Spontaneous mutant frequency of lacZ gene in spleen of transgenic mouse increases with age

Spontaneous mutant frequency of lacZ gene in spleen of transgenic MutaTM mouse was examined at different ages. It was (3.2 +/- 1.3 (SD)) x 10(-5) at newborn and increased almost linearly with age up to (8.3 +/- 1.8) x 10(-5) at one year. Since the mutation of the gene is not likely to be subject to selection in vivo, the data support the idea that spontaneous mutation takes place throughout aging process and accumulates with age if not selected out by cell death.

Carboplatin-based combination chemotherapy for testicular cancer: relationship among administration dose of carboplatin, renal function and myelosuppression

Carboplatin (CBDCA), a derivative of cis-diamminedichloroplatinum, has low renal and neural toxicity. The dose-limiting factor of this agent is myelosuppression. We experienced various degrees of myelosuppression, when the dose of CBDCA was determined by the body surface area (BSA) in CBDCA-based combination chemotherapy for testicular cancer. Calvert demonstrated that the dose of CBDCA administered should be adjusted by renal function, because CBDCA was excreted through the glomerulus. We report the relationship among 3 factors; the administration dose of CBDCA, renal function and the degree of myelosuppression. We treated 6 patients with testicular cancer. A total of 22 courses of CBDCA-based combination chemotherapy was performed. The area under the curve (AUC) was calculated by the following formula, which was demonstrated in Calvert's study. CBDCA dose = AUC x (GFR + 25), GFR; glomerular filtration rate. The degree of myelosuppression was examined. All chemotherapy courses were divided into 2 and 3 groups according to BSA and AUC, respectively. WBC and Plt reduction rates and nadir counts were significantly correlated with AUC, and showed no significant relationship to the dose determined by BSA. This study revealed that the degree of myelosuppression was closely related with AUC, which reflects the renal function.

Differential cytotoxic effects of mizoribine and its aglycone on human and murine cells and on normal and enzyme-deficient human cells

The growth inhibitory mechanisms of mizoribine, an immunosuppressive imidazole nucleoside used clinically to inhibit rejection reactions after renal transplantation and in the treatment of systemic lupus erythematosus and rheumatoid arthritis, were studied in human and murine cells. We found that (a) human cells were 20- to 60-fold more resistant than murine cells to both mizoribine and its aglycone, (b) adenine phosphoribosyltransferase (APRT)-deficient human cells were resistant to aglycone but not to mizoribine, (c) hypoxanthine phosphoribosyltransferase (HPRT)-deficient human cells were at least 100-fold more sensitive to both mizoribine and aglycone, and (d) the decrease in intracellular GTP broadly paralleled the cytotoxicity in each case. Therefore, data obtained from studies using non-human tissues should be interpreted carefully before clinical application. Results indicate that the growth inhibitory effect of the aglycone but not of mizoribine is mediated by APRT, and depletion of guanine nucleotides is responsible for the effects of both drugs. Our data also suggest that the drugs may reduce mutant HPRT-deficient somatic cells in vivo, and may cause enhanced adverse reactions in HPRT-deficient individuals. The drug may have altered effects in patients receiving other purine or pyrimidine analogs.

[An analysis of familial prostate cancer]

BACKGROUND

Clinical and pathological features of familial prostate cancer patients were examined.

METHODS

We compared 7 pairs (14 patients) of familial prostate cancer patients (Group F) with those of 1741 prostate cancer patients diagnosed in around Gunma Prefecture between 1987 and 1993 (Group G). Relative survival rates were compared because the average age was different in two groups.

RESULTS

In Group F and Group G, age at diagnosis ranged from 54 to 86 and 47 to 97 years old, and the averages were 68.1 +/- 8.5 (S.D.) and 74.2 +/- 8.3, respectively. The average age tended to be younger in Group F. The ratio of early stage cancer tended to be higher and that of poorly differentiated cancer tended to be lower in Group F. The 3- and 5-year relative survival rate was 82.4% and 57.6% in Group F, and 84.3% and 73.9% in Group G, respectively. The 5-year survival rate tended to be lower in Group F, but almost no difference was observed between two groups on the whole. In Group F, of 6 patients whose causes of death were clear, 4 (66.7%) died of prostate cancer, while in Group G, of 398 patients whose causes of death were elaar, 224 (56.3%) died of prostate cancer. Family history of other cancer sites was positive in 3 of 6 families in Group F.

