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Morgan JT, Robbins AK, Mateson AB, Sawamoto K, Tomatsu S, Gray DR, Gleghorn JP, Barthold JS. Regional Variation in Androgen Receptor Expression and Biomechanical Properties May Contribute to Cryptorchidism Susceptibility in the LE/orl Rat. Front Endocrinol (Lausanne) 2018; 9:738. [PMID: 30568634 PMCID: PMC6290328 DOI: 10.3389/fendo.2018.00738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 11/20/2018] [Indexed: 11/13/2022] Open
Abstract
Background: The process of testicular descent requires androgen and insulin-like 3, hormones secreted by fetal Leydig cells. Knowledge concerning distinct and common functions of these hormones in regulating development of the fetal gubernaculum remains limited and/or conflicting. The current studies were designed to better define characteristics of androgen receptor (AR) expression, function and regulation, as well as the biomechanical properties of normal and cryptorchid gubernaculum during fetal development. Methods: We studied fetal gubernacula from Long Evans outbred (LE/wt) rats and an inbred (LE/orl) strain with an inherited form of cryptorchidism associated with an AR signaling defect. Gubernacular cells or whole organs obtained from LE/wt and LE/orl fetal gubernacula underwent AR immunostaining and quantitative image analysis. The effects of dihydrotestosterone (DHT) on AR expression, muscle fiber morphology, hyaluronan (HA) levels and glycosaminoglycan (GAG) content were measured in LE/wt gubernacula. Finally, the spatial mechanics of freshly harvested LE/wt and LE/orl fetal gubernacula were compared using micropipette aspiration. Results: AR is expressed in the nucleus of mesenchymal core, tip and cord cells of the embryonic (E) day 17 and 21 fetal gubernaculum, and is enhanced by DHT in primary cultures of gubernacular mesenchymal cells. Enhanced AR expression at the tip was observed in LE/wt but not LE/orl gubernacula. In in vitro studies of whole mount fetal gubernaculum, DHT did not alter muscle fiber morphology, HA content or GAG production. Progressive swelling with reduced cellular density of the LE/wt gubernaculum at E19-21 was associated with increased central stiffness in LE/wt but not in LE/orl fetuses. Conclusions: These data confirm nuclear AR expression in gubernacular mesenchyme with distal enhancement at the tip/cord region in LE/wt but not LE/orl rat fetuses. DHT enhanced cellular AR expression but had no major effects on muscle morphology or matrix composition in the rat fetal gubernaculum in vitro. Regional increased stiffness and decreased cell density between E19 and E21 were observed in LE/wt but not LE/orl fetal gubernacula. Developmental differences in cell-specific AR expression in LE/orl fetal gubernacula may contribute to the dysmorphism and aberrant function that underlies cryptorchidism susceptibility in this strain.
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Affiliation(s)
- Joshua T. Morgan
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
- *Correspondence: Joshua T. Morgan
| | - Alan K. Robbins
- Nemours Biomedical Research, Division of Urology, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Abigail B. Mateson
- Nemours Biomedical Research, Division of Urology, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Kazuki Sawamoto
- Department of Orthopedics, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Shunji Tomatsu
- Department of Orthopedics, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Dione R. Gray
- Nemours Biomedical Research, Division of Urology, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Jason P. Gleghorn
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Julia Spencer Barthold
- Nemours Biomedical Research, Division of Urology, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
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The area and attachment abnormalities of the gubernaculum in patients with undescended testes in comparison with those with retractile testes. Pediatr Surg Int 2014; 30:1149-54. [PMID: 25217140 DOI: 10.1007/s00383-014-3597-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/09/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE In order to evaluate the gubernaculum (GN) abnormalities quantitatively in patients with undescended testes (UDT), the area and attachment site of the gubernaculum were evaluated. PATIENTS AND METHODS Sixty-seven testes from 61 patients with an undescended testis treated in the past 11 years at our institution were examined. Using intraoperative photographs or DVDs, the area of the GN inside the processus vaginalis was measured, and the ratio to that of the testis was determined. When the GN was attached to the vas deferens, the GN distance from the testis was also measured, and the ratio to that of the transverse length of the testis (deviation index) was calculated. Reference values were obtained from 23 testes from 15 patients with mobile testes. RESULTS In cases with mobile testes, the GN attached to the bottom of the testis, and involved the lower pole of the epididymis. Even though the GN was attached to the bottom of the testis in 43 testes in the UDT patients (64 %), the GN was found to be elongated. The mean GN area ratio was 1.58 (1SD, 0.6) in the UDT cases, in comparison to 0.47 (0.2) in the cases with mobile testes. The GN was attached to the vas deferens in 24 testes (36 %). The deviation index was 1.34 (1.0), but the GN area ratio of these cases was 1.56 (0.7), which was similar to that of the GN attached to the bottom of the testis. CONCLUSION The present study revealed that an increase in the GN area ratio was the most common imaging abnormality in cases with UDT.
