SpermCheck Fertility, an immunodiagnostic home test that detects normozoospermia and severe oligozoospermia.

BACKGROUND: A simple and inexpensive home sperm test could be of considerable value to couples attempting to conceive and to men curious about their fertility potential. A two-strip lateral flow immunochromatographic diagnostic device that allows men to evaluate their sperm count at low cost in the privacy of their own homes is described. METHODS: The ability of SpermCheck Fertility to predict sperm counts obtained using a hemacytometer procedure based on standard World Health Organization methodology was assessed. Test results obtained by lay users were also compared with those obtained by trained laboratory professionals, and the ease of use of the device was evaluated in consumer studies. RESULTS: A total of 225 semen samples were analyzed in the method comparison, and the performance of SpermCheck Fertility was excellent with over 96% of all samples correctly classified as normozoospermic (> or =2 x 10(7) sperm/ml), oligozoospermic (5 x 10(6)-2 x 10(7) sperm/ml) or severely oligozoospermic (<5 x 10(6) sperm/ml). Consumer studies with 164 lay users demonstrated that SpermCheck Fertility was easy to use. Lay users and laboratory professionals agreed 95% of the time when reading the same test independently. Overall, the correct response rate on a 20-question survey about the test was over 97%. CONCLUSIONS: SpermCheck Fertility is a simple and reliable immunodiagnostic test that can quickly inform men as to whether their sperm count is normal, low or very low. This home test can assist couples in deciding whether to seek comprehensive clinical evaluation of the fertility status of the male partner.

Hyperosmolality in intraluminal fluids from hamster testis and epididymis: a micropuncture study.

Intraluminal fluids from hamster seminiferous tubules, rete testis, and caput, corpus and cauda epididymidis were obtained in vivo by micropuncture. Rete testis fluid is isosmolar with serum. Fluids from the seminiferous tubules and all sites in the epididymis are hyperosmolar.

Influence of surgically induced varicocele on testicular blood flow, temperature, and histology in adult rats and dogs.

Varicocele had been repeatedly implicated as a cause of infertility in selected men, although neither a causal relationship nor a mechanism has been documented. The purpose of this investigation was to create a varicocele model in animals and to study the subsequent alterations in testicular physiology. Secondary dilatation of the left internal spermatic vein was achieved either by partial ligation of the left renal vein in rats and dogs or by surgical destruction of the valve of the left testicular vein in a second group of dogs. 1 mo after partial ligation in the rats and 3 mo after partial ligation or valve destruction in the dogs, testicular blood flow was measured using Strontium 85 (SR-85)-labeled microspheres (15 +/- 1.1 micrometer). Intratesticular temperature was measured with a Bailey needle probe thermometer and biopsies were obtained for histologic sections. Mean testicular blood flow in milliliters per minute per 100 g was significantly greater in the partially ligated rats; right testis control 26 +/- 2, left testis control 24 +/- 2 compared to right testis experimental 35 +/- 3, left testis experimental 35 +/- 4 (p less than 0.02). Dogs undergoing either partial vein ligation or valve destruction showed similar increases in mean testicular blood flow; right testis control 8 +/- 1, left testis control 8 +/- 1 vs. right testis experimental 16 +/- 3, left testis experimental 18 +/- 4 (p less than 0.01). The mean difference between intratesticular and intraperitoneal temperature in control rats was significantly higher (4.02 +/- 0.25 degrees C right testis, 3.77 +/- 0.14 degrees C left testis), than rats who underwent partial vein ligation (right testis 2.14 +/- 0.09 degrees C, left testis 2.34 +/- 0.12 degrees C) (p less than 0.001). Control dogs also had a significantly higher mean difference between intratesticular and rectal temperatures; (right testis control 3.61 +/- 0.42 degrees C, left testis control 3.60 +/- 0.40 degrees C) than the partially ligated or valve destruction dogs (right testis 2.31 +/- 0.17 degrees C, left testis 2.67 +/- 0.32 degrees C) (p less than 0.05). In addition, histologic evaluation revealed abnormalities in spermatogenesis in some of the animals. Thus, venous dilatation secondary to partial vein ligation or testicular vein valve obliteration is followed by large bilateral increases in testicular blood flow in these two species. A consequence of this increased flow is an elevation in bilateral testicular temperature, which it is postulated, leads to impaired spermatogenesis in some of the animals. In selected men varicocele may impair spermatogenesis by a similar physiologic mechanism.

