Variability of venous anatomy of rat testis: application to experimental testicular surgery.

The venous drainage of the testis of the laboratory rat was observed in 31 animals. The right testicular (internal spermatic) vein drained directly into the right common iliac vein in 77.4%, and into the inferior vena cava in 22.6% of the animals. The left testicular vein drained into the left common iliac vein in all animals, but in 90.3% there was also an accessory branch of the testicular vein draining into the left renal vein. These observations suggest that in the rat the exact anatomy of the venous drainage of each testis should be identified prior to undertaking any surgical procedure on the testis where the venous vasculature plays a major role such as testicular transplantation or the creation of an experimental varicocele.

Expression of the androgen receptor gene in rat penile tissue and cells during sexual maturation.

The cessation of rat and human penile growth at completion of sexual maturation appears to be related to a tissue-specific decrease in the number of androgen receptors (AR) in the penis. To find out whether this is due to either transcriptional or translational regulation of the AR gene, we determined the levels of AR mRNA by Northern blots in the corpora cavernosa from groups of 16-, 19-, 22-, 27-, 52-, and 90-day-old rats. The AR mRNA rapidly decreases with age and is nearly undetectable in the 52- and 90-day-old rats, paralleling the decline in AR number. The persistence of a low amount of AR mRNA in the adult penis was confirmed by reverse transcription/polymerase chain reaction amplification of total RNA, and its level was estimated by a semiquantitative modification of this procedure at less than 1/25th of that found in the youngest rats. Smooth muscle cells derived from the 16- and 90-day-old corpora cavernosa express in the AR gene in vitro in approximately the same levels, suggesting that there are factors in culture that up-regulate the AR mRNA. Our results are compatible with the assumption that the age-dependent decrease in AR in the rat penis is due to transcriptional regulation, although they do not exclude the less likely alternative of a selective effect on AR mRNA stability and support the use of this model for studying tissue-specific factors controlling the developmental expression of the AR gene.

Effect of 5-alpha-reductase inhibitor, 4-MAPC, on testicular descent in male rat.

Testicular descent has been reported to be a dihydrotestosterone (DHT) dependent event. To further elucidate the role of DHT in the process of testicular descent, a group of rats were treated with the 5-alpha reductase inhibitor, 4-MAPC, from birth to day 28 of age and the incidence of testicular descent as well as ventral prostate weight was noted at day 29 of age. It was determined that in the doses used, 4-MAPC failed to prevent testicular descent. Because 4-MAPC inhibited ventral prostate weight by only 53% (as compared to a 75% inhibition by castration), the failure of the 4-MAPC to prevent testicular descent could be due to its inability to completely inhibit tissue 5-alpha reductase activity. The results of this study do not mitigate against the role of other nonhormonal factors working in tandem with DHT in the induction of testicular descent in this animal model.

Effect of the antiandrogen, WIN 49,596, on the descent of the testis in the male rat.

Testicular descent in the male rat is believed to be an androgen dependent event with dihydrotestosterone the most likely active androgen. To provide further insight into the endocrinology of this important physiological event, we treated male rats with the antiandrogen, WIN 49596 (50 mg./kg./day), from day 1 to day 27 of age and evaluated its effect on the post-natal androgen-dependent events in this animal model. It was determined that while treatment with WIN inhibited the weights of the ventral prostate, seminal vesicles and penis when compared to those seen in castrate animals, the drug only caused a 19% (3/16) inhibition in the descent of the testes when compared to the control group (0/16; p = 0.112). These data together with those previously obtained in animals exposed to selective inhibitors of the 5-alpha reductase enzyme suggest that other factors possibly working in tandem with androgens play a predominant role in testicular descent in the rat.

Inhibition of fatty acid-supported mitochondrial respiration by cyclosporine.

We have shown that, in addition to inhibition of the succinate-supported energy pathway (5), CS inhibition of mitochondrial Complex II activity also limits fatty acid oxidation. These results are consistent with the participation of altered lipid metabolism in CS nephrotoxicity.