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Barthold JS, Robbins A, Wang Y, Pugarelli J, Mateson A, Anand-Ivell R, Ivell R, McCahan SM, Akins RE. Cryptorchidism in the orl rat is associated with muscle patterning defects in the fetal gubernaculum and altered hormonal signaling. Biol Reprod 2014; 91:41. [PMID: 24966393 DOI: 10.1095/biolreprod.114.119560] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cryptorchidism, or undescended testis, is a common male genital anomaly of unclear etiology. Hormonal stimulation of the developing fetal gubernaculum by testicular androgens and insulin-like 3 (INSL3) is required for testicular descent. In studies of the orl fetal rat, one of several reported strains with inherited cryptorchidism, we studied hormone levels, gene expression in intact and hormone-stimulated gubernaculum, and imaging of the developing cremaster muscle facilitated by a tissue clearing protocol to further characterize development of the orl gubernaculum. Abnormal localization of the inverted gubernaculum was visible soon after birth. In the orl fetus, testicular testosterone, gubernacular androgen-responsive transcript levels, and muscle-specific gene expression were reduced. However, the in vitro transcriptional response of the orl gubernaculum to androgen was largely comparable to wild type (wt). In contrast, increases in serum INSL3, gubernacular INSL3-responsive transcript levels, expression of the INSL3 receptor, Rxfp2, and the response of the orl gubernaculum to INSL3 in vitro all suggest enhanced activation of INSL3/RXFP2 signaling in the orl rat. However, DNA sequence analysis did not identify functional variants in orl Insl3. Finally, combined analysis of the present and previous studies of the orl transcriptome confirmed altered expression of muscle and cellular motility genes, and whole mount imaging revealed aberrant muscle pattern formation in the orl fetal gubernaculum. The nature and prevalence of developmental muscle defects in the orl gubernaculum are consistent with the cryptorchid phenotype in this strain. These data suggest impaired androgen and enhanced INSL3 signaling in the orl fetus accompanied by defective cremaster muscle development.
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Affiliation(s)
- Julia S Barthold
- Nemours Biomedical Research/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Alan Robbins
- Nemours Biomedical Research/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Yanping Wang
- Nemours Biomedical Research/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Joan Pugarelli
- Nemours Biomedical Research/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Abigail Mateson
- Nemours Biomedical Research/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Ravinder Anand-Ivell
- Division of Animal Sciences, University of Nottingham, Leicestershire, United Kingdom
| | - Richard Ivell
- Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany
| | - Suzanne M McCahan
- Nemours Biomedical Research/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Robert E Akins
- Nemours Biomedical Research/Alfred I. duPont Hospital for Children, Wilmington, Delaware
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Nation TR, Buraundi S, Balic A, Farmer PJ, Newgreen D, Southwell BR, Hutson JM. The effect of flutamide on expression of androgen and estrogen receptors in the gubernaculum and surrounding structures during testicular descent. J Pediatr Surg 2011; 46:2358-62. [PMID: 22152882 DOI: 10.1016/j.jpedsurg.2011.09.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 09/03/2011] [Indexed: 11/16/2022]
Abstract
BACKGROUND/PURPOSE Inguinoscrotal testicular descent is controlled by androgens between embryonic days E16-19, but androgen receptor (AR) and estrogen receptor (ER) locations are unknown. We aimed to find AR, ERα, and ERβ in the gubernaculum and inguinal fat pad (IFP) in normal rats and after flutamide treatment. METHODS Sprague-Dawley timed-mated rats were injected with flutamide (75 mg/kg body weight/5% ethanol + oil) on E16-19 or vehicle alone. Male fetuses or pups (5-10/group) were collected at E16; E19; and postnatal (P) days 0, 2, 4, 8. Sections were prepared for hematoxylin and eosin or immunohistochemistry for AR, ERα, and ERβ. Receptor labeling was quantitated as distinct nuclear labeling/100 μm(2) in gubernaculum and IFP. RESULTS There was minimal gubernacular AR-labeling until E19, dramatically increasing postnatally. By contrast, at E16-E19 there was significant IFP AR immunoreactivity suppressed by flutamide (P < .05). No ERα expression was observed, but ERβ was expressed in both gubernaculum and IFP, maximally at E16, but unchanged by flutamide. CONCLUSIONS During the androgen sensitivity window (E16-19), the gubernaculum contains ERβ but minimal ERα or AR, while the IFP, which is supplied by the genitofemoral nerve, contains abundant AR that are flutamide-sensitive. These results suggest that the IFP could be the site of androgenic action controlling gubernacular development.