CONCLUSIONS

Familial prostate cancer patients tended to be young, in early stage and low ratio of poorly differentiated cancer.

Histological and immunohistochemical changes after transurethral balloon laser hyperthermia in the canine prostate

Transurethral balloon laser hyperthermia (TUBAL-H) for the prostate was performed in a canine model. Eleven normal and hyperplastic prostates were heated at between 40 to 45 degrees C for 30 min. Compared to the pretreatment weight, the prostatic weight significantly increased immediately after treatment and significantly decreased at 4 weeks later, but was not significantly different after 8 weeks. Histologically, shedding of epithelial cells was observed immediately after treatment, although, coagulonecrotic tissue was not seen. After 8 weeks, atrophic changes of epithelial cells were observed at the inner portion of the prostate. By immunohistochemical analysis, epithelial cells expressing apoptosis related antigen (Ley) were observed at the inner portion of the prostate from immediately after treatment until 4 weeks later. The atrophic epithelia and the expression of apoptosis in the prostate gland were pathological changes induced by TUBAL-H. From the present data, it is suggested that TUBAL-H combined with radiation or administration of anti-cancer drugs may be effective for prostate cancer.

Diagnostic significance of prostate specific antigen and the development of a mass screening system for prostate cancer

PURPOSE

The significance of prostate specific antigen (PSA) in the mass screening for prostate cancer was investigated.

MATERIALS AND METHODS

A total of 4,375 PSA, digital rectal and transrectal ultrasonographic examinations was performed on 3,526 subjects.

RESULTS

Among the 3 modalities, PSA had the highest sensitivity (80.4%) and positive predictive value (45.1%). We established age-specific reference PSA ranges for normal Japanese men, and demonstrated the significance of PSA density and PSA velocity.

CONCLUSIONS

The significance of PSA as a prostate cancer screening modality should be evaluated across multiple age ranges and in combination with previous PSA data and/or prostate volume.

Prostate-specific antigen in mass screening for carcinoma of the prostate

BACKGROUND

Prostate-specific antigen (PSA) has various advantages over prostatic acid phosphatase (PAP) as a marker for prostate cancer, but its role in prostate cancer mass screening remains controversial. We measured serum PSA in addition to serum PAP determination and digital rectal examination (DRE) in our mass screening program to assess the usefulness of PSA for prostate cancer mass screening.

METHODS

Serum PSA and PAP measurements and DRE were performed in 1249 patients in mass screening for carcinoma of the prostate in 1989 and 1990. Thirteen cancers were diagnosed. We calculated the mean plus standard deviations (2SD) of the PSA and PAP values of men without cancer, and assessed the usefulness of PSA for prostate cancer screening by using these figures as the upper limit of normal.

RESULTS

The number positive for PSA, PAP and DRE were 39, 36 and 48, respectively. If our screening had been performed without DRE, three cancers would have remained undetected, and the number would have been the same if performed without PSA. If the screening had been performed without PAP, on the other hand, no cancers would have remained undetected. The sensitivities of PSA and PAP were 54% and 23%, respectively. The screening detection rate with DRE and PSA was 0.88%, and with DRE and PAP was 0.64%.

CONCLUSIONS

Measurement of serum PSA values with adjustment of the cut-off value was considered more useful than PAP in mass screening for prostate cancer.

Functional role of coronary collaterals with exercise in infarct-related myocardium

We evaluated the regional myocardial blood flow in collateral dependent infarct-related areas to examine the functional role of coronary collaterals. Regional myocardial blood flow was measured by positron emission tomography with 13N-ammonia at rest and during low-grade exercise (bicycle ergometer fixed at 25 W for 6.5 min). The study was performed in 24 subjects, consisting of 19 patients with prior myocardial infarction, and five normal individuals. Regional myocardial blood flow was calculated using the radioactivity in myocardial tissue measured by positron emission tomography and the radioactivity in arterial blood. Concerning the infarct related area, the exercise caused myocardial blood flow to decrease by 18.4% (P < 0.01) in the collateral-dependent areas (n = 8) of angiographically positive collaterals, and to increase by 14.4% (P = not significant) in the areas (n = 10) of negative collaterals. Four patients in whom the myocardial blood flow in all walls, including the normal areas, decreased with exercise were excluded from this evaluation. Myocardial blood flow in collateral-dependent infarct-related areas appeared to decrease transiently by low-grade exercise. Our results suggest that collaterals increase the incidence of exercise-induced ischemia, but may protect the infarct related but viable myocardium from necrosis.

Decreased immunoreactive inhibin and increased FSH levels in cryptorchidism after orchidopexy

The blood FSH level is often high in patients with severe testicular disorders including cryptorchids. To examine whether inhibin is involved in the increase in FSH we measured immunoreactive inhibin, FSH, LH, and testosterone in 17 patients after orchidopexy. FSH was extremely high (20 mIU/ml or above) in 3 patients. The inhibin level was significantly lower (P < 0.01) in these 3 patients (6.47 +/- 2.19 IU/ml; mean +/- SEM) than in the other 14 patients (14.31 +/- 3.96 IU/ml). All 3 high-FSH patients had azoospermia. Testosterone and LH were normal in one of them. Even considering problems involved in the inhibin assay, the high FSH levels are considered to reflect reductions in the blood inhibin level due to Sertoli cell dysfunction. These findings suggest that inhibin plays an important role in the suppression of FSH at least in some patients after orchidopexy.

Disulfide bond formation and secretion of Escherichia coli heat-stable enterotoxin II

The Escherichia coli heat-stable enterotoxin II (STII) is a typical extracellular toxin consisting of 48 amino acid residues, of which 4 are cysteine. There are two disulfide bonds, one between Cys-10 and Cys-48 and one between Cys-21 and Cys-36. We examined the involvement of DsbA in the formation of the disulfide bonds of STII and the role of each in the secretion of STII. A dsbA mutant was transformed with a plasmid harboring the STII gene, and STII was not detected either in the cells or in the culture supernatant. Reducing the level of STII brought about the dsbA mutation restored by introducing the wild-type dsbA gene into the mutant strain. These results showed that DsbA is involved in forming the disulfide bonds of STII and that STII without these disulfide bonds is degraded during secretion. We substituted these four cysteine residues in vivo by oligonucleotide-directed site-specific mutagenesis. The amino acid sequence of the purified STII (C48S) and pulse-chase studies revealed that two intermolecular disulfide bonds must be formed to be efficiently secreted and that cleavage between amino acid residues 14 and 15 is probably the first step in the proteolytic degradation of STII.

[The effects of antiandrogen TZP-4238 on plasma testosterone and LH and steroidogenesis in rat and canine testis]

TZP-4238 suppresses plasma testosterone in humans, but its action on the androgen biosynthesis pathway has not been established. Therefore, we researched the testicular testosterone level and the testosterone biosynthesis pathway in vitro in rats before and after receiving a single or continuous oral dose of TZP-4238. The total testosterone fell to 60% of the basal level within 3-8 hr (p < 0.05) and then returned to the control concentration by 24 hr after a single administration of 32 mg/kg. The alteration of the plasma testosterone level correlated well with that of the intratesticular level, which was decreased to 50% at 3-8 hr and recovered to the control level by 24 hr. However, the decrement of the plasma LH level at 3-8 hr after a single oral administration was slight and it then returned to the original level at 12 hr. During the 8 weeks of daily administration of 0.5 mg/kg of TZP-4238 or chlormadinone acetate to dogs, the plasma testosterone levels were slightly lower than the basal extent. In vitro experiments were conducted on the rat testis using the exogenous precursor steroids 20 alpha-hydroxycholesterol, pregnenolone and progesterone, in various steps leading to the biosynthesis of testosterone. Trilostane acted at 3 beta-hydroxysteroid dehydrogenase (50% inhibition concentration, IC50 was 1 microM), ketoconazole inhibited the 17 alpha-hydroxylase, and C20, 22- and C17, 20-lyase activities, with an IC50 of 1-50 microM. Cyproterone acetate inhibited both the 3 beta-hydroxysteroid dehydrogenase (IC50;50 microM) and C17, 20-lyase. On the other hand, TZP-4238 exhibited a weaker inhibition of 3 beta-hydroxysteroid dehydrogenase (IC50; 100 microM) than cyproterone acetate, but not of hydroxylase and lyase. Though TZP-4238 did not inhibit the increased testosterone level induced by hCG, trilostane markedly inhibited the effect induced by hCG.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clear cell sarcoma extending into the inferior vena cava]

A 6-year-old boy who had been diagnosed as having Wilms tumor at the prior hospital was admitted to our hospital for investigation of a right flank mass and macrohematuria in October 1990. Magnetic resonance imaging showed Wilms tumor of the right kidney extending into the inferior vena cava. Right radical nephrectomy, lymphadenectomy and thrombectomy were done on October 30th, 1990. Pathological findings indicated clear cell sarcoma of the kidney. One week after the operation, radiotherapy and chemotherapy with actinomycin D (ACTD), vincristine sulfate (VCR), doxorubicin hydrochloride (DXR) and cyclophosphamide (CPM)) were started according to the protocol by National Wilms Tumor Study (NWTS) III. However, he died of bone metastases and pneumomycosis on October 13th, 1992. Clear cell sarcoma of the kidney (CCSK) is a rare tumor accounting for about 4-5% of Wilms tumors. This is the first report on CCSK with tumor thrombus in Japan.

Epidemiological characteristics of prostate cancer in Gunma Prefecture, Japan. Gunma University Urological Oncology Study Group

BACKGROUND

Prostate cancer is rare in Asia, but the number of patients is increasing in Japan. We conducted an epidemiological study of prostate cancer in Gunma Prefecture, Japan, to investigate the trends and characteristics of the disease.

METHODS

The subjects were 1,411 prostate cancer patients newly diagnosed between 1985 and 1992, and 656 patients who died from prostate cancer between 1981 and 1992. The incidence and mortality rates were calculated by year, demographic region and age.

RESULTS

The yearly incidence rate showed an increase but the mortality rate showed no marked fluctuations. There was no significant difference between urban and rural districts in either incidence or mortality rate. The incidence rate tended to be high in the northern part of the prefecture, but no marked variation in mortality rate was seen. The incidence and mortality rates in districts with a history of manganese mining were high compared to those in districts without mining. In contrast, the incidence and mortality rates in districts with a history of zinc mining were comparatively lower. Both incidence and mortality rates showed a marked increase with age. The age-specific incidence showed a double logarithmic relationship to age.

CONCLUSIONS

The increase of the yearly incidence rate might be due to changes in lifestyle and environmental factors, improved diagnostic techniques, and increased awareness among the general public regarding prostate disease. Further investigation is needed to clarify the pattern and the causes of regional differences in the incidence and mortality rates. The possibilities that managanese and zinc might be related to prostatic carcinogenesis are suggested.

Ultraviolet-radiation-induced chemical reactions through one and two-photon absorption processes in GeO(2)-SiO(2) glasses

Photochemical reactions in 10 GeO(2)-90 SiO(2) glass induced by irradiation with excimer lasers (KrF, 5.0 eV, XeCl, 4.0 eV) and a Hg lamp (4.9 eV) were examined. The irradiation with excimer lasers generated two types of paramagnetic defect, an electron-trapped center associated with fourfold coordinated Ge ions and a self-trapped hole center on bridging oxygen. Taking the optical band gap (~7.1 eV) of the glass obtained in this work and the power density of laser pulses [10-90 mJ/(cm(2) pulse), pulse duration 20 ns] into account, we concluded that these centers were formed by band-to-band excitation by two-photon absorption process. On the other hand, the lamp illumination ( 16 mW/cm(2)) caused the formation of Ge E' centers from preexisting oxygen-vacancy-type defects by the one-photon absorption process. These two kinds of reaction proceed independently, depending on the power densities of UV beams, at least in our experimental condition.

Changes in prostatic thickness and the location of ejaculatory ducts in autopsy prostates

OBJECTIVE

To measure prostatic thickness and the depth of ejaculatory ducts from the urethral surface to prevent ejaculatory duct damage during transurethral balloon laser thermotherapy.

MATERIALS AND METHODS

In 47 prostates obtained at autopsy, the prostatic thickness and the depth of ejaculatory ducts from the urethral surface were measured in eight directions from the centre of the urethra.

RESULTS

The depth of ejaculatory ducts was approximately 6 mm from the urethral surface regardless of prostatic weight. Increase in prostatic weight was associated with increase in the thickness in all directions except the posterior one; the thickness ranged from 9 to 20 mm. The posterior thickness at the level of the transition zone was 10 mm regardless of prostatic weight.

CONCLUSION

When benign prostatic hypertrophy is treated transurethrally, using laser or microwave equipment, care should be taken to avoid heating the posterior region of the prostate.

