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R. M. LIPTRAP and J. I. RAESIDE

Summary.

Urinary levels of DHA and oestrogens were determined in normal, unilaterally and bilaterally cryptorchid boars and in such animals following hemicastration or treatment with hcg. Removal of one testis from normal boars or the abdominal testis from unilaterally cryptorchid boars did not appreciably alter the urinary levels of DHA and oestrogens. Removal of the scrotal testis of unilaterally cryptorchid boars or one abdominal testis of bilaterally cryptorchid boars resulted in a significant drop in urinary steroid values. Except for one boar, DHA returned to within control levels in 2 months while oestrogen values were significantly lower in two animals and significantly higher in one animal at 2 months. hcg treatment caused a highly significant increase in DHA and oestrogen excretion in a normal boar and a unilaterally cryptorchid boar with a scrotal testis remaining after hemicastration. Boars with bilateral cryptorchid testes and a boar with an abdominal testis remaining after hemicastration showed a limited response to hcg injections. The results suggest that the cryptorchid testis of the pig is able to compensate for the loss of the contralateral gonad but the limit of response to gonadotrophin is very much lower and the time of response is slower than that exhibited by the scrotal testis.

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Hannele Yki-Järvinen, T. Wahlström and M. Seppälä

Summary. The biotin—avidin immunoperoxidase staining method and antisera against highly purified porcine relaxin were utilized to localize relaxin in the male genital tract. Formalin-fixed tissue specimens from the prostate gland, the testis, epididymis, vas deferens and the seminal vesicle were studied. Specific relaxin immunoactivity was seen in the glandular epithelium of the prostate and also in the glandular epithelium of the seminal vesicle and in the ampullary part of the vas deferens. The testis and epididymis were negative.

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B. Jégou, A. O. Laws and D. M. de Kretser

Summary. Cryptorchidism for 28 or 10 days resulted in a severe disruption of spermatogenesis (assessed histologically or by fertility tests), Sertoli cell function (assessed by seminiferous tubule fluid production after efferent duct ligation, ABP levels, binding of 125I-labelled FSH to testis homogenates and serum FSH levels) and Leydig cell function (assessed by serum LH and testosterone levels, in-vitro testosterone production, binding of 125I-labelled hCG). Orchidopexy after 28 days of cryptorchidism resulted in a poor recovery of spermatogenesis since the majority of tubules were lined by Sertoli cells and a few spermatogonia. No recovery occurred in the indicators of Sertoli and Leydig cell function.

Orchidopexy after 10 days of cryptorchidism also resulted in a poor recovery of spermatogenesis, with a few animals showing partial recovery after 6 months. No recovery occurred in seminiferous tubule fluid production but partial recovery occurred in ABP content and production rate. Serum FSH, LH levels and in-vitro testosterone production by the testis remained elevated and did not change from the values found during cryptorchidism.

Fertility testing at 6 months revealed a small number of rats in which fertility was restored although the number of embryos was lower than in controls. In this group of animals there was a significant improvement in a number of indicators of Sertoli cell and Leydig cell function. These data provide further evidence to link the changes in Sertoli cell and Leydig cell function to the germ cell complement present in the testis.

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Brian P. Setchell

The evidence for the lower temperature of the testes of many mammals is summarized, and the reasons suggested for the descent of the testes into a scrotum are discussed. Descriptions are given of the various techniques used for studying the effects of heat on the testis, whole body heating, local heating of the testes (by inducing cryptorchidism, scrotal insulation or immersion of the scrotum in a water bath), and heating of tissue or cell preparations in vitro. The effects of heat are discussed, effects on the testis (weight, histology, physiology, biochemistry and endocrinology), on the numbers and motility of spermatozoa in rete testis fluid and semen, on fertilizing ability of spermatozoa and on the subsequent development of the embryos produced when spermatozoa from heated testes are used to fertilize normal ova. The possible mechanisms for the damaging effects of heat are discussed, as well as the importance of heat-induced abnormalities in male reproduction in domestic animals and humans.

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B. D. SCHANBACHER, W. R. GOMES and N. L. VANDEMARK

Summary.