Depression of fractional sodium reabsorption by the proximal tubule of the dog without sodium diuresis.

The effect of infusions of hyperoncotic solutions on fractional sodium reabsorption by the proximal tubule of the dog was studied by the recollection micropuncture method. Tubule fluid to plasma inulin concentration ratios were measured for identified proximal tubule segments before and after infusion of 25% albumin or dextran solutions. Results were compared with changes in fractional reabsorption during saline diuresis. Plasma volume increased 66% +/- SE 5.8 after infusion of albumin solution and 94% +/- SE 8.2 after infusion of dextran solution. Fractional sodium reabosorption by the proximal tubule was depressed after infusion of both of these hyperoncotic solutions. Nevertheless, changes in sodium excretion after infusion of albumin and dextran were small. In contrast, after infusions of isotonic sodium chloride solution, which increased plasma volume 61% +/- SE 5.8, a decrease in fractional reabsorption of 50.7% +/- SE 7.2 was associated with large changes in sodium excretion.

Androgen binding proteins of testis, epididymis, and plasma in man and monkey.

Androgen-binding protein (ABP) has been found in the cytosol of testicular and epididymal homogenates of several sub-primate species. In those species which had the plasma androgen binding protein, testosterone-estradiol-binding globulin (TeBG), ABP and TeBG were found to be physically similar. We investigated the possibility that ABP might exist in monkey and man using the cytosol of testicular and epididymal homogenates and aspirates obtained by direct micropuncture of the rete testis. In polyacrylamide gel electrophoresis, pH 7.8, testicular and epididymal cytosols of monkey and man were found to contain several binding proteins of different size and net charge that bind dihydrotestosterone. These binding proteins were either indistinguishable from TeBG or could be related to TeBG as size and/or charge isomers. No ABP was detectable in up to 200 mul of monkey rete testis fluid obtained by direct micropuncture, though ABP is detectable in as little as 5 mul of rat rete testis fluid. The data suggest that the ABP's detected in the testicular and epididymal cytosols in monkey and man represent isomeric forms of plasma TeBG, and their presence in testicular cytosol most likely derives from blood contamination.

On the androgen microenvironment of maturing spermatozoa.

Adult anesthetized male rats were submitted to in vivo micropuncture of the seminiferous and epididymal tubules and reproductive tract vasculature to obtain fluids for analysis of testosterone, 5 alpha-dihydrotestosterone, and androgen-binding protein (ABP). Androgen and ABP concentrations were determined by RIA. The highest concentrations of testosterone (73.14 +/- 5.12 ng/ml) were in testicular interstitial fluid. A significant downhill concentration gradient exists between testosterone concentrations in testicular interstitial fluid and seminiferous tubule fluid (50.24 +/- 2.26 ng/ml); another significant decrease occurs between seminiferous tubule fluid and rete testis fluid (17.85 +/- 2.11 ng/ml). 5 alpha-Dihydrotestosterone concentrations were highest in intraluminal caput epididymidal fluids (58.73 +/- 6.48 ng/ml) as were ABP concentrations (33.30 +/- 2.40 mu leq/microliter). Intraluminal sperm concentrations were also determined, and from these data, fluid reabsorption by the efferent ducts and epididymal tubules were calculated. Eighty-nine percent of the fluid leaving the testis is reabsorbed between the rete testis and caput epididymidis, and 96% is reabsorbed between rete and cauda. It was calculated that large losses of androgen and ABP also occur from the lumen of the excurrent duct system. These losses may be due to metabolism, diffusion from the lumen, or uptake by cells.

Rapid regression of pituitary prolactinomas during bromocriptine treatment.

Therapy for large prolactinomas remains controversial. Surgery is often unsuccessful in restoring endocrine function to normal. However, medical therapy with bromocriptine, a dopamine agonist, not only suppresses PRL levels, but may also lead to a reduction in tumor size. Previous reports have demonstrated radiographic evidence of tumor regression only after 3 or more months of bromocriptine therapy. We have now documented, for the first time, objective evidence of extremely rapid reduction in tumor size in two patients harboring large PRL-secreting pituitary tumors (mean pretreatment serum PRL levels, 2350 and 3900 ng/ml) who were prospectively treated with bromocriptine (7.5 mg/day) in preference to surgical intervention despite marked visual impairment in one of the patients. After 2 and 6 weeks of therapy, respectively, marked reduction in tumor size was demonstrated radiographically in both patients. Headache, visual acuity, and visual fields had improved after only 3 days. Although the mechanism of bromocriptine's antitumor activity is unclear, we believe that a large prospective trial to study the effects of bromocriptine therapy on the size of PRL-secreting macroadenomas is urgently needed to determine whether medical therapy should become the primary modality of treatment to reduce tumor size as well as restore endocrine function.

