Androgen receptor and calcitonin gene-related peptide in neurons of the genitofemoral nerve during testicular descent induced with human chorionic gonadotropin.
BACKGROUND
Low levels of circulating testosterone during testis descent cause cryptorchidism in humans and rats. Treatment with human chorionic gonadotrophin (hCG) induces testis descent by stimulating production of testosterone (T). Neurons of genitofemoral nerve (GFN), which innervate testicular gubernaculum, may play a role in testis descent.


METHODS
In the current study, putative correlations were made between T and GFN motor and sensory neuron activity during inguinoscrotal testis descent. Cryptorchidism was provoked in prepuberal rats with estradiol. Rats with testicular descent induced with hCG and cryptorchid controls were used. Cells of spinal cord and dorsal root ganglia were labeled by retrograde staining with fast-blue. Expression of androgen receptor (AR) and calcitonin gene-related peptide (CGRP) were detected with indirect immunofluorescence.


RESULTS
Neurons labeled with fast-blue were found in the center of motor horn and dorsal root ganglia at levels L1 and L2. While number of motor neurons expressing AR was significantly higher in the group treated with hCG, number expressing CGRP was higher in controls. In dorsal root ganglion, number of cells immunostained with CGRP antibody was similar in both groups but AR was not detected.


CONCLUSIONS
Present results support the hypothesis that motor nucleus of the GFN is a direct target of testosterone and that regulation of CGRP in sensory nucleus may be involved in testicular descent.
Vigueras
Rosa María
RM
Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico.
Moreno-Mendoza
Norma
N
Reyes
Gabriela
G
Merchant-Larios
Horacio
H
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003456:Cryptorchidism; D004958:Estradiol / Q000378:metabolism; D006801:Humans; D008297:Male; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011944:Receptors, Androgen / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology; D013737:Testis / Q000294:innervation / Q000502:physiology; D013739:Testosterone / Q000378:metabolism
D006063:Chorionic Gonadotropin; D011944:Receptors, Androgen; D013739:Testosterone; D004958:Estradiol; D015740:Calcitonin Gene-Related Peptide