TY - JOUR
T1 - Caspase-3 and caspase-activated deoxyribonuclease are associated with testicular germ cell apoptosis resulting from reduced intratesticular testosterone
AU - Kim, Jong Min
AU - Ghosh, Shampa R.
AU - Weil, Alexander C.P.
AU - Zirkin, Barry R.
PY - 2001
Y1 - 2001
N2 - The purpose of the present study was to examine the possible involvement of caspase-3 and caspase-activated deoxyribonuclease in rat testicular germ cell apoptosis resulting from reduced intratesticular testosterone concentration. Adult Sprague Dawley rats received LH-suppressive testosterone-and estradiol-filled SILASTIC capsules of 2.5 and 0.1 cm, respectively, a regimen known to rapidly reduce testosterone production by the testes and to produce azoospermia within 8 wk. Germ cell internucleosomal DNA cleavage increased compared with control levels by 1 wk postimplantation and increased further through 4 wk. In situ terminal deoxynucleotidyltransferase-mediated deoxy-UTP nick end labeling revealed that spermatocytes represented the predominant apoptotic cell type. Modest immunoreactivity for active caspase-3 was localized to the cytoplasm or perinuclear region of the germ cells of control testes. After testosterone and estradiol administration, however, intense staining for caspase-3 was localized to the nuclei of spermatocytes. Western blotting revealed significantly increased caspase-3 cleavage (activation) in nuclei isolated from germ cells after rats were administered testosterone and estradiol. Cleavage of the caspase-3 substrate protein, poly(ADP-ribose) polymerase, was seen after testosterone and estradiol treatment. Additionally, the caspase-activated deoxyribonuclease protein content was significantly increased in germ cells after rats were administered testosterone and estradiol, and caspase-activated deoxyribonuclease immunoreactivity was localized to the nuclei of apoptotic spermatocytes. Taken together, these results indicate that germ cell apoptosis resulting from a reduced intratesticular testosterone concentration is caspase-3 activation dependent and suggest that the translocation of active caspase-3 and caspase-activated deoxyribonuclease to the nucleus may be involved in the induction of germ cell apoptosis.
AB - The purpose of the present study was to examine the possible involvement of caspase-3 and caspase-activated deoxyribonuclease in rat testicular germ cell apoptosis resulting from reduced intratesticular testosterone concentration. Adult Sprague Dawley rats received LH-suppressive testosterone-and estradiol-filled SILASTIC capsules of 2.5 and 0.1 cm, respectively, a regimen known to rapidly reduce testosterone production by the testes and to produce azoospermia within 8 wk. Germ cell internucleosomal DNA cleavage increased compared with control levels by 1 wk postimplantation and increased further through 4 wk. In situ terminal deoxynucleotidyltransferase-mediated deoxy-UTP nick end labeling revealed that spermatocytes represented the predominant apoptotic cell type. Modest immunoreactivity for active caspase-3 was localized to the cytoplasm or perinuclear region of the germ cells of control testes. After testosterone and estradiol administration, however, intense staining for caspase-3 was localized to the nuclei of spermatocytes. Western blotting revealed significantly increased caspase-3 cleavage (activation) in nuclei isolated from germ cells after rats were administered testosterone and estradiol. Cleavage of the caspase-3 substrate protein, poly(ADP-ribose) polymerase, was seen after testosterone and estradiol treatment. Additionally, the caspase-activated deoxyribonuclease protein content was significantly increased in germ cells after rats were administered testosterone and estradiol, and caspase-activated deoxyribonuclease immunoreactivity was localized to the nuclei of apoptotic spermatocytes. Taken together, these results indicate that germ cell apoptosis resulting from a reduced intratesticular testosterone concentration is caspase-3 activation dependent and suggest that the translocation of active caspase-3 and caspase-activated deoxyribonuclease to the nucleus may be involved in the induction of germ cell apoptosis.
UR - http://www.scopus.com/inward/record.url?scp=0034870174&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034870174&partnerID=8YFLogxK
U2 - 10.1210/endo.142.9.8375
DO - 10.1210/endo.142.9.8375
M3 - Article
C2 - 11517157
AN - SCOPUS:0034870174
SN - 0013-7227
VL - 142
SP - 3809
EP - 3816
JO - Endocrinology
JF - Endocrinology
IS - 9
ER -