Possible biological mechanisms for a relationship between vasectomy and prostatic cancer.

Four hypotheses have been reviewed, each of which might serve as a hypothetical biological explanation for a relationship between vasectomy and prostate cancer. The endocrine hypothesis is the only one of these with any firm data to support it, although the majority of the available data does not lend credibility to that theory. The other hypotheses are purely speculative with no hard data to support them. In conclusion, it seems highly unlikely, but not impossible, that there is a biological mechanism supporting a relationship between vasectomy and prostate cancer.

Prevention of recurrent urinary tract infections in girls.

Eighteen girls between the ages of 3 and 13 years--with a history of at least three culture-documented episodes of bacteriuria in the previous year, but without radiologic evidence of major urinary tract abnormality--were placed on a double-blind, crossover study comparing the effectiveness of nitrofurantoin macrocrystals against a placebo in preventing the recurrence of bacteriuria. Each child was placed on a daily low dose of nitrofurantoin (1.2 to 2.4 mg/kg/day) or an identical-appearing placebo for six months. Each child was then placed on the opposite capsule for a similar period. There were 35 episodes of bacteriuria (4.2 episodes/patient/yr) in the patients taking the placebo, which compared with a rate of 3.8 episodes/patient/yr during the year prior to the study. Only two episodes (0.2 episodes/patient/yr) occurred in the patients taking the drug. The difference in the rate of recurrent bacteriuria between the girls on placebo and on medication is significant at the 0.01 level using the Wilcoxin matched-pairs test. There were no adverse reactions to the drug. Nitrofurantoin macrocrystals in a single daily low dose appear to be a safe, effective method of preventing recurrent bacteriuria in girls at high risk.

Antisperm autoantibody responses to vasectomy and vasovasostomy in Fischer and Lewis rats.

Antisperm autoantibodies were studied in Fischer and Lewis strains of rats after either vasectomy, vasectomy followed one month later by vasovasostomy, or sham operations. The time course of antibody response to sperm protein autoantigens was assayed by Western blot analysis of sera obtained at intervals up to 3 months. Rats of both strains responded to immunization with isologous spermatozoa with production of high titer hyperimmune sera. Sera from vasectomized Fischer rats showed antisperm antibodies on Western blots, but bands were stained with less intensity and frequency than for Lewis rats. In both Fischer and Lewis strains, major protein autoantigens were observed at 75-83, 68-71, 63, 57, 51, 41, and 21-23 kDa, lending support to the hypothesis that there is a set of dominant sperm autoantigens recognized by a consensus of postvasectomy rat sera. The lesser response of Fischer rats to vasectomy was not due to absence of dominant postvasectomy sperm autoantigens in Fischer sperm extracts, nor was it attributable to inability of Fischer rats to mount an immune response to these antigens, since immunization with isologous sperm was successful in raising antibodies to the dominant autoantigens. Vasovasostomy did not result in a general decrease in antisperm antibodies, and reactions to some antigens actually increased.

Appearance of 'natural' antisperm autoantibodies after sexual maturation of normal Lewis rats.

Serum antisperm antibodies were assessed quantitatively with an ELISA in normal male Lewis rats at intervals between ages 10 and 128 days, spanning the onset of puberty. Antisperm antibodies rose between 56 and 91 days, and were significantly higher in 91- and 128-day old rats than at earlier intervals. The animals underwent normal pubertal development as indicated by increases in weights of the seminal vesicles and ventral prostate. The rise in antisperm antibodies correlated temporally with events in the postnatal development of the male reproductive system, with the increase in antisperm antibodies most closely following the time when spermatozoa reach the epididymis and proximal vas deferens at approximately 56 days. The observation that serum antisperm antibodies increased only after sexual maturation suggests that some differentiation antigens of sperm are processed and presented to the immune system under normal circumstances in this strain. Western blot analysis showed that the sera from normal postpubertal Lewis rats bound several proteins, including bands of > 100, 82-75, 78, 68, 65, 63, 54-55, 42, 37, 35, 26, and 20-22 kDa. The majority of these autoantibodies were sperm-specific as shown by the absence of comigrating bands in western blots of somatic tissue extracts, although antibodies in postpubertal sera recognized certain other proteins in somatic tissues. Several protein autoantigens, defined by sera from postpubertal animals, matched dominant autoantigens recognized by antibodies produced in response to vasectomy, prepubertal vas obstruction, or immunization with spermatozoa. This finding indicates that the antisperm antibody responses following sperm immunization, vasectomy or prepubertal vasal obstruction represent accentuation of an autoantibody response to sperm that develops normally following puberty.

