title: Morphological studies on the origin of adult-type Leydig cells in rat testis.
abstract: The differentiation of adult-type Leydig cells (ATLC) in rat testis was studied with the help of electron microscopy and a combined technique of autoradiography and enzymehistochemistry. Male Wistar rats on each alternative day from postnatal day (pnd) 9 to 25 were perfused in situ, and the testicular sections were observed by electron microscopy. The cytoplasm of the ATLC contained smooth endoplasmic reticulum, mitochondria, a few small lipid droplets and a large well developed Golgi apparatus. In addition to typical fibroblasts/fibrocytes, a group of fibroblast-like cells was observed in the peritubular and perivascular spaces of the interstitial tissue. These cells, containing smooth endoplasmic reticulum and a large number of mitochondria with tubular-type cristae, were named as intermediate-type cells. In the autoradiographic experiments the 3-H-thymidine and 14-C-thymidine uptake behaviour of fetal-type Leydig cells, ATLC, intermediate-type cells and myoid cells was studied from 1 till 25 pnd. The intermediate-type cell, observed predominantly between pnd 9 to 21, showed the highest labelling index. The absolute number of fibroblasts/fibrocytes showed a peak on pnd 13 and decreased gradually with age. The duration of DNA synthesis phase ranged for interstitial fibroblasts: 7.9 h, for intermediate-type cell 10.4 h, for ATLC 17.4 h. The results lead to the conclusion that ATLC most probably originate to a large extent from the peritubular and to a lesser extent from perivascular fibroblast-like cells of the interstitial tissue.
authors.affiliation: Institute of Anatomy II, Heinrich Heine University Düsseldorf, Germany.
authors.forename: S G
authors.initials: SG
authors.lastname: Haider
authors.forename: D
authors.initials: D
authors.lastname: Laue
authors.forename: G
authors.initials: G
authors.lastname: Schwochau
authors.forename: B
authors.initials: B
authors.lastname: Hilscher
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D007985:Leydig Cells / Q000378:metabolism / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D017208:Rats, Wistar; D016196:S Phase / Q000502:physiology; D013234:Stem Cells / Q000378:metabolism / Q000648:ultrastructure; D013737:Testis / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure*