HCG treatment increases intratesticular pressure in the abdominal testis of unilaterally cryptorchid rats

Adult, unilaterally cryptorchid rats were given a single subcutaneous injection of hCG. HCG treatment of 100 I.U. (but not 10 I.U.) resulted in a marked increase in intratesticular pressure (approximately 40 mm Hg) in the abdominal testis that was maximal 24 hours after treatment. This increase in pressure is caused by increased vascular permeability coupled with insufficient lymph drainage. In the scrotal testis, hCG treatment resulted in increased vascular permeability and lymph flow, but this did not result in a marked increase in testicular pressure. No morphologic signs of hCG-induced damage were observed in either the abdominal or scrotal testis 10 days after hCG treatment. Testicular microcirculation, as studied by laser doppler flowmetry, was abnormal in the abdominal testis, but hCG treatment inhibited vasomotion in both the abdominal and scrotal testis.     

Early signs of Sertoli and Leydig cell dysfunction in the abdominal testes of immature unilaterally cryptorchid rats

Testicular descent was prevented unilaterally by cutting the gubernaculum testis of newborn rats. When 20 days old unilaterally cryptorchid rats were injected intraperitoneally with 2 μg bFSH per gram body weight and killed 6 h later when testicular testosterone (T) and oestradiol (E₂) concentrations were determined. The increase in E₂ was subnormal in abdominal testes. In 18-day-old unilaterally cryptorchid rats the efferent ducts were ligated bilaterally, and the rats were killed 48 h later. The weight increase, due to accumulation of seminiferous tubule fluid, was significantly greater in the abdominal testes. In contrast, the ABP content of the abdominal epididymis was subnormal in 20-day-old unilaterally cryptorchid rats. Unilateral orchidectomy was performed in 16-day-old unilaterally cryptorchid rats and at 20 days of age intratesticular T and E₂, and plasma FSH and LH concentrations were determined and compared to that in 20-day-old control unilaterally cryptorchid rats. Removal of an abdominal testis resulted in increased plasma FSH and intratesticular E₂, whereas plasma levels of LH and intratesticular levels of T were unaffected. Removal of a scrotal testis resulted in increased plasma FSH and LH coupled with increased intratesticular T and E₂. Rats with a single abdominal testis had higher plasma FSH and LH and intratesticular T, but similar intratesticular E₂, than rats with a single scrotal testis. It is concluded that Sertoli and Leydig cell function are influenced by cryptorchidism at a stage when the temperature difference, and the morphological differences between the testes are very discrete.     

Effect of unilateral cryptorchidism on the intertubular tissue of the adult rat testis: evidence for intracellular changes within the Leydig cells

Adult male rats were made unilaterally cryptorchid for 1, 2 or 4 weeks, and the morphological response of the Leydig cells was then studied using morphometric assessment of total Leydig cell volume and number per testis in abdominal and scrotal testes. Serum hormone levels were measured and the steroidogenic properties of isolated Leydig cells were evaluated by in-vitro stimulation with hCG and interstitial fluid (IF) obtained from normal rat testes. Total Leydig cell volume and number per testis were not altered in abdominal vs scrotal testes, although the volume of the abdominal testis was 46, 29 and 21%, respectively, of the volume of the contralateral scrotal testis after 1, 2 and 4 weeks. This reduction was accompanied by significant (P less than 0.05) elevation of the serum levels of FSH and LH, although serum testosterone levels were unchanged from the normal range. Despite the lack of quantitative alterations in Leydig cell morphology, hCG- and IF-stimulated testosterone production was significantly (P less than 0.01) greater by abdominal Leydig cells when compared with scrotal Leydig cells derived from the same animals. Ultrastructural examination of Leydig cells in situ suggested an increase in volumetric density of mitochondria in abdominal Leydig cells. Together with the enhanced steroidogenic responses of these cells, these findings suggest that disruption of spermatogenesis in the cryptorchid testis is accompanied by intracellular activation of Leydig cells. Since these effects were not exhibited by Leydig cells from the scrotal testis it is concluded that local factors within the cryptorchid testis are responsible, at least in part, for regulation of Leydig cell activity.     

Interaction of hCG with testicular interstitial fluid produces a leucotactic factor

An intratesticular injection of hCG (5 ng) mixed with testicular interstitial fluid (IF) increases vascular permeability in the rat testis. The present results show that the permeability increase induced by this treatment is accompanied by a massive accumulation of polymorphonuclear leucocytes (PMNs) in both the testicular postcapillary venules and the interstitium. Depletion of neutrophils in the circulation by treatment with anti-neutrophil serum significantly inhibited the permeability increase induced by this treatment. An intratesticular injection of PMNs (10(7) cells) or hCG alone had no effect on permeability, but a combination of the two caused a significant increase in permeability. The PMNs were found to secrete a component in vitro which, when injected intratesticularly together with hCG, caused a increase and a simultaneous massive accumulation of PMNs in the postcapillary venules and interstitium. This permeability increase was prevented by the serine protease inhibitor p-aminobenzamidine, suggesting an involvement of the plasminogen activator system in the response. The results suggest that hCG interacts with an IF component to produce leucotactic factors that increase permeability indirectly by attracting PMNs to the tissue, and that the IF component may originate in the PMNs.     

Investigations of arterio-venous anastomoses in the spermatic cords and blood supply, oxygen consumption and testosterone production of scrotal and abdominal testes in the pig

This study has investigated blood flow from the testicular artery to the pampiniform plexus in the spermatic cord of pigs. Testosterone levels, oxygen tension and the degree of acidity were measured in arterial and venous blood vessels of scrotally and abdominally located testes. Haemoglobin oxygen saturation was derived from the oxygen dissociation curve. Blood flow to abdominal and scrotal testes and epididymides was measured using the radioactive microsphere technique. Average blood flow to the scrotal testes and epididymides was 21 and 8 ml/min, respectively, in normal pigs. In unilaterally cryptorchid pigs average blood flow to the scrotal testis and epididymis was 23 and 6 ml/min, respectively, and to the abdominal testis and epididymis 4.2 and 1 ml/min. In pigs with bilateral scrotal testes oxygen consumption was 16 mumol O2/min/100 g. In unilaterally cryptorchid pigs oxygen consumption by the scrotal testis was 18 mumol O2/min/100 g, compared with 10 mumol O2/min/100 g by cryptorchid testes. From the percentage oxygen saturation in the various blood vessels it was calculated that 29-42% of testicular arterial blood was flowing through arteriovenous anastomoses between the testicular artery and the pampiniform plexus in the spermatic cord, thus bypassing the capillary net of the abdominal testes of unilaterally and bilaterally cryptorchid pigs. These results were supported by the testosterone measurements. In the spermatic cord of scrotal testes no blood bypassed the capillary net of the testes.     

Effect of cryptorchidism on testicular and Leydig cell androgen production in the mouse

Unilateral cryptorchidism was induced surgically in adult mice and the effects on testicular and Leydig cell steroidogenesis were studied after 7 weeks. There was a 60% reduction in weight of the cryptorchid testis and this was associated with a significant reduction in intratesticular androgen content, both under basal conditions and following an injection of hCG. Testicular androgen production in vitro was also significantly lower in the cryptorchid testis compared to the scrotal testis, again under both basal conditions (29 +/- 6% of control) and in the presence of hCG (46 +/- 9% of control). Scrotal testes from the unilaterally cryptorchid animals did not show any significant difference in steroidogenic capacity compared to testes from untreated control animals. The decrease in steroidogenic capacity of the cryptorchid testis was due, at least in part, to a reduction in activity for each Leydig cell. In four experiments, androgen production by Leydig cells isolated from cryptorchid testes was 48 +/- 9% of cells from scrotal testes in the presence of a saturating dose of hCG. Under basal conditions the effect was more variable between experiments with steroid secretion by Leydig cells from cryptorchid testes being 58 +/- 32% of that for cells from scrotal testes. Leydig cell steroidogenesis in the scrotal testes of unilaterally cryptorchid animals did not differ significantly from untreated controls. These results show that induced cryptorchidism in the mouse causes a significant reduction in Leydig cell activity. This is apparently different from the effects of this procedure on the rat and raises the possibility that intratesticular regulation differs between the two species.     

Testicular DNA synthesis in vivo: comparison between unilaterally cryptorchid testis and contralateral intact testis in mouse

DNA synthetic activity was studied by autoradiography in unilaterally cryptorchid (abdominal) and contralateral intact(scrotal) testes in mice. Nongerm cells were inactive in DNA synthesis in both the cryptorchid testis and in the intact control. Labeling indices of undifferentiated type A spermatogonia did not show any differences, indicating that type A spermatogonia did not temperature sensitive in DNA synthesis in vivo.     