Temporal recognition of sperm autoantigens by IgM and IgG autoantibodies after vasectomy and vasovasostomy.

Temporal patterns of IgM and IgG autoantibodies to sperm proteins were studied by western blot analysis at intervals after bilateral vasectomy, vasectomy followed one month later by vasovasostomy, or sham operations. Responses were detected to eight major autoantigens at 21-23, 36, 41, 51, 57, 63, 68-71 and 75-83 kDa, by study of staining patterns of sequential serum samples from individual animals and by analysis of the incidence of reaction to each protein. The four lower molecular weight antigens (21-23, 36, 41 and 51 kDa) provoked mainly IgG responses. The strongly stained set of higher molecular weight antigens (57, 63, 68-71 and 75-83 kDa) tended to show more clearly defined temporal patterns of IgM followed by IgG response, including a high incidence of IgM antibody at the 2-week interval. Three of the larger peptides (57, 63 and 68-71 kDa) appeared highly immunogenic, since some reactions were detected even in sham-operated rats. The classical patterns of IgM and IgG antibody responses to the majority of the dominant sperm autoantigens are in accord with the hypothesis that vasectomy mimics immunization with spermatozoa. The high incidence of IgM antibodies in the earliest sample, taken 2 weeks after vasectomy, suggests that the initial immunizing event takes place within about a week after the operation. Vasovasostomy did not bring about a decrease in antisperm antibodies. Instead, some animals demonstrated an increased reaction to certain antigens after reversal of vasectomy, even though the vasovasostomies were anatomically successful.

PIP: The production of antisperm antibodies is common subsequent to vasectomy and antisperm antibodies frequently persist following the reversal of vasectomy. The number of such antibodies may even increase after vasovasostomy. Using adult male Lewis rats, the authors analyzed the dominant autoantigens which evoke IgM and/or IgG autoantibodies after vasectomy by western blotting (WB) methods, the temporal patterns of IgM and IgG autoantibodies to specific sperm proteins, and the influence of vasovasostomy upon IgM and IgG antisperm autoantibodies. The temporal patterns were studied by WB at intervals after bilateral vasectomy, vasectomy followed 1 month later by vasovasostomy, and fake operations. Responses were detected to 8 major autoantigens of 21-23, 36, 41, 51, 57, 63, 68-71, and 75-83 kDa through the study of staining patterns of sequential serum samples from individual animals and by analysis of the incidence of reaction to each protein. The 4 lower-molecular-weight antigens provoked mainly IgG responses, while the strongly stained higher-molecular-weight antigens showed more clearly defined temporal patterns of IgM followed by IgG response, including a high incidence of IgM antibody at the 2-week interval. The peptides of 57, 63, and 68-71 kDa seemed to be highly immunogenic, since some reactions were detected even in rats which received only a fake operation. Results support the hypothesis that vasectomy mimics immunization with spermatozoa, while the high incidence of IgM antibodies in the earliest sample, taken 2 weeks after vasectomy, suggests that the initial immunizing event occurs within approximately 1 week after the operation. Vasovasostomy caused no decrease in antisperm antibodies.

Post-obstruction rat sperm autoantigens identified by two-dimensional gel electrophoresis and western blotting.