Relation between cardiac index and regional myocardial blood flow in the non-infarcted wall using PET with 13NH3 in healed myocardial infarction

It is not clear whether there is any relationship between cardiac output and myocardial blood flow in the infarcted heart. We measured regional myocardial blood flow (RMBF) quantitatively by positron emission tomography (PET) with 13N-ammonia at rest in 18 patients with prior myocardial infarction. RMBF was calculated using the radioactivity in myocardial tissue measured by PET and the radioactivity of arterial blood. Cardiac output was determined by the dilution method using 13NH3 as an indicator, and the relation between cardiac output and RMBF was evaluated at the same time during PET study. There was a good linear correlation between cardiac index (C.I.) and mean RMBF in non-infarcted myocardium (r = 0.45, p < 0.05), and non-infarcted size (r = 0.74, p < 0.01). There was an even better linear correlation between C.I. and sigma RMBF (representing the product of mean RMBF and non-infarcted size) as follows: y = 0.016x + 1.94, r = 0.76 (p < 0.001). It was indicated that the value of C.I. may be related to RMBF of non-infarcted myocardium and its size.

Metallothionein binding zinc inhibits nuclear chromatin decondensation of human spermatozoa

Nuclear chromatin decondensation (NCD) of the human spermatozoa was induced by 1% sodium dodecyl sulphate (SDS). NCD of the spermatozoa induced in healthy and fertile men was significantly stronger and at higher rates than that in infertile men. In 1% SDS with 6 mM zinc chelating EDTA, metallothionein (MT) significantly enhanced NCD in a healthy man. In contrast MT alone significantly inhibited sperm NCD. Sperm NCD rate induced by 1% SDS in 10 infertile men was significantly inhibited by adding 75 or 750 micrograms ml-1 of MT. By adding 1.5 mM zinc, MT at concentrations of 0.75, 7.5, 75, or 750 micrograms ml-1, enhanced the inhibitory effect of 1.5 mM zinc. This suggested that thiols in the MT could, when liberated from zinc by zinc-chelating EDTA, induce sperm decondensation by cleaving stabilizing S-S bridges and that zinc bound to MT could exert a chromatin stabilizing effect mediated by the zinc dependent type of chromatin stability. The present study suggested that zinc bound to MT, which is secreted mainly from the prostate gland, is one factor that contributes to the chromatin stabilizing effect of human prostatic fluid.

[Clinical analysis of ureteral injuries]

Six cases of ureteral injuries were analyzed. Two cases were male and 4 cases were female. The right side was affected in 1 case and the left in 5 cases. The affected portion was the uretero-pelvic junction in 1 case and lower iliac vessels in the other cases. Five cases were iatrogenic injuries in surgical or gynecological pelvic operation, and the other was due to blunt trauma. Intraoperative diagnosis was made in 4 cases. Drain leakage led to diagnosis in one case and pyelonephritis in another. Ureteroureterostomy was performed in 2 cases, pyeloureterostomy in 1 case, ureteroneocystostomy with psoas hitch in 1 case, Boari bladder flap in 1 case and simple suture in 1 case. 4-0 or 5-0 Dexon with an atraumatic needle was used for all anastomoses. Except for case 1, who died of the recurrence of carcinosarcoma, renal functions were preserved in all patients during the follow-up period ranging from 5 months to 7 years 8 months.

Transurethral balloon laser hyperthermia for chronic non-bacterial prostatitis: a clinical trial

Transurethral balloon laser hyperthermia (TUBAL-H) was performed on five patients with chronic non-bacterial prostatitis who failed to respond to conventional treatment administered for more than two years. The prostatic interstitial temperature during treatment was measured and the safety and efficacy of this treatment was assessed. TUBAL-H was performed at a target temperature of 43 degrees C (5 mm depth) and at a laser power of 30 watts with urethral cooling for 20 min in the first three patients and for 30 min in the remaining two patients. The prostatic interstitial temperature at a depth of about 5 mm from the urethral surface ranged from 40.5 to 43.0 degrees C during treatment. The temperature of the urethra ranged from 31.5 to 39 degrees C and that of the rectum remained below 39.5 degrees C. After treatment, no abnormal findings were noted in any of the hematological and biological tests carried out, including prostatic specific antigen. The leukocyte count in expressed prostatic secretions fell to less than five cells per high-power field in four of the five patients after three months. A complete improvement in symptoms was observed in one patient, partial improvement in three, and no improvement in one. Based on these results, TUBAL-H was considered to be safe and a suitable treatment for patients with chronic prostatitis.

