during the first weeks of life ≈5 days: in adults 12.8 days
||Rat Rattus norvegicus
||de Rooij DG, Russell LD. All you wanted to know about spermatogonia but were afraid to ask. J Androl. 2000 Nov-Dec21(6):776-98 p.782 left column bottom paragraphPubMed ID11105904
||van Haaster LH, de Rooij DG. Spermatogenesis is accelerated in the immature Djungarian and Chinese hamster and rat. Biol Reprod. 1993b 49 :1229–1235 AND Hilscher B, Hilscher W, Maurer W. Autoradiographic studies on the modus of proliferation and regeneration of the seminiferous epithelium of Wistar rats [in German]. Z Zellforsch Mikrosk Anat. 1969 94: 593– 604.PubMed ID8286605, 5809191
||Primary source van Haaster LH, de Rooij DG. 1993b abstract: "The rate of progression of spermatogenesis was studied in immature Djungarian and Chinese hamsters and Wistar rats by scoring the most advanced cell types present at various ages after birth."
||P.782 left column bottom paragraph: "The epithelial cycle in young animals is much shorter than in adults (Kluin et al, 1982, primary source van Haaster and de Rooij, 1993b). In rats, the epithelial cycle takes about 5 days during the first weeks of life (primary source van Haaster and de Rooij, 1993b) versus 12.8 in adults (primary source Hilscher et al, 1969), in Chinese hamsters, the comparable figures are 9 days (primary source van Haaster and de Rooij, 1993b) versus 17 days in adults (Oud and de Rooij, 1977)."