Intratesticular factors and testosterone secretion. Effect of treatments that alter the level of testosterone within the testis

The authors recently have reported the presence of a nongonadotropic polypeptide factor in rat testicular interstitial fluid that can exert marked stimulatory effects on Leydig cell testosterone production. To assess the potential physiologic significance of this factor, its effective levels in rat interstitial fluid have been investigated in response to treatments that either markedly reduce interstitial fluid testosterone concentrations (anti-LH treatment; transient or chronic experimental cryptorchidism; destruction of Leydig cells with ethane dimethanesulphonate) or that significantly elevate testosterone levels in interstitial fluid by injection of hCG. The possible relationship between this factor and changes in testicular weight, serum LH and FSH, and interstitial fluid volume also were monitored. When testosterone levels in interstitial fluid were decreased by 75 to 99% either acutely (5-72 hours) or chronically (20-75 days), there was an accompanying increase (P less than 0.001) in the levels of the interstitial fluid factor(s), as determined by the ability of charcoal-stripped interstitial fluid from individual rats to enhance hCG-stimulated testosterone production by Percoll-purified Leydig cells in vitro. Anti-LH treatment increased the levels of the interstitial fluid factor(s) over the ensuing 5 to 48 hours. In abdominal testes from rats made unilaterally or bilaterally cryptorchid for 20 or 55 days, a decrease in interstitial fluid testosterone levels was associated with increased levels of the interstitial fluid factor(s). The same inverse relationship was found 72 hours after treatment with ethane dimethanesulphonate in which Leydig cells had disappeared from the testis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Impaired estrogen production by Leydig cells of the naturally retained testis in unilaterally cryptorchid boars and stallions

Estrogen production in vitro was compared for Leydig cells from cryptorchid and scrotal testes in boars and stallions. Animals with natural and experimental cryptorchidism were used. Purified Leydig cells were prepared from testes of mature animals by collagenase treatment and Percoll density gradients. After incubation for 3 hours (1 X 10(6) cells), estrone sulfate and estrone in the media were measured by direct radioimmunoassay. Androstenedione and testosterone in media extracts also were determined. Cells from the abdominal testis of unilateral cryptorchid boars and stallions showed impaired estrogen production compared with that of the contralateral scrotal testis. Surgical translocation of the scrotal testis to the abdominal cavity in four unilaterally cryptorchid, prepubertal boars did not result in a reduced capacity for estrogen secretion by Leydig cells examined after puberty. Cells from the naturally retained testis in each of these four animals produced practically no estrogen. In a naturally bilateral cryptorchid stallion, there was a high rate of estrogen secretion by both testes. It was concluded that the scrotal testis of a unilaterally cryptorchid animal exerts a suppressive influence on estrogen formation by the abdominal testis.     

Experimental cryptorchidism inhibited growth of the rat ventral prostate

Adult Sprague-Dawley male rats, weighing about 350 g, were rendered cryptorchid by suturing the testes to the lateral abdominal wall. Twenty-eight days later, cryptorchidism resulted in a significant decline in testis weight and suppressed spermatogenesis. The ventral prostate was significantly smaller in cryptorchid rats. There was no significant difference in serum testosterone levels between the normal and cryptorchid rats. Charcoal-stripped aqueous extracts of the testis from intact and cryptorchid animals were tested on primary cultures of rat prostatic stromal cells. Cultures treated with extract from the intact testis had a significantly increased cell proliferation as assessed by cell count and by the rate of 3H-thymidine incorporation. Additionally, extracts of seminiferous tubules significantly increased prostate stromal cell proliferation compared to extracts of testicular interstitial components. Furthermore, this proliferative effect of testicular extracts is specific to the prostate as extract of both normal and cryptorchid testis stimulated proliferation of rat footsole fibroblasts in culture, but only extracts from intact testis stimulated proliferation of prostate stromal cells. These observations demonstrate that the testis produces nonandrogenic substances that can promote growth of prostatic stromal cells and that these substances were eliminated in the cryptorchid testis.     

Production of lactate and tissue plasminogen activator in vitro by seminiferous tubules obtained from adult unilaterally cryptorchid rats

Pieces of seminiferous tubules obtained from adult unilaterally cryptorchid rats were incubated in vitro and the effect of FSH on the secretion of lactate and tissue-plasminogen activator (t-PA) was studied. Tubules from abdominal testes secreted less lactate than scrotal tubules. On the other hand, the basal secretion of t-PA was similar but the FSH-stimulated t-PA secretion was larger from abdominal than from scrotal tubules. These results indicate a more specific dysfunction of the Sertoli cells in cryptorchidism than earlier recognized.     

Testicular Development in the Unilaterally Cryptorchid Rat

By cutting the distal part of gubernaculum testis in newborn rats cryptorchism was produced. This new method to obtain cryptorchid animals has the advange of preventing testicular descent before it normally takes place, thus mimicking congenital cryptorchism. Unilaterally cryptorchid rats were examined at 20, 30 and 100 days of age. Morphometric methods were used to compare the structure of the abdominal and the scrotal testicles during development. In the abdominal testicles some tubular cells were damaged already at 20 days of age, i. e. when the temperature difference between the testicles probably is quite small.
In the abdominal testicles the pathological changes of the tubules precede those of the interstitium. The descended testicles of unilaterally cryptorchid rats were identical to testicles of normal control rats, and all the operated rats were fertile at adult age.     

The changes in testicular vascular permeability during progression of the experimental varicocele

OBJECTIVES: The vascular permeability of testicular capillaries which play a role in controlling the formation of testicular interstitial fluid was studied during the progressive course of experimental varicocele. MATERIALS AND METHODS: The pathology was developed through partial ligation of left renal vein in four groups of rats. Controls of each group were subjected to sham surgery. After different periods of varicocele creation (1, 3, 6 and 14 weeks), animals' testes per one of the study groups were extirpated and weighed. The volume density percentages of polymorphnuclear leukocytes (PMN) per testicular blood vessels; which are markers of the increase in vascular permeability, were also estimated in both testes. To further verify the obtained findings, another group of animals received human chorionic gonadotrophin (hCG) treatment 6 weeks after varicocele creation and their histopathological sections were examined. RESULTS: Animal testes' of (1 and 3 weeks) groups were found to be significantly heavier (p<0.05) than their controls. PMN showed accumulation in testicular blood vessels and their volume density percentages per these blood vessels in both testes were significantly higher in each study group than in those of its controls. However, these percentages showed gradual significant decline as the duration of varicocele bearing gradually increased. The hCG-treated animals revealed more accumulation of the PMN in their histopathological sections. CONCLUSION: The present results suggest that experimental varicocele may induce an increase in testicular vascular permeability, which then decreases gradually with time. It is supposed that parallel changes in the rate of formation of testicular interstitial fluid may be accompanied. The results have also showed that the vasculature of the testis with experimental varicocele can still respond to hCG.     

Treatment with an LHRH agonist or hCG increases interstitial fluid volume and permeability to Evans blue in the mouse testis

Treatment of adult mice with 1 microgram of an LHRH-agonist or with 5 i.u. hCG, subcutaneously, resulted in an increase in the permeability to intravenously injected Evans blue into the testicular interstitial space and in the volume of testicular interstitial fluid. These changes are probably related to an increase in vascular permeability but, in contrast to the situation in rats, this was accompanied neither by an accumulation of polymorphonuclear leucocytes in testicular blood vessels nor by the formation of large inter-endothelial cell gaps in postcapillary venules. The mechanisms mediating the gonadotrophin-induced increase in vascular permeability in the mouse testis thus remain unknown.     

Local regulation of Leydig cells by the seminiferous tubules. Effect of short-term cryptorchidism

Unilateral cryptorchism was induced in adult rats for 24 h, and its effect on testicular morphology and intratesticular testosterone concentration after hCG-stimulation were studied. In seminiferous, tubules from abdominal testes an increased number of degenerating germ cells was noted in stages XIV-III of the spermatogenic cycle and Sertoli cells contained an increased amount of lipid droplets in stages XIV-VIII. However, germ cells and Sertoli cells from tubules at other stages of the cycle appeared unaffected. In scrotal testes the size of peritubular Leydig cells varied in phase with the spermatogenic cycle. The largest cells were found adjacent to stage VII-VIII and the smallest adjacent to stage XI-XII. In abdominal testes no stage-dependent variation in the size of peritubular Leydig cells was seen. Perivascular Leydig cells were of equal size in abdominal and scrotal testes. The testicular testosterone concentration following stimulation with a low dose of hCG was significantly lower in abdominal testes. It is suggested that the seminiferous tubules locally modulate Leydig cell function and that the stage specific stimulatory influence from stage VII-VIII is rapidly lost during experimental cryptorchidism.     

