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L. L. EWING and N. L. VANDEMARK

Summary.

Investigations were conducted on the in-vitro metabolic activity of rabbit testicular tissue after exposing the testis to abdominal temperatures for 2, 6 or 24 hr. Metabolic activity increased with the shorter exposure and then significantly decreased as compared with that of normal testicular tissue. Tissue treated in this way recovered its normal metabolic activity when subjected for 30 min to an ice-cold glucose solution. Tissues exposed to abdominal temperature for 24 hr were found to contain 12% less glucose and 27% less lactic acid than control tissues. This study suggests that spermatogenic arrest which results from exposure of the testis to elevated temperatures may be caused by reduced levels of substrate in the tissue.

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N. L. VANDEMARK and L. L. EWING

Summary.

A simple and inexpensive apparatus for perfusing the mammalian testis has been developed. Glucose utilization, rate of blood flow, and histological examination have indicated maintenance of certain areas of the isolated organ. Successful perfusions have been carried out over a 7-hr period. Preliminary findings suggest that nutrient requirements of the testis may be determined by this technique.

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L. L. EWING and N. L. VANDEMARK

Summary.

In several investigations of the effect of higher than normal scrotal temperatures on metabolic activity of rabbit testis, oxygen uptake, glucose utilization and lactic acid accumulation of testicular tissues were compared with those of kidney cortex slices. Also, glucose utilization and rate of blood flow through the isolated, perfused rabbit testis were measured. When an adequate amount of substrate (0·055 m glucose) was present, the enzyme systems of neither testis nor kidney cortex slices were deleteriously affected by increased temperature (36·5° C versus 39·0° C) in vitro. An increased temperature in vitro caused a decreased glucose uptake by the isolated, perfused rabbit testis. This decrease in glucose uptake corresponded with a decrease in the amount of glucose available to the tissue, as a result of decreased blood flow and increased metabolic activity. These observations further suggest that spermatogenic arrest due to elevating testicular temperature may be caused by a substrate deficiency to the tissue.

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

A number of experiments have shown that the mammalian testis is quite sensitive to changes in atmospheric gases, both in vivo and in vitro. Degenerative changes have been observed in testes of rodents exposed to abnormal levels of oxygen, neon, carbon monoxide and other elements (Cockett & Johnson, 1970).

High levels of carbon dioxide appear deleterious to general systemic responses (Mullenax & Dougherty, 1963) and to sperm cell integrity and male fertility (Mukherjee & Singh, 1967) in vivo; alterations in atmospheric CO2 levels affect metabolism of sperm cells (Salisbury, VanDemark, Lodge & Cragle, 1960) and testicular tissue (Fleeger, VanDemark & Johnson, 1967) in vitro. The changes in testes in vivo following short-term exposure of animals to elevated CO2, however, have not been reported. This study

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

Summary.

Scrotal testes from control and unilaterally cryptorchid rats and rabbits and abdominal testes from animals unilaterally or bilaterally cryptorchid for 6 days were used in this study. Total cholesterol rose (P<0·05) in all abdominal testes as a result of increased (P<0·05) levels of esterified cholesterol. Fatty acids of the scrotal testes from unilaterally cryptorchid animals were only slightly changed by treatment. Changes in fatty acid esters in abdominal testes of unilaterally cryptorchid animals of both species were similar. These changes consisted of increases in most fatty acids with a chain length of 14, 16 and 18, both saturated and unsaturated. Abdominal testes of bilaterally cryptorchid rabbits differed from those of unilateral cryptorchids in that proportions of long chain fatty acids were more consistently increased in the former. Abdominal testes of the bilaterally cryptorchid rats also differed from the unilateral cryptorchids but less than in the rabbit. Differences in hormonal levels in the unilateral and bilateral cryptorchids are suggested as the most probable cause of difference in the abdominal testes of these groups.

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

Summary.

The testis and body temperature of mature male rats and domestic fowl following cadmium (Cd) and/or zinc (Zn) injections, or cryptorchidism, were studied. In the rat, Cd initially caused an increased testicular temperature with the degree of increase dependent upon amount and route of the Cd injection. After the initial increase, which lasted for 50 to 120 min, there was a depression of temperature to below pre-injection levels, again dependent upon Cd level. Body temperature was unchanged with subcutaneous injections of Cd and dropped with intraperitoneal injections. Zinc caused body and testis temperatures to decline and pre-treatment with Zn prevented the increase in testicular temperature following injections of Cd. In the cryptorchid rat and in the fowl, testicular and body temperatures did not differ either before or after treatment. In the cryptorchid and castrated rat, body temperature appeared to decline more than in the rat with scrotal testes after Cd treatment, while in the chicken there was no change in either testis or body temperature.

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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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R. D. BAKER, N. L. VANDEMARK, C. N. GRAVES and H. W. NORTON

Summary.

To determine the effects of parasympathetic-influencing drugs on reproductive phenomena in bulls, four ejaculates were collected at 15-min intervals from each of six bulls beginning 30 min after a subcutaneous injection of 400 mg pilocarpine, 200 mg atropine, or physiological saline solution. Each treatment was administered twice, so that a total of 144 ejaculates was collected. Pilocarpine significantly (P<0·01) decreased the concentration of spermatozoa and increased the time required to mount, the duration of ejaculation, the volume of semen, the number of spermatozoa per ejaculate and the concentration of chloride in the semen. Atropine had the reverse effect on these characteristics and significantly (P<0·01) increased the concentration of fructose in the semen. These results demonstrate that atropine and pilocarpine, which are known to influence the parasympathetic system, alter the reaction time of the bulls, the secretion of one or more accessory sex glands, the passage of spermatozoa through the male reproductive tract, and the emission of semen during ejaculation.

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J. L. FLEEGER, J. P. BISHOP, W. R. GOMES and N. L. VanDEMARK

Summary.

Experiments were conducted using twenty-four mature male rabbits to determine the effects of short-term unilateral cryptorchidism on the fatty acid composition of testicular phospholipids and triglycerides.

Total lipids were extracted from testes from unoperated control rabbits and from rabbits rendered unilaterally cryptorchid for 2, 4 or 6 days. Phospholipids and triglycerides were separated by thin layer chromatography. The methyl esters of the fatty acids in each fraction were separated and measured using gas-liquid chromatography.

The phospholipid fraction was relatively high in the fatty acids palmitate, stearate and oleate whereas the triglyceride fraction contained relatively high levels of oleate, linoleate and palmitate. In the phospholipid fraction of the translocated testes, the proportion of palmitate rose after 2 days (P<0·01), returned to control levels at 4 days, then decreased (P<0·01) 6 days after translocation. Stearate, palmitaldehyde and stearaldehyde concentrations increased (P<0·001) in translocated testes at 4 and 6 days. Concentration of oleate in the phospholipid fraction decreased (P<0·01) after 2 or 4 days and linoleate was lower (P<0·05) than controls after 2 and 6 days of translocation. In the phospholipid fraction of scrotal testes, palmitate percentage increased (P<0·05) at 2 days, and linoleate and stearate decreased (P<0·05) at 2 and 6 days, respectively.

Palmitate concentration in the triglyceride fraction of translocated testes increased (P<0·05) at 2 and 6 days as did stearate percentage (P<0·01) after 6 days. Myristate was also higher after 4 days of translocation (P<0·05). A decreased percentage of oleate was found in the triglyceride fraction of 4- and 6-day translocated testes. Triglycerides from the scrotal testes contained higher levels of palmitoleate (P<0·05) and myristate (P<0·05) than unoperated controls, but lesser percentages of stearate (P<0·01).