Carnitine acetyltransferase activities have been determined in the testes of developing and cryptorchid rats. This enzyme appears to be associated with the primary spermatocytes and early spermatids of the rat testis since activities increased markedly when these cells were proliferating. The usefulness of carnitine acetyltransferase as a `marker enzyme' in the spermatogenic process is re-emphasized. Serum testosterone levels in the same animals closely paralleled the increased enzymatic activity (r = 0·59; P<0·01). The testes of rats made experimentally cryptorchid contained reduced activity of carnitine acetyltransferase. The enzyme activity of 1-day cryptorchid testes was reduced to approximately half, and the activity of 10-day cryptorchid testes was reduced to one-sixth that of normal adult testes.

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E. D. MASSIE, W. R. GOMES and N. L. VanDEMARK

Investigations by Moore (1924) were among the first to show degeneration of seminiferous elements of the mammalian testes during cryptorchidism. Since that time, a number of experiments have demonstrated that biochemical and metabolic changes occur in the cryptorchid testis, including changes in respiration (Tepperman, Tepperman & Dick, 1949), glucose metabolism (Free, Vera Cruz, Johnson & Gomes, 1968), lipid levels (Fleeger, Bishop, Gomes & VanDemark, 1968) and gas tensions (Cross & Silver, 1962). Alteration in blood gas tensions has been associated with testicular degeneration (Free & VanDemark, 1968; Matteo & Nahas, 1963; Waites & Setchell, 1964) suggesting that a relationship may exist between cryptorchidism, gas tensions in the testis and tubular damage. The present study was undertaken to determine the effects of short-term cryptorchidism on oxygen tension in the rat testis.
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TAPANI VANHA-PERTTULA

Summary.

Four aminopeptidases of rat testicular tissue were quantified during pubertal maturation, after cryptorchidism, and following cadmium chloride treatment. The assay conditions were based on differential substrate and modifier characteristics outlined previously.

Aminopeptidase I with Val-β-naphthylamide (β-NA) and aminopeptidase II with Ala-β-NA and EDTA as activator showed a high activity in the prepubertal testis. A marked increase in activity after cryptorchidism suggested a Leydig cell origin for these enzymes. Aminopeptidase III was characterized as aminopeptidase B and quantified with Arg-β-NA as substrate. The activity of this enzyme closely followed the maturation of spermatogenesis during puberty and showed a rapid decrease after cryptorchidism. The differential quantification of Aminopeptidase IV was unsuccessful but there was evidence to suggest that its origin was in the seminiferous tubules.

There was a suppression of the activity of all four enzymes after cadmium chloride treatment following the necrotic changes in the testis.

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KENT STOCKTON and DONALD C. JOHNSON

Summary.

The follicle-stimulating hormone (fsh) content of the pituitaries of normal, castrated and cryptorchid parabiotic male rats was determined by the augmented ovarian weight bio-assay. These values were compared with those obtained from the same types of animals joined to hypophysectomized—intact, hypophysectomized—castrated, or hypophysectomized—cryptorchid males.

The total amount of fsh in the pituitary was reduced by 38% 1 week after castration of 45-day-old males. Neither increased spermatogenesis plus androgen in scrotal testes, nor increased androgen alone in cryptorchid testes of hypophysectomized parabiotic partners, had any effect upon this reduction. Loss of the germ cells by artificial cryptorchidism did not alter the total amount of pituitary fsh, but the concentration was increased by 19%. Active spermatogenesis in the testes of a hypophysectomized partner had no effect upon pituitary fsh in the cryptorchid male. In no case did a castrated hypophysectomized male influence pituitary fsh in his partner. The results indicate that nothing produced by the testes passed through the blood to alter the fsh content of the pituitary in a parabiotic partner.

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JOSEPH R. DAVIS, ROBERT N. MORRIS and MANNFRED A. HOLLINGER

Summary.

Unilateral cryptorchidism has been produced in prepubertal rats by abdominal fixation of an undescended testis and in adult rats by transplantation of a previously descended testis from the scrotal sac into the abdominal cavity. The incorporation of l-lysine-U-14C into protein of slices of both types of experimentally induced cryptorchid testes 30 days following the surgical procedure has been found to be markedly greater than that observed for slices of contralateral, scrotal testes of the same animal.

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AMAR CHATTERJEE and PARTHOSANKAR RAY

Summary.

Cadmium chloride at a dose level of 0·5 mg/100 g body weight exerted a differential deleterious effect on cryptorchid and contralateral scrotal testes in the same rat. The degenerative changes occurring in the cryptorchid testis 72 hr after cadmium administration were almost comparable to those found after ligation of the spermatic artery for 72 hr and were highly significant compared to those found in the scrotal counterpart.