Although antisperm autoantibody responses to obstruction of the male reproductive system have been documented, information on the nature of the cognate sperm autoantigens has been limited. In the present study, the patterns of sperm autoantigens recognized by sera from rats after obstruction of the vas deferens or epididymis were studied by high resolution two-dimensional (2-D) gel electrophoresis and western blotting. Comparisons of patterns of autoantigens stained on 2-D western blots of sera from prepubertal vasectomy, prepubertal epididymal ligation and adult vasectomy groups revealed both similarities and differences. Sera from sham-operated animals showed no detectable reaction or much lighter staining of a small number of spots. Visualization of sperm autoantigens on 2-D western blots supported the hypothesis that there is a relatively small set of sperm proteins that can be regarded as dominant post-obstruction sperm autoantigens because they are recognized by multiple post-obstruction sera. The 2-D analysis revealed previously undetected distinctions in the autoantigens recognized after adult and prepubertal vasectomy, as well as variations with the site of obstruction. These differences in the response may be due in part to changes in antigens of spermatozoa in different parts of the tract and at different ages, as well as variations in exposure of sperm cell proteins to the immune system resulting from the sites of spermatic granulomas. Preparative 2-D gels and western blotting with post-obstruction sera are now being used to identify specific sperm autoantigens by microsequencing of selected proteins.

Effects of vasectomy on the epididymis.

Common principles can be discerned in the response of the epididymis to vasectomy, despite species differences. Increases in the size and number of lysosomes are the most frequent changes in the epididymal epithelium. The presence or absence of additional alterations such as changes in the height of the epithelium may be related to variations in distensibility of the vas deferens and epididymis. Direct measurements by micropuncture of epididymal and seminiferous tubule hydrostatic pressure indicate that, contrary to dogma, increased pressure in the distal epididymis after vasectomy is not generally transmitted to the seminiferous tubules. The epididymal interstitium shows microscopic changes indicative of chronic inflammation, with infiltration of macrophages, lymphocytes, and plasma cells, and rats with these lesions have higher antisperm antibody levels than animals lacking epididymal changes. Macrophages and neutrophils may enter the duct through the epididymal epithelium, at sites of rupture of the duct, and in the efferent ductules. Cyst-like spermatic granulomas occur in virtually all species where the epididymis or vas deferens ruptures with escape of spermatozoa. The sites and timing of granuloma formation may depend on the mechanical properties of the tract in different species, and they are probably important in the immune response to vasectomy. Postvasectomy sera in Lewis rats recognize a consensus repertoire of dominant autoantigens that closely resembles the antigens bound by sera from rats immunized with isologous spermatozoa. There are multiple routes for disposal of the sperm that continue to be produced after vasectomy.

PIP: The changes in the epididymal epithelium, luminal contents, inflammation in the epididymal interstitial tissue, and gross epididymal alterations after vasectomy are described. Studies of vasectomy and its reversal by vasovasostomy in the rat as a model system conducted over the decade prior to 1993 were reviewed. Common principles can be discerned in the response of the epididymis to vasectomy, despite species differences (rat, rabbit, guinea pig, and hamster). Increases in the size and number of lysosomes are the most frequent changes in the epididymal epithelium. The presence or absence of additional alterations such as changes in the height of the epithelium may be related to variations in distensibility of the vas deferens and epididymis. In the guinea pig and hamster the intratubular hydrostatic pressure in the seminiferous tubule was significantly lower (p 0.001) than in the caput epididymis. Direct measurements by micropuncture of epididymal and seminiferous tubule hydrostatic pressure indicate that, contrary to dogma, increased pressure in the distal epididymis after vasectomy is not generally transmitted to the seminiferous tubules. The epididymal interstitium shows microscopic changes indicative of chronic inflammation, with infiltration of macrophages, lymphocytes, and plasma cells, and rats with these lesions have higher antisperm antibody levels than animals lacking epididymal changes. Cyst-like spermatic granulomas occur in virtually all species where the epididymis or vas deferens ruptures with escape of spermatozoa. The sites and timing of granuloma formation may depend on the mechanical properties of the tract in different species, and they are probably important in the immune response to vasectomy. Postvasectomy sera in Lewis rats recognize a consensus repertoire of dominant autoantigens that closely resembles the antigens bound by sera from rats immunized with isologous spermatozoa. There are multiple routes for disposal of the sperm that continue to be produced after vasectomy.

The venous anatomy of experimental left varicocele: comparison with naturally occurring left varicocele in the human.

OBJECTIVE: To determine the effect of experimental left varicocele on the anatomy of the veins serving the rat testis and to compare that anatomy to known patterns of vascular drainage from the human testis with and without varicocele. DESIGN: Vascular maps were made of the effluent vessels from the rat testis in control animals and those with a 30-day experimental left varicocele. Consensus maps were arrived at and these were compared to published reports of the pertinent venous anatomy in humans with and without varicocele. SETTING: Research laboratory. RESULTS: The major route of blood leaving the rat testis was confirmed to be the spermatic vein, but nine common collaterals were also found to exist. Four of these collaterals became more pronounced with experimental varicocele as did several dilated perineal veins. These latter vessels all led to the iliac vein. The vasculature of the rat experimental varicocele model shares some important anatomical features with human varicocele anatomy. CONCLUSIONS: Varicocele in humans and in the rat model causes a redistribution of blood flow from a route primarily out the spermatic vein to routes leading to the iliac vein. The redistribution is similar but not identical.