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Chen N, Harisis GN, Farmer P, Buraundi S, Sourial M, Southwell BR, Balic A, Hutson JM. Gone with the Wnt: the canonical Wnt signaling axis is present and androgen dependent in the rodent gubernaculum. J Pediatr Surg 2011; 46:2363-9. [PMID: 22152883 DOI: 10.1016/j.jpedsurg.2011.09.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 09/03/2011] [Indexed: 01/15/2023]
Abstract
BACKGROUND/AIMS How androgens control inguinoscrotal descent remains controversial but may include canonical Wnt signaling via the transcriptional co-activator β-catenin. The canonical Wnt pathway transcribes genes regulating mesenchymal cell migration, fate, extracellular matrix remodeling, and in addition Axin2, a feedback product that reliably identifies Wnt activation. The relationship between β-catenin and androgen receptor warranted investigation into the involvement of the canonical Wnt pathway in testicular descent. METHODS Gubernacula from male Sprague-Dawley control (n = 22) and flutamide-treated (n = 18) rats at E17, E19, and D0 time-points were processed for immunohistochemistry. Sagittal sections stained for presence of androgen receptor, Axin2, and β-catenin were analyzed by fluorescent confocal microscopy. RESULTS At E19, β-catenin was strongly expressed in the membrane of developing cremaster muscle cells and the cytoplasm of gubernacular core cells. Axin2 expression was ubiquitous in nuclei of gubernacular mesenchymal cells, representing canonical Wnt signaling. After androgen blockade, Axin2 was conspicuously absent in the fibroblasts of the gubernacular core while remaining unaffected elsewhere. Reduced staining of Axin2 in E17 and D0 gubernacula suggests that Wnt signaling coincides with androgen programming. CONCLUSION Axin2 expression in the E19 gubernaculum confirms canonical Wnt pathway activation. Its absence in the core of flutamide-treated gubernacula indicates Wnt down-regulation. As androgen is required for inguinoscrotal descent, downstream Wnt signaling may control initial gubernacular remodeling. Defects in this complex molecular process may play a role in cryptorchidism.
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Affiliation(s)
- Nan Chen
- Murdoch Children's Research Institute, Melbourne, Australia
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Vigueras RM, Reyes G, Moreno-Mendoza N, Merchant-Larios H. Gubernacular fibroblasts express the androgen receptor during testis descent in cryptorchid rats treated with human chorionic gonadotrophin. ACTA ACUST UNITED AC 2004; 32:386-90. [PMID: 15503001 DOI: 10.1007/s00240-004-0408-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Accepted: 02/11/2004] [Indexed: 10/26/2022]
Abstract
Cryptorchidism was provoked in 3 day old rats treated with 17-beta-estradiol over 30 days to identify the cells that express the androgen receptor (AR) during experimental testis descent in the gubernaculum. In one group of animals, testis descent was induced with human chorionic gonadotrophin (hCG) applied daily for 5 or 10 days. A correlative study using a testosterone radioimmunoassay with electron microscopy and immunocytochemical detection of AR was performed in gubernacula of hCG treated and untreated control animals. The gubernaculum of rats undergoing testes descent showed a dramatic increase in the number of AR-positive cells. These were located in the connective tissue among smooth muscle cells in the gubernacular cord and between striated muscle fibers in the bulb. In both regions, the AR-positive cells were identified as fibroblasts. Several clusters of amorphous material appeared in the extracellular matrix of the connective tissue in hCG treated rats. Our results suggest that testosterone induces the expression of AR in gubernacular fibroblasts which seem to degrade the extracellular matrix during gubernacular involution.
