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A. D. JOHNSON, W. R. GOMES, M. J. FREE and N. L. VanDEMARK

Summary.

Testes of thirty mature male rabbits were used to determine the effects of surgery and artificial cryptorchidism on weight and lipid changes in the testes 6 days after treatment. Twelve testes were analysed from each of five groups including: (1) unoperated controls, (2) sham-operated controls, (3) and (4) a unilaterally cryptorchid group which supplied both contralateral scrotal testes and abdominal testes, and (5) a bilaterally cryptorchid group.

Scrotal testes of sham operated and of unilaterally cryptorchid rabbits did not differ significantly from controls in any respect. Unilateral or bilateral cryptorchidism caused a decrease in testis wet and dry weight. Total lipid per testis varied in experimental groups, but total lipid per gram of dry weight was not significantly affected by treatment. Unilaterally cryptorchid testes had higher cholesterol concentrations than the contralateral scrotal testes and the control testes, but the bilaterally cryptorchid testes did not differ significantly from controls. Unilaterally and bilaterally cryptorchid testes increased in esterified cholesterol and lipid phosphorus concentrations. In general, bilateral operations resulted in a response intermediate between the control and comparable unilateral operations.

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A. K. Susheela and A. Kumar

Summary. Fluoride was orally administered to rabbits at 10 mg NaF/kg body weight for 18 or 29 months. The animals were then killed and the structure of the testis, epididymis and vas deferens studied under light and scanning electron microscopes. In animals treated for 29 months, the spermatogenic cells in the seminiferous tubules were disrupted, degenerated and devoid of spermatozoa. In animals treated for 18 or 29 months, loss of cilia on the epithelial cells lining the lumen of the ductuli efferentes of the caput epididymidis and of stereocilia on the epithelial cells lining the lumen of the vas deferens was observed. In some regions of the epithelial lining of the lumen of the ductuli efferentes and vas deferens, the boundaries of the cells were not clear and appeared to be peeled off. Mucus droplets were abundant in the vas deferens of control animals, but absent in both the treated groups. Spermatogenesis ceased only in animals treated for 29 months. The difference in the structural changes observed in the testes of the 2 treated groups may have been due to the blood–testis barrier. It is concluded that ingestion of high concentrations of fluoride has harmful effects on the male reproductive system.

Keywords: fluoride toxicity; spermatogenesis; ductuli efferentes; rabbit

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P. van der Schoot

Summary. Exposure of rats in utero to the anti-androgen flutamide resulted in feminization of the external genitalia that was noticeable at birth. This exposure also resulted in a high degree of cryptorchidism during adulthood. In most affected animals, testes were lying in 'ovary position' close to the caudal pole of the ipsilateral kidney. Cryptorchidism occurred despite normal prenatal development of the gubernacular cones and the transformation of these structures, postnatally, into muscular cremaster sacs.

Inter- and intralitter variation in the response to prenatal exposure to flutamide was observed as well as intra-individual variation. Cryptorchidism frequently occurred unilaterally with right side cryptorchidism predominating.

Cryptorchidism occurred in association with marked suppression of the growth of the ipsilateral epididymis and deferent duct. The possibility is considered that the poor development or absence of these structures contributes to cryptorchidism. Intra-individual variation supports the concept of the local nature of the influence of testis hormones in stabilization and further differentiation of the ipsilateral Wolffian duct derivatives.

Cryptorchidism was enhanced when rats were treated postnatally with testosterone or oestradiol. The effect of testosterone was unexpected in view of the generally held hypothesis that androgens enhance testis descent. The effect of oestradiol was as expected: other animal models have been described in which induction of cryptorchidism by oestradiol occurs. Additional treatment with oestradiol caused further suppression of growth of the epididymis and deferent duct.

The response to prenatal exposure to flutamide was not altered by further injections of flutamide postnatally. Such injections were without effect in males not exposed to flutamide prenatally except for minor, but statistically significant, testicular enlargement during adulthood.

A model is thus presented that describes cryptorchidism as an endogenous developmental disorder.

Keywords: anti-androgen; flutamide; testis descent; cryptorchidism

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R. M. Sharpe

Summary. The specific testicular uptake in vivo of 125I-labelled hCG was compared in control adult rats and adult rats made bilaterally cryptorchid 5 weeks previously. Although a similar temporal pattern of uptake was observed in both groups, uptake of hCG by cryptorchid testes was reduced at all times after injection by up to 70%. The possible causes of this impairment were investigated. It could not be accounted for by differences in the rate of absorption or clearance of 125I-labelled hCG in the two groups. Therefore, because hCG-induced increase in the permeability of testicular capillaries is a crucial factor in determining hCG uptake by the testis, this change was compared in control and cryptorchid testes. Although hCG induced a characteristic increase in testicular capillary wall permeability in both groups, this change was temporally delayed in cryptorchid testes, and occurred after hCG values in the blood had fallen. Even when hCG had crossed the capillary wall into testicular interstitial fluid, its uptake into the testicular tissue was significantly lower in cryptorchid than in control testes. These changes probably account for the impairment of gonadotrophin uptake by the cryptorchid testis and have important implications with respect to the aetiology of Leydig cell changes in cryptorchidism.