Endocrine environment of benign prostatic hyperplasia: prostate size and volume are correlated with serum estrogen concentration

Estrogen plays an important role in the development of benign prostatic hyperplasia (BPH), as has been shown in both experimental and clinical studies. T determine the endocrine environment of BPH, serum total testosterone (Total-T), free testosterone (Free-T), and estradiol (E2) conceptions were measured, and the relationship between these levels and prostate size and volume was analyzed. Blood samples were collected from subjects who attended the mass screening for prostate disease performed by our institute. No significant correlations were found between Total-T levels, Free-T levels, and prostate size, as determined by digital rectal examination. However, E2 levels and the ratios for E2 levels and the ratios for E2/Total-T and E2/Free-T were significantly correlated with prostate size. To confirm these relationships, prostate volume was calculated from transrectal ultrasonographic images. E2 levels and these two ratios were, indeed, highly correlated with prostate volume. These results suggest that an estrogen-dominant environment plays an important role in the development of BPH.

Assessment of adrenal surgery on creatinine clearance in patients with phaeochromocytoma

Sequential changes in creatinine clearance (Ccr) were determined in 14 patients undergoing operation for phaeochromocytoma. All patients had been given alpha-adrenergic antagonists 2 weeks before surgery. In the younger group (mean age 40 +/- 2 years), Ccr improved following adrenal surgery. Urinary concentrations of epinephrine, norepinephrine and total catecholamines correlated inversely with Ccr. A similar inverse relationship was noted between tissue norepinephrine concentration expressed as microgram/g and Ccr to a lesser extent. In older patients (mean age 69 +/- 2 years) Ccr remained unchanged by this surgical procedure. No significant correlations were found between both parameters in the older group. It appears reasonable to presume that excessive amount of catecholamine plays an important role in the impairment of Ccr in relatively young patients with phaeochromocytoma, but other possibilities as regards the sequence of this phenomenon must be pursued in older patients.

[Clinical study on 78 cases of testicular tumor]

Seventy eight patients with testicular tumor were treated in our hospital between 1982 and 1992. Of 78 patients, 74 had germinal cell tumor (seminoma in 47 patients and non-seminoma in 27), and the other 4 had 3 malignant lymphoma and 1 rhabdomyosarcoma. Ages ranged from 1 to 67 years with the average of 36.1. The age of the patients with seminoma was significantly higher than that of patients with non-seminoma. Most patients complained of painless swelling of the scrotal content, but some patients complained of testicular pain, fever, and so on. Those who complained of such symptoms had significantly worse prognosis than those who had only painless scrotal swelling. Patients with non-seminoma visited us about 4.9 months after the onset of their symptoms and 12.1 months in seminoma. Clinical stages were more progressive in non-seminoma than in seminoma. Inguinal orchiectomy was performed followed by irradiation, chemotherapy, retroperitoneal lymph node dissection or thoracotomy. Recurrence developed in 6 patients and the other 7 patients died of progressive disease within 2 years from the first attendance. The 2-year survival rate calculated by the Kaplan-Meier method was 81 and 70% in seminoma and non-seminoma, respectively, and 100, 88, 63, 75, and 22% in stage I, IIA, IIB, IIIO and IIIA, B, C, respectively.

Synergistic effects of estrogen and androgen on the prostate: effects of estrogen on androgen- and estrogen-receptors, BrdU uptake, immunohistochemical study of AR, and responses to antiandrogens

To investigate the synergistic effects of estradiol (E2) and testosterone (T) on prostate growth, castrated Wistar rats were treated with 1 mg/day of T or with 1 mg/day of T and 0.01 mg/day of E2 for 6 weeks. The weight of the prostate in T + E2-treated rats was significantly higher than that in T-treated and normal rats, parallel with the bromodeoxy-uridine (BrdU) labeling index (LI). Nuclear androgen receptor (AR) content in the T + E2 group was significantly higher than that in the T group. But they were lower than that in normal rats. And there were no significant differences between the groups in nuclear estrogen receptor (ER) content. Immunohistochemical studies with the AR antibody revealed positive staining in the prostatic epithelium and stromal cells in the normal, T-treated, and T + E2-treated animals. However, castration led to loss of staining. Response to steroidal antiandrogens was also determined. Antiandrogen treatment abrogated the increases in nuclear AR content and BrdU LI, and prevented immunohistochemical staining. These results suggest that AR and ER, which were measured in this study, were not indicators of prostatic proliferation. We further need to investigate other factors, including other types of receptors, growth factors involved in epithelial-stromal interaction, and so on.