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Klonisch T, Fowler PA, Hombach-Klonisch S. Molecular and genetic regulation of testis descent and external genitalia development. Dev Biol 2004; 270:1-18. [PMID: 15136137 DOI: 10.1016/j.ydbio.2004.02.018] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2003] [Revised: 01/18/2004] [Accepted: 02/17/2004] [Indexed: 12/27/2022]
Abstract
Testicular descent as a prerequisite for the production of mature spermatozoa and normal external genitalia morphogenesis, and therefore facilitating copulation and internal fertilization, are essential developmental steps in reproduction of vertebrate species. Cryptorchidism, the failure of testis descent, and feminization of external genitalia in the male, usually in the form of hypospadias, in which the opening of the urethra occurs along the ventral aspect of the penis, are the most frequent pediatric complications. Thus, elucidating the molecular mechanisms involved in the regulation of testis descent and the formation of external genitalia merits a special focus. Natural and transgenic rodent models have demonstrated both morphogenic processes to be under the control of a plethora of genetic factors with complex time-, space-, and dose-restricted expression pattern. The review elucidates the molecular mechanisms involved in the regulation of testis descent and the formation of external genitalia and, wherever possible, assesses the differences between these rodent animal models and other mammalian species, including human.
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Affiliation(s)
- Thomas Klonisch
- Department of Anatomy and Cell Biology, Medical Faculty, Martin Luther University of Halle-Wittenberg, Halle/Saale, Germany.
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Vigueras RM, Moreno-Mendoza N, Reyes G, Merchant-Larios H. Androgen receptor and calcitonin gene-related peptide in neurons of the genitofemoral nerve during testicular descent induced with human chorionic gonadotropin. Arch Med Res 2004; 34:166-70. [PMID: 14567394 DOI: 10.1016/s0188-4409(03)00040-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
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.
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Affiliation(s)
- Rosa María Vigueras
- Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Abstract
INSL3, also designated Leydig insulin-like (Ley I-L) or relaxin-like factor (RLF), belongs to the insulin-like hormone superfamily. It is expressed in pre- and postnatal Leydig cells of the testis and in postnatal theca cells of the ovary. This sexual dimorphic pattern of INSL3 expression during development led us to suggest that the INSL3 factor could play an essential role in sexual differentiation, gonadal function and germ cell development. Key insights into the role of INSL3 came from analyses of INSL3 knockout mice. These mice showed impaired development of the gubernaculum ligament, a structure that is believed to mediate transabdominal descent of the testis during male embryogenesis. In double mutant XY-mice lacking INSL3 and a functional androgen receptor, it was demonstrated that both are essential for establishment of the sexual dimorphic position of the gonads through regulation of gubernaculum development and regression of the cranial suspensory ligament (CSL) during fetal life. Defects in this developmental process can cause cryptorchidism in the male, which is a most common disorder of sexual differentiation in human.
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Affiliation(s)
- I M Adham
- Institute of Human Genetics, University of Göttingen, Heinrich-Düker-Weg 12, 37073, Göttingen, Germany.
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Kassim NM, McDonald SW, Reid O, Bennett NK, Gilmore DP, Payne AP. The effects of pre- and postnatal exposure to the nonsteroidal antiandrogen flutamide on testis descent and morphology in the Albino Swiss rat. J Anat 1997; 190 ( Pt 4):577-88. [PMID: 9183680 PMCID: PMC1467642 DOI: 10.1046/j.1469-7580.1997.19040577.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Exposure of male Albino Swiss rats to the nonsteroidal antiandrogen flutamide during the period from gestational day (d) 10 to birth resulted in feminisation of the external genitalia and the suppression of growth of the male reproductive tract. In adulthood, testes were found to be located in diverse positions. True cryptorchidism occurred in 10% of cases, whereas 50% of testes descended to the scrotum and 40% were located in a suprainguinal ectopic region. Varying degrees of tubule abnormality were seen in the testes of flutamide-treated animals, ranging from completely normal tubules with full spermatogenesis (and the expected frequency of the stages of spermatogenesis) to severely abnormal tubules lined with Sertoli cells only. For each individual testis, the overall severity of tubule damage was strongly correlated with its adult location, with intra-abdominal testes worst affected and scrotally-located testes least; only the latter contained normal tubules. Similarly, intra-abdominal testes were the smallest in weight and contained the least testosterone. By contrast, postnatal treatment of male rats with flutamide from birth to postnatal d 14 did not impair development of the external genitalia, the process of testicular descent or adult spermatogenesis. These findings confirm that androgen blockade during embryonic development interferes with testicular descent but also demonstrate that (1) prenatal flutamide treatment per se has a detrimental effect on adult testis morphology but (2) the degree of abnormality of the testes is strongly influenced by location.
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Affiliation(s)
- N M Kassim
- Division of Neuroscience and Biomedical Systems, University of Glasgow, UK
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Abstract
At present, we believe that descent of the testes within the human is a complex event mediated by both hormonal and mechanical factors. We hypothesize that descent of the testes occurs as a result of the secretion of an androgen-independent factor from a normal testis (descendin). This paracrine factor is responsible for the rapid proliferation (outgrowth) of the ipsilateral gubernaculum. The development of the gubernaculum results in creating a dilated inguinal canal, the width of which matches the testicular width. Descent of the testes through the inguinal canal is an interplay between abdominal pressure, a patent processus vaginalis, and androgen-induced gubernacular regression. We hypothesize that androgens (under control of an intact hypothalamic pituitary axis) alter the viscoelastic properties of the gubernaculum, reducing the turgidity of the gubernaculum and allowing intra-abdominal pressure to push the testis into the scrotum. Cryptorchidism can therefore result when any one or more of the involved factors malfunction.
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Affiliation(s)
- D A Husmann
- Department of Urology, Mayo Clinic, Rochester, Minnesota 55905, USA
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McMahon DR, Kramer SA, Husmann DA. Antiandrogen Induced Cryptorchidism in the Pig is Associated with Failed Gubernacular Regression and Epididymal Malformations. J Urol 1995. [DOI: 10.1016/s0022-5347(01)67109-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Barthold JS, Mahler HR, Newton BW. Lack of feminization of the cremaster nucleus in cryptorchid androgen insensitive rats. J Urol 1994; 152:2280-6. [PMID: 7966725 DOI: 10.1016/s0022-5347(17)31658-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Androgens may control rat testicular descent via effects on the genitofemoral nerve or cranial gonadal ligaments. Androgen-mediated release of calcitonin gene-related peptide from the genito-femoral nerve (whose motoneuron cell bodies reside in the sexually dimorphic cremaster nucleus) may stimulate cremaster sac formation and testicular descent. Alternatively, androgens may cause regression of cranial gonadal ligaments and thereby allow the testes to descend. To evaluate these theories testicular position, and the cremaster sac and nucleus were studied in Tfm (androgen insensitive) rats. Testes were abdominal, inguinal and scrotal in 20%, 67% and 13% of Tfm male rats, respectively, and cranial ligaments were present in all cases. Mean cremaster nucleus motoneuron number was lower in female rats (70 +/- 14) but not significantly different between normal male (256 +/- 44) and Tfm male (231 +/- 42) rats, and it correlated poorly with testicular position. Calcitonin gene-related peptide immunoreactivity was rarely observed in cremaster motoneurons. These data suggest that the cremaster nucleus is not androgen-dependent, calcitonin gene-related peptide release from cremaster motoneurons is not the likely mechanism of testicular descent and persistent cranial ligaments may cause cryptorchidism in the Tfm rat.
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Affiliation(s)
- J S Barthold
- Department of Urology, University of Arkansas for Medical Sciences, Little Rock
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Abstract
The presence or absence of the cremasteric reflex was documented in 225 normal male subjects ranging in age from birth to 12 years. The reflex was initiated by stroking the skin of the inner aspect of the thigh. The cremasteric reflex was present in 48 of 100 newborns (48%), 32 of 71 subjects (45%) between 1 and 30 months old, and all 54 boys older than 30 months. The presence of the cremasteric reflex may be clinically significant in boys with suspected cryptorchidism or acute scrotal inflammation.
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Affiliation(s)
- R E Caesar
- Division of Urology, University of California, San Diego
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