Long-term effects of prepubertal testicular vessel ligation on testicular function in the rat.

To determine the effects of unilateral testicular vein and artery ligation in the immature rat on the function and final location of the testis at adulthood, 10-day-old male rats underwent either a sham operation or unilateral ligation of these vessels of the still undescended testis. Testicular location, blood flow, size and histology as well as ventral prostate weights were measured 50 days later at adulthood. At age 60 days, it was determined that all testes were descended into the scrotum, and there were no differences in testis and ventral prostate weights, intratesticular sperm counts and mean seminiferous tubular area between the control and sham operated animals. However, there was an 18% reduction in testicular blood flow (ml. per 100 gm. per minute +/- standard error of mean) in the operated animals when compared to the sham (20.43 +/- 1.10 versus 16.69 +/- 0.74, p less than 0.02). These data indicate that although there is a slight but significant reduction in testicular blood flow at adulthood when the testicular artery and vein are ligated early in life, this diminution is not sufficient to alter the ultimate location, testicular weight and spermatogenic function of the testis. This would suggest that after ligation of the main testicular vessels to the immature testis, the collateral blood supply is able to compensate with time to allow normal growth and development of the testis. These experimental observations provide additional support for the 2-staged approach to the high undescended testis whereby the testicular vessels are initially ligated and a subsequent procedure is performed to place the undescended testis into the scrotum.

Kinetics of cyclosporine A-induced inhibition of succinate-coenzyme Q dehydrogenase in rat renal cortical mitochondria.

The kinetic mechanism of succinate-coenzyme Q dehydrogenase (Complex II) inhibition by cyclosporine A (CS) on rat renal cortical mitochondria was investigated. CS showed two modes of inhibition of Complex II of the mitochondrial electron transport system: (a) a mixed linear noncompetitive inhibition of resting succinate-limited and ADP-stimulated respirations suggesting that CS binds to Complex II at a different site than the substrate, affecting the dissociation constant for the enzyme-substrate complex and (b) a competitive inhibition of the DNP-stimulated electron transport system suggesting competition with the oxidized form of a component of Complex II. CS action to renal mitochondrial Complex II limits its function, an effect which may be related to CS nephrotoxicity.

Interferometers: equivalent sine condition and pseudoholographic properties.

We show experimentally how an interferometer, which in its current use does not have pseudoholographic properties, acquires them when the working conditions lead to the nonfulfillment of the equivalent sine condition.

Method of adjusting an interferometer.

We propose an experimental method for the adjustment of an interferometer by amplitude division illuminated with a spatially incoherent source.

Cyclosporine augments renal mitochondrial function in vivo and reduces renal blood flow.

The in vivo action of cyclosporine A (CS) on rat renal cortical mitochondria was investigated. CS (30 mg.kg-1.day-1) given orally to rats for 30 days caused an augmentation of renal mitochondrial oxidative phosphorylation. The ADP-stimulated respiratory rate was increased by 37.0% with glutamate plus malate as respiratory substrates (P less than 0.025) but not with succinate-supported respiration, indicating enhancement of mitochondrial complex I activity. This reaction may be a response to the 32.5% reduction of renal blood (P less than 0.005) in the CS-treated group, possibly serving to maximize ATP synthesis during ischemia. Ligation-induced decreases in renal blood flow also resulted in enhancement of mitochondrial complex I activity.

Effect of cyclosporine on steroidogenesis in rat Leydig cells.

Cyclosporine induces hypoandrogenism in adult male rats. In order to assess whether this effect of CsA may be due to a direct inhibitory effect on Leydig cell function, CsA (0, 50, 500, and 5000 ng/ml) was added to a collagenase-dispersed mixed Leydig cell preparation and incubated with and without hCG (0, 0.1, 0.3, 1.0, 3.0, and 10.0 ng/ml). Testosterone (T) production, mitochondrial cholesterol side chain cleavage (CSCC) and microsomal 17,20-desmolase enzyme activities in Leydig cells were determined after 3 hr of incubation. In the absence of CsA, stimulation of T production was maximal (about 16-fold) with 1.0 ng/ml hCG. With 50 and 500 ng/ml CsA there were no changes in either the hCG-stimulated T levels or the two enzymatic activities. However, 5000 ng/ml CsA significantly (P less than 0.05) reduced the hCG (1 ng/ml)-stimulated T levels, CSCC and 17,20-desmolase activities. The high dosage of CsA (5000 ng/ml) also caused a significant decrease in cell viability (P less than 0.05) during the incubation period. These effects of CsA were not due to cremophor EL, the CsA vehicle. This in vitro data indicate that high dosages of CsA (greater than or equal to 5000 ng/ml) appear to have a cytotoxic effect on rat Leydig cells that results in a decrease in T production. However, lower doses of CsA (less than 500 ng/ml) do not have any direct inhibitory effect on the rat Leydig cells, suggesting that the hypoandrogenic effect of in vivo CsA in rats is not due to any direct effect on the testis.

Cyclosporine inhibits testosterone biosynthesis in the rat testis.

To determine whether the immunosuppressive agent cyclosporine (CsA) has an effect on testicular androgen function in the male rat, four groups of adult animals were treated daily for 28 days with either orange juice or three doses of CsA (7.5, 15, or 30 mg/kg X day). Twenty-four hours after the last dose of CsA, the animals were killed and the following parameters were measured: testis, seminal vesicle, and ventral prostate weights; serum levels of CsA, creatinine, testosterone (T), and LH; and intratesticular levels of pregnenolone, progesterone, 17 alpha-hydroxyprogesterone, androstenedione, and T. There were no differences between the control (orange juice) and the three CsA-treated groups with respect to serum creatinines and testis, seminal vesicle, and ventral prostate weights. Serum T decreased significantly in the 15 and 30 mg/kg CsA-treated groups. The intratesticular T level decreased significantly only in the 15 and 30 mg/kg CsA-treated groups. In the 15 and 30 mg/kg CsA-treated groups, the intratesticular pregnenolone, progesterone, and 17 alpha-hydroxyprogesterone levels all showed a significant decline compared to controls. There was no significant change in the androstenedione levels in any of the CsA-treated groups. To determine whether the decrease in T production by the testis exposed to CsA is via inhibition of the hypothalamic-pituitary axis, serum LH was measured in all four groups. Serum LH decreased significantly only in the 15 and 30 mg/kg CsA-treated groups. These data suggest that oral CsA administration in doses greater than 15 mg/kg X day results in diminished intratesticular T production that appears to be mediated via inhibition of pituitary LH function.

Two biochemically distinct populations of histaminocytes separated by isokinetic sedimentation of dispersed rat gastric cells.

Two populations of histaminocytes, with different sedimentation rates (SR), were separated by a computer developed isokinetic gradient using dispersed rat gastric mucosal cells. Histamine content, histidine decarboxylase (HDC) activity and incorporation of radiolabelled histidine metabolites were used to assess the migration of specific cells throughout the gradients. One histaminocyte population, with cells of lower SR, contained high HDC activity and undetectable levels of histamine, whereas the other population, with cells of higher SR, contained lower HDC activity and high concentration of histamine. Both types of histaminocytes incorporated 3H-histidine metabolites. Electron microscopy showed that the fractions containing histaminocytes with lower SR had 3.5 times more endocrine ECL cells than the original population of dispersed fundic cells and lacked A and D cells, whereas the fractions with histaminocytes of higher SR were associated with a 2.7 times higher concentration of A and D cells and with a 7.7 times higher ratio of a variety of partial cells with a distinct mitochondrial morphology. These results are consistent with prior novel information regarding the separation of two populations of rat histaminocytes using different sedimentation techniques.

