Dynamics of Testicular Germ Cell Proliferation in Normal Mice and Transgenic Mice Overexpressing Rat Androgen-Binding Protein: A Flow Cytometric Evaluation
Transgenic mice carrying rat androgen-binding protein (ABP) genomic DNA express high amounts of testicular ABP and develop a progressive impairment of spermatogenesis. To understand the mechanism of these changes, we have studied the pattern of testicular germ cell proliferation from 7 to 360 days o...
Saved in:
Published in | Biology of reproduction Vol. 66; no. 4; pp. 877 - 885 |
---|---|
Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Madison, WI
Society for the Study of Reproduction
01.04.2002
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Transgenic mice carrying rat androgen-binding protein (ABP) genomic DNA express high amounts of testicular ABP and develop
a progressive impairment of spermatogenesis. To understand the mechanism of these changes, we have studied the pattern of
testicular germ cell proliferation from 7 to 360 days of age in wild-type (WT) control and transgenic homozygous (ABP-TG)
mice by flow cytometry after labeling DNA in isolated germ cells with propidium iodide. At all ages studied, the body weight
of the ABP-TG mice was lower than that of age-matched WT controls. Significantly reduced testicular weight and total germ
cell number in the ABP-TG mice were evident from Day 30 and Day 60, respectively. Flow cytometric analysis of isolated germ
cells revealed that the number of germ cells undergoing proliferation (S-phase cells) was identical in WT control and ABP-TG
mice up to Day 14. Subsequently, the number of germ cells in S-phase was consistently higher in ABP-TG than in WT mice. The
number of primary spermatocytes was significantly increased starting from Day 60, and the numbers of round and elongated spermatids
were significantly reduced in the ABP-TG animals from Day 21 and Day 60 onwards, respectively. Immunocytometry for intracellular
ABP at 90 days of age revealed that the percentage of ABP-containing germ cells was greater in ABP-TG than in WT mice. The
continuous presence of ABP in mouse seminiferous tubules at greater than physiological concentrations facilitates the formation
of primary spermatocytes but impairs subsequent transformation to round and elongated spermatids. Based on our observations
and the analysis of the available literature, the most likely mechanism for production of these effects is sustained reduction
in the bioavailability of androgens. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0006-3363 1529-7268 |
DOI: | 10.1095/biolreprod66.4.877 |