J. Noguchi et al., AGE-RELATED-CHANGES IN BLOOD-CONCENTRATIONS OF FSH, LH AND TESTOSTERONE AND TESTICULAR MORPHOLOGY IN A NEW RAT STERILE MUTANT WITH HEREDITARY ASPERMIA, Journal of Reproduction and Fertility, 97(2), 1993, pp. 433-439
A new rat mutant showing aspermia was investigated. Groups of 4-7 muta
nt male rats were killed at 3, 5, 10, 15 and 25 weeks of age. Examinat
ion by microscope showed apparent abnormalities in the seminiferous ep
ithelium from 3 weeks of age onward. Inclusion-like bodies were observ
ed in the cytoplasm of pachytene spermatocytes from 3 weeks old and in
stead of spermiation, polynuclear giant cells were formed within the s
eminiferous epithelium after 5 weeks of age. Histological analysis of
seminiferous epithelium of adult mutant rats also showed a marked decr
ease in the number of preleptotene, leptotene and pachytene spermatocy
tes and tubules containing only spermatogonia and Sertoli cells in the
seminiferous epithelium increased with age. However, the combination
of other cellular elements of germ cells in the seminiferous epitheliu
m was similar to that in normal rats and the distribution rate of thes
e seminiferous tubules was close to that of normal rats, indicating th
at cyclicity of seminiferous epithelium was still maintained in the mu
tant rats despite the lack of spermiation. Plasma concentrations of FS
H and LH were significantly higher in the mutant male rats than in nor
mal male rats at 5 and 10 weeks of age onward, respectively. Plasma co
ncentrations of testosterone were lower in the mutant male rats than i
n normal male rats. Silastic capsules containing testosterone were imp
lanted into the unilateral testis of adult mutant male rats and animal
s were autopsied 5 weeks later. However, intratesticular administratio
n of testosterone did not affect restoration of spermatogenesis. These
results indicate that the arrest of spermatogenesis had occurred from
the first cycle of spermatogenesis and the primary defect in the muta
nt is not gonadotrophin and testosterone deficiency.