[Study of trough type audiogram of sudden hearing loss]

We investigated 974 patients with sudden sensorineural hearing loss who consulted the otolaryngological service of Hamamatsu University Hospital and four affiliated hospitals from 1984 to 1992. Among them, we selected 569 new cases showing a pure tone average of 31 dB or more at 250 Hz, 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz on the affected side in the initial audiometry performed within 14 days after the onset of sudden sensorineural hearing loss. The 569 patients consisted of 13 with acoustic neuromas (SHLANs), 493 with idiopathic sudden sensorineural hearing loss (ISHLs) and 63 others. Ten of the 13 SHLANs and 40 of the 493 ISHLs showed the trough type audiogram on the initial examination. We defined the 10 cases as the Trough AN group and the 40 as the Trough ISHL group. Statistical analysis of the difference in pure tone averages at 5 frequencies between the 2 groups demonstrated that the mean hearing losses at 125, 250 and 500 Hz of Trough AN were significantly less than those of Trough ISHL. This study demonstrates that the trough type audiogram, especially a slight low tone loss, shown in patients with sudden sensorineural hearing loss was a significant finding suggesting the presence of acoustic neuroma.

[Continent urinary reservoir using dilated renal pelvis of non-functioning pelvic kidney in a girl with cloacal exstrophy]

We performed construction of continent urinary reservoir in an 8-year-old girl with cloacal exstrophy who had double stoma of ileostomy and colon conduit. Preoperative evaluation revealed non-functioning right kidney with severely dilated renal pelvis and calyxes in her pelvis. Urinary reservoir was constructed using detubularized colon segment which had been used as the urinary conduit and dilated renal pelvis of non-functioning pelvic kidney. Using Mitrofanoff's principle, continent catheterizable channel was also made of the anterior wall of the renal pelvis. