Delayed testicular aging in pituitary adenylate cyclase-activating peptide (PACAP) null mice.
Age-related decline in male sex hormones is a direct consequence of testicular aging. These changes in the hormonal complement cause physiological disturbances affecting the quality of life for millions of aging men. To assess the influence on testicular aging of pituitary adenylate cyclase-activating peptide (PACAP), a polypeptide that regulates testicular steroidogenesis in vitro, we compared the testicular structure and function between C57BL/6 wild-type and PACAP-/- male mice, at 4 and 15 months of age. We show that, in 4-month-old PACAP-/- mice, steroidogenesis (evaluated by levels of testosterone, steroidogenic acute regulatory protein, 3beta-hydroxysteroid dehydrogenase, and P450c17) was impaired. However, the testicular structure of these animals was not affected. At 15 months of age, wild-type testis displayed typical signs of aging (patchy seminiferous tubules, germ cell depletion, and vacuolization), whereas testicular structure was remarkably well conserved in PACAP-/- animals. The depletion of germ cells found in wild-type animals was associated with a higher content of peroxynitrites, a marker of reactive oxygen species, and a higher number of apoptotic cells compared with PACAP-/- mice. Our results show that testicular aging is delayed in PACAP-/- animals. Because the expression levels of steroidogenic factors are low and constant over time in knockout animals, a proposed mechanism for the protection against testicular degeneration is that production of reactive oxygen species, a byproduct of steroidogenesis that induces apoptosis, is down-regulated in PACAP-/- animals.
Lacombe
Arnaud
A
Department of Human Genetics, University of California, Gonda Center, 695 Charles Young Drive South, Los Angeles, CA 90095-7088, USA.
Lelievre
Vincent
V
Roselli
Charles E
CE
Salameh
Wael
W
Lue
Yan-he
YH
Lawson
Gregory
G
Muller
Jean-Marc
JM
Waschek
James A
JA
Vilain
Eric
E
D000375:Aging / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D007985:Leydig Cells / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000172:deficiency* / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D013254:Steroid 17-alpha-Hydroxylase / Q000378:metabolism; D013256:Steroids / Q000096:biosynthesis; D013737:Testis / Q000378:metabolism* / Q000473:pathology*; D000098682:Steroidogenic Acute Regulatory Protein
C495402:Adcyap1 protein, mouse; D018076:DNA, Complementary; D010750:Phosphoproteins; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D017382:Reactive Oxygen Species; D013256:Steroids; D000098682:Steroidogenic Acute Regulatory Protein; D013254:Steroid 17-alpha-Hydroxylase