Recovery of testicular functions after surgical treatment of experimental cryptorchidism in the rat

When rats were made unilaterally cryptorchid at 17 days of age (before spontaneous descensus), the further maturation of the testis was prevented. At 34 days of age, the abdominal testis was smaller than the scrotal testis and showed less secretion of the Sertoli cell specific androgen binding protein (ABP). In 120–130 days old rats that were made bilaterally cryptorchid at 17 days of age, testicular weight, histology, secretion of fluid and ABP were restored and testosterone secretion and fertility were normal if orchidopexy was performed at 33 days of age. If the orchidopexy was delayed until 59 days of age, the recovery of testicular function and morphology was only partial. The results show that in the rat, the testicular damage caused by cryptorchidism is reversible, if the abdominal testis is surgically descended during early sexual maturation.     

Recovery of testicular functions after surgical treatment of experimental cryptorchidism in the rat

When rats were made unilaterally cryptorchid at 17 days of age (before spontaneous descensus), the further maturation of the testis was prevented. At 34 days of age, the abdominal testis was smaller than the scrotal testis and showed less secretion of the Sertoli cell specific androgen binding protein (ABP). In 120-130 days old rats that were made bilaterally cryptorchid at 17 days of age, testicular weight, histology, secretion of fluid and ABP were restored and testosterone secretion and fertility were normal if orchidopexy was performed at 33 days of age. If the orchidopexy was delayed until 59 days of age, the recovery of testicular function and morphology was only partial. The results show that in the rat, the testicular damage caused by cryptorchidism is reversible, if the abdominal testis is surgically descended during early sexual maturation.     

Effect of cryptorchidism on the morphology of testicular macrophages: Evidence for a Leydig cell-macrophage interaction in the rat testis

Macrophages and Leydig cells in the testes of adult rats which had been made bilaterally or unilaterally cryptorchid at birth were examined by morphometry for total mass, total number, volume density, and individual cell profile area. The total Leydig cell mass and the average size of Leydig cells, as well as the total mass and the average size of macrophages, were reduced in unilateral abdominal testes, but were unchanged in bilateral abdominal testes when compared to scrotal testes. Leydig cell and macrophage morphology were correlated suggesting a functional coupling between these cell types. The physiological significance of this cell interaction remains to be discovered.     

Effects of repeated injections of human chorionic gonadotrophin on vascular permeability, extracellular fluid volume and the flow of lymph in the testes of rats

Testicular lymph flow, interstitial fluid volume and vascular permeability have been measured in adult male rats injected subcutaneously with hCG daily for up to 4 consecutive days. Albumin clearance was also measured in rats given two or three hCG injections at 2- or 3-day intervals, or every 2 days for 22 days. While a single dose of hCG increased vascular permeability and lymph flow within 24 h, subsequent daily injections did not produce any additional response and, in fact, values returned towards control levels. A second hCG dose 2 days after an initial dose did produce another similar increase in the clearance of albumin injected directly into the testis and, with continued injections every second day, a response was still evident after 22 days. The response to the second dose of hCG occurred at a time when down-regulation of hCG receptors on Leydig cells is reported to be maximal. These results suggest that in the testis, the vascular response to hCG does not require the normal number of luteinizing hormone (LH) receptors, although other evidence suggests that Leydig cells must somehow be involved.     

Laminin, type IV collagen, and fibronectin in normal and cryptorchid human testes. An immunohistochemical study

An immunohistochemical study of laminin, type IV collagen, and fibronectin was carried out in the testes of normal men and in the cryptorchid and contralateral scrotal testes of cryptorchid men from 2 to 40 years of age. The integrated optical density (IOD) per unit area of the lamina propria was measured in the immunostained sections. Fibronectin was found throughout the thickness of the lamina propria of the seminiferous tubules and in the interstitial connective tissue. No differences between normal and cryptorchid testes were found. Laminin was observed in the innermost part of the lamina propria of the seminiferous tubules and surrounding the endothelium of blood capillaries from infancy. No differences were found between normal and cryptorchid testes in the prepubertal period. In adult cryptorchid testes, laminin formed more numerous and deeper invaginations towards the seminiferous epithelium than in normal adult testes. Type IV collagen appeared throughout the thickness of the lamina propria of normal testes as well as in the wall of interstitial blood vessels. From infancy, the lamina propria of seminiferous tubules, but not blood vessel walls, showed lesser immunostaining for type IV collagen and a lower IOD of this component than did control tests from men of the same age. No differences between unilateral and bilateral cryptorchidism were found. The contralateral scrotal testes of cryptorchid males showed intermediate immunostaining for type IV collagen between that of normal control testes and that of cryptorchid testes. These findings suggest that the lamina propria of seminiferous tubules is lesioned at an early age in both cryptorchid and contralateral scrotal testes of cryptorchid men.