If both kidneys are removed from one partner of a parabiotic pair of rats, the urinary bladder of the operated animal atrophies while that of the intact partner hypertrophies ( 1 ) . The present investigation has been undertaken to find out if this hypertrophy results from voidings of increased frequency or increased volume. It would appear to be a little of both.Materials and Methods. Sprague-Dawley rats (Charles River CD@) were parabiosed as littermates weighing less than 100 g. They were joined together from shoulder to hip with confluent peritoneal cavities. The animals were allowed to reach maturity, and during the course of their first year both kidneys were removed from the right partner via dorsolateral incisions. At this time, both animals were approximately the same size, but the nephrectomized partner tended to lose weight thereafter.The pattern of micturition was monitored in these animals before and after nephrectomy to determine how the frequency and volume of urination were affected by the operation. Animals were placed in metabolism cages, and their urine was carried through plastic tubes to a fraction collector equipped with 60 centrifuge tubes per revolution. At 15-min intervals, the fraction collector shifted a new collecting tube into position. I n this way, the apparatus could be allowed to run for up to 15 hr without attention. Urine was collected in the above manner from parabiotic rats for periods of 1 wk at a time. The urine tubes were replaced twice a day, and the amounts of urine weighed and recorded for each voiding. Urine was collected for 1 wk from each parabiotic pair prior to nephrectomy and, thereafter, 1 Supported by NIH research grants GM18805 and HE 13659. for the lst, Sth, loth, and 15th weeks. A total of 27 pairs of rats were analyzed in this way, but owing to the premature demise of some animals the data reflect diminishing returns to 17 pairs by the 5th week, 9 by the 10th week, and 7 by the 15th week.Results have been expressed in terms of frequency of urinations, amount of urine per voiding, and total urine produced. The latter two items were corrected for changes in body weights during the course of the experiment, and all data have been calculated on a percentage basis of the original preoperative figures. Prior to nephrectomy, when both partners of a parabiotic pair were urinating into the same tube, it has been necessary to correct the results to take into account occasional simultaneous urinations in a given 15-min interval. Thus, the number of tubes with urine in them per 24-hr period was recalculated according to the formula N = n + ( n 2 / 9 6 ) , where N is the actual number of urinations, n is the observed number, and 96 is the number of 15-mh intervals in a 24-hr period. I t was not necessary to make this correction postoperatively, since only the intact partner would be urinating at that time.Animals were sacrificed at the end of the 15th postoperative week. Those that died prematurely were autopsied whenever possible. Rats were cut apart, and their body w...
Experiments on hypertrophy of the testis have been carried out by Lipschutz (1922) who stated there was accelerated growth of the contralateral testis which rapidly reached maximum weight, but that no true hypertrophy occurred after unilateral orchidectomy. Grant (1955) stated that an increase in testicular volume occurred after unilateral orchidectomy in three albino rats. Shellabarger (1963) stated there was no increase in testicular weight after removal of a single testis. Being an endocrine organ, the interstitial cells, including Leydig cells, of the remaining testis should reflect the effects of unilateral castration. Since spermatogenesis is hormonally controlled, the seminiferous tubule might be expected to respond by enhancing gamete production as do solitary remaining ovaries after unilateral spaying. The present work was designed to re-examine the above observations. One hundred and fifty Sprague-Dawley rats weighing 80 to 100 g were used in the experiments. The animals were divided into three groups. The control group (Group 1) consisted of fifty rats, which were weighed and kept for 4 weeks, and then killed and re-weighed at autopsy. The testes were also removed and weighed.Group 2 consisted of fifty rats, each of which was subjected to right unilateral orchidectomy. These were killed 4 weeks later and weighed. The remaining testis was removed, weighed, fixed in Zenker's solution, sectioned at 6 \ g=m\ thickness, and stained with haematoxylin and eosin.Group 3 also consisted of fifty rats, each of which was subjected to right unilateral orchidectomy. Testosterone cypionate, 0-05 ml, was injected twice a week subcutaneously for a total of 10 mg testosterone weekly. These rats were then killed 4 weeks later and weighed. The remaining testes were weighed and fixed, and then sectioned and stained with haematoxylin and eosin.The value was calculated by testicular weight over body weight of each animal (TW/BW in Table 1). All the testes were sectioned at right angles to their longitudinal axes at the widest point and a complete cross-section count of both the tubules and interstitial cells was made. The tubular diameters were then measured.The average pre-operative body weight was 87 g for the rats in Group 1, 82 g for those in Group 2, and 83 g for those in Group 3, while the average weight at autopsy was 236 g, 212 g and 200 g, respectively.The average weight for the left testis of rats in Group 1 at autopsy was 1-30 g, while the average weight of the remaining testis in Group 2 was 1-27 g, 537
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