Separation and characteristics of two histaminocytes from rat gastric mucosa.

To determine the properties of rat gastric cells involved in histamine metabolism (histaminocytes), fundic mucosa was enzymatically dispersed prior to separation by sedimentation methods. The distribution of histamine content, histidine decarboxylase (HDC) activity and incorporation of radioactive histidine metabolites were used to determine the characteristics of various populations of gastric cells. All activities measured, as well as most of the dispersed gastric cells, occurred in a narrow range of density between 1.083 and 1.091 g/ml. Velocity sedimentation showed that two populations of histaminocytes can be distinguished. One population has a higher sedimentation rate, suggesting a larger size, contains histamine, HDC activity and incorporates radioactive metabolites. Another population, in fractions with lower sedimentation rates, contains little histamine, has a higher HDC activity than the previous population and also incorporates radiolabelled histidine metabolites. For the first time, two populations of viable histaminocytes have been separated that differ in their biochemical properties.

Agglutinins and proteins in the earthworm, Lumbricus terrestris, before and after injection of erythrocytes, carbohydrates, and other materials.

Agglutinin activity and total protein concentration in earthworm coelomic fluid were determined 24 hours after injecting different erythrocyte types and carbohydrates. Agglutinin titers increased from 14 to 1216 after a single injection of erythrocytes. At the same time, protein concentrations increased by variable amounts, suggesting an indirect correlation between increased agglutinin titer and protein concentration. To understand the nature of erythrocyte determinants responsible for inducing agglutinins and other proteins, separate groups of earthworms were injected with different carbohydrates. At 24 hours, coelomic fluid was assayed for agglutinin titer and protein concentration. The injection of different carbohydrates, amino acids, nucleotides and protein (BSA), like erythrocytes, also increased protein concentration and agglutinin titers. Changes in the protein concentration and composition of coelomic fluid were studied by standard and bidimensional immunoelectrophoresis. Different patterns and numbers of components were found before and after injection. At least two different components were present after injecting carbohydrates or erythrocytes, which may be related specifically to the agglutinins. Clearly, earthworms can synthesize and shed these molecules at rapid rates into the coelomic fluid. These molecules may be involved in earthworm defense.

Splenic and thymic histamine forming enzyme activity and weights following organ allograft and tumor cell transplantation.

Kinetic of the increasing activity of histamine forming enzyme--histidine decarboxylase in host spleen and thymus, following kidney and heart allografting and after tumor cells transplantation is presented.

Decreases in histamine forming enzyme activity of non-metastasizing fibrosarcomas in hamsters with progressive tumor growth.

A marked and progressive decrease in the activity of the histamine forming enzyme, histidine decarboxylase (HDC), of tumors was found to be associated with the progressive growth of SV-40 virus induced and transplanted syngeneic non-metastasizing fibrosarcomas in inbred LSH Syrian hamsters. Histamine forming enzyme activity was highest in the smallest tumors (p < .005) and in the tumors with the slowest growth rate (p < .005, r - 0.84). Tumor histamine forming enzyme activity was highest for each interval of animal exposure to inoculated tumor cells in those animals which had limited their tumor growth to the smallest tumor size. These findings suggested a local anti-inflammatory effect of progressive tumor growth. Induced local inflammation by repeated intratumor injections of bradykinin markedly elevated tumor histamine forming enzyme activity above expected levels for tumors of the same size in a small group of individual animals which were sampled at random from a larger group of animals which were being studied for the tumor growth kinetics effects of repeated intralesional injections of bradykinin. Tumor histamine forming enzyme activity was highest in those animals which were managed by the frequency of injection and dose schedules which were found in the tumor growth kinetics study to be most effective in limiting tumor growth. These findings suggested that the observed anti-inflammatory effects of progressive tumor growth may be reversed by locally induced inflammation at the tumor site with beneficial effects on tumor growth.