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C. Taragnat, M. Berger and Cl. Jean

Summary. Polyacrylamide gel electrophoresis analysis revealed that the vas deferens of adult mouse contains a major protein. Mouse vas deferens protein is a basic glycoprotein with a molecular weight of 34 800 ± 300. The protein represents 17 ± 0·7% and 42 ± 2·4% of soluble proteins from homogenate and luminal fluid respectively, an estimate based on densitometric scanning of polyacrylamide gels. The protein originated from the vas deferens since it was not detected in blood plasma or in sexual organs and it was still present after ligation of the epididymis.

Changes in androgen status of the animal markedly affected the vas deferens protein. After castration a progressive decrease in the protein was observed and its relative percentage dropped to 2 ± 0·4% after 45 days. The concentration of the protein returned to precastration levels after 2 weeks of testosterone treatment but oestradiol, progesterone and corticosterone were ineffective in this respect. The vas deferens protein was not synthesized in significant amounts until animals were 20 days old and its concentration increased rapidly from 20 to 30 days in concert with the pubertal increase of androgens in the vas deferens.

Keywords: vas deferens; major protein; androgens; mouse

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EJ Peirce, HD Moore, CM Leigh and WG Breed

The cauda epididymidis, with its relatively cool temperature (32-35 degrees C), is considered to be the main site of sperm storage in male mammals. However, in the adult male spinifex hopping mouse, Notomys alexis, similar numbers of spermatozoa are found in the vas deferens to those in the cauda epididymidis. The present study shows that, unlike in the laboratory mouse in which spermatozoa of the vas deferens are found mainly in the epididymal region of the duct, spermatozoa in the hopping mouse are localized mainly to the middle and urethral regions of the vas deferens which lies in the inguinal and lower abdominal region of the body cavity. After ligation of the vas deferens close to its connection with the epididymis, many spermatozoa in the vas deferens retain the potential for motility for up to 2 weeks, indicating that the viability of spermatozoa is not compromised by being restricted to core body temperature. This urethral region of the vas deferens, in which spermatozoa reside, has a highly divergent structural organization compared with that of common laboratory rodents in which there is an expanded lumen with a network of epithelial folds. Ultrastructural observations of the cells lining the duct indicate that there are not any marked differences in morphology compared with the cells lining the duct in common laboratory murids, but the infoldings of the vas deferens of the hopping mouse are highly vascular which might facilitate supply of oxygen and nutrients to the spermatozoa residing in the lumen.

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H. Hayashi and A. P. Cedenho

Summary. Rats were surgically made bilaterally cryptorchid and after 4–8 days the testes were returned to the scrotum. After 70 days fertility was tested by pairing with females. Fertility was restored in 5/6 rats with testes cryptorchid for 4 or 5 days, but only 2/9 were fertile when the duration of cryptorchidism was 6–8 days. The sterility was due to irreversible degeneration of the spermatogonial stem cells. The testes of infertile males were smaller and lighter than those of fertile males and the seminiferous tubule diameters were reduced.

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T. W. SCOTT, R. G. WALES, J. C. WALLACE and I. G. WHITE

Summary.

Chemical analyses have been made on fluid from the testis, caput epididymis, cauda epididymis and vas deferens of the ram. The most striking finding was a decrease in the concentration of sodium and chloride in passing from the testis through the epididymis to the vas deferens with a corresponding increase in glycerylphosphorylcholine (gpc) and total phosphorus. The concentration of protein and total orcinol-reactive carbohydrate was also much higher in the epididymis and vas deferens than in the testis. The synthesis of gpc has been demonstrated in the head and tail of the rabbit epididymis both in vivo and in vitro using 32P orthophosphate.

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R. M. LIPTRAP and J. I. RAESIDE

It is well established that cryptorchidism is associated with degeneration of the seminiferous tubules, but there is less certain knowledge concerning the internal secretory capacity of the abdominal testis. Although unilaterally and bilaterally cryptorchid boars are able to excrete dehydroepiandrosterone (DHA) and oestrogens in amounts comparable to those of normal boars (Liptrap & Raeside, 1970), the abdominal testes of such animals show a limited response to gonadotrophin stimulation (Liptrap & Raeside, 1971). The purpose of the present study was to determine if the higher abdominal temperature was responsible, at least in part, for the limited response of the cryptorchid testis to stimulation by hcg, as reflected in the urinary excretion of DHA and oestrogens.

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G. P. Risbridger, J. B. Kerr, R. Peake, K. A. Rich and D. M. de Kretser

Summary. Adult rats were made bilaterally cryptorchid and studied at intervals of 3, 7, 14 or 21 days to study temporal changes in Leydig cell function. Serum FSH and LH levels were measured and the cross-sectional area of the Leydig cells assessed by morphometry. The function of the Leydig cells was judged by the binding of 125I-labelled hCG to testicular tissue in vitro and the testosterone response of the testis to hCG stimulation in vitro. By 3 days after cryptorchidism, the binding of labelled hCG to testicular tissue was significantly decreased compared to that of controls, but the testes were able to respond to hCG stimulation in vitro. At 7, 14 and 21 days after cryptorchidism, an enhanced testosterone response was observed and the size of the Leydig cells was significantly greater than that of the controls, which indicated increased secretory activity by the cryptorchid testis. Although serum FSH levels were significantly elevated after 3 days of cryptorchidism, serum LH levels did not rise until 7 days, thereby suggesting that the loss of receptors is unlikely to result from down-regulation by LH. The reduced testosterone response of the cryptorchid testis in vivo to low doses of hCG and the enhanced response at high doses are probably related to the reduced blood flow to the cryptorchid testis and the decreased sensitivity of the Leydig cells induced by LH/hCG receptor loss.