H. Merchantlarios et al., THE ROLE OF THE MESONEPHROS IN CELL-DIFFERENTIATION AND MORPHOGENESISOF THE MOUSE FETAL TESTIS, The International journal of developmental biology, 37(3), 1993, pp. 407-415
In mouse fetal gonads, the adjacent mesonephros is required for semini
ferous cord formation in vitro (Buehr et al., Development 117: 273-281
,1993). Here, we have investigated the role of mesonephric cells in se
miniferous cord formation and in differentiation of Sertoli and Leydig
cells. Undifferentiated male gonads with and without mesonephros at 1
1.5 dpc were cultured and immunocytochemical staining of Mullerian-inh
ibiting substance (MIS) was used as the criterion for Sertoli cell dif
ferentiation. For Leydig cells, testosterone (T) radioimmunoassay and
cytochemical detection of DELTA5-3beta-hydroxysteroid-dehidrogenase (H
SD) were undertaken. An ultrastructural study was also performed. In o
ur culture conditions, the timing of differentiation of both Sertoli a
nd Leydig cells was similar to that in the fetus. Although mesonephros
is required for seminiferous cord formation, differentiation of Serto
li and Leydig cells proceeds in its absence at 11.5 dpc. Moreover, whe
n 3H-thymidine labeled mesonephroi were grafted to unlabeled gonads, e
ndothelial and peritubular myoid-like cells migrated into the gonad. W
e propose that these cells might be the mesonephric cells required for
seminiferous cord formation.