Vasectomy and prostate cancer: the evidence to date.

PIP: A 1993 editorial in "Fertility and Sterility," accompanying publication of two cohort studies by Giovannucci et al. indicating a positive association between vasectomy and prostate cancer, noted the observed association could have resulted from chance, bias, or a causal association. There is strong potential for bias in the selection of study participants and in the additional medical attention received by sterilized men. Men who undergo vasectomy may have different life-style characteristics than those who do not. Meta-analyses of prostate cancer risk have calculated higher odds ratios in studies judged to have inadequate selection of controls and possible detection bias than in more methodologically rigorous studies. Overall, a review of the research evidence reveals inconsistent study findings, weak strength of any observed association, and little biologic plausibility for a vasectomy-prostate cancer link.^ieng

Micropuncture studies of the motility of rete testis and epididymal spermatozoa.

The effect of cyclic adenosine 3':5'-monophosphate (cAMP) and caffeine on the motility of spermatozoa obtained in vivo by micropuncture from the rat rete testis, caput epidiymidis, and cauda epididymidis was studied. Spermatozoa from all sites were immobile in their native fluid. Rete testis spermatozoa were not motile under any experimental conditions. After dilution in salt solution, some caput sperm exhibited circular motion, whereas most cauda sperm swam progressively. Dextrose enhanced the motility of sperm from both epidiymal sites. Caffeine further increased the motility of epididymal sperm. Dibutyryl cAMP and cAMP stimulated caput spermatozoa but had no effect on cauda spermatozoa.

Micropuncture and microanalytic studies of the effect of vasectomy on the rat testis and epididymis.

Micropuncture techniques adapted for in vivo use in the male reproductive tract were used to study the effect of vasectomy on the concentration and morphology of spermatozoa in the seminiferous tubules and ductus epididymidis of the rat. Regardless of surgical technique, 85% of all rats which had previously under vasectomy developed a speratic granuloma at the proximal end of the ligated vas deferens. Vasectomy did not affect the weights of the ipsilateral (vasectomized) testes. Vasectomy without granuloma formation resulted in an elevation in the weight of the ipsilateral epididymis and an increase in the concentration of spermatozoa in the ipsilateral cauda. Vasectomy complicated by granuloma formation caused a significant increase in the ratio of the spermatocrit in the seminiferous tubule to that in the caput. In the vasectomized rat without granuloma, significantly more abnormal spermatozoa were in the caput than in the cauda; in the normal rat, the concentrations of abnormal spermatozoa in the two regions were not significantly different. Vasectomies with and without granuloma formation are distinct phenomena and should be investigated separately.

Micropuncture and microanalytic studies of the rat testis and epididymis.

Micropuncture techniques developed for the study of renal physiology have been adapted for investigation of the male reproductive tract. Ultramicro specimens were obtained in vivo from the tubules of the rat testis and epididymis. These samples were analyzed for sperm morphology and concentration. The new methods developed to conduct these studies are discussed in detail. The mean in vivo spermatocrits were 0.411 plus and minus 0.029, 0.355 plus and minus 0.019, and 0;731 plus and minus 0.028 in the seminiferous tubule, caput epididymidis, and caudal spermatocrit was significantly higher than the spermatocrit in the caput or seminiferous tubule. The percentages of abnormal spermatozoa in the caput and cauda were 5.5% plus and minus .7% and 4.3% plus and minus .6%, respectively.

Metabolic effects of unilateral orchiectomy on the guinea pig testis.

Six months after unilateral orchiectomy, there was a significant increase in the RNA and DNA content of contralateral testes as compared with the testes of age-matched normal guinea pigs. The ratio of RNA to DNA was not affected by orchiectomy, suggesting that the compensatory growth was secondary to hyperplasia rather than hypertrophy. Tritiated thymidine uptake by the contralateral testis was elevated at 2 weeks and 2,4 and 6 months after orchiectomy, confirming that increased metabolic activity occurred in the remaining testis after hemicastration.