been assumed from high activities of that kind recordable from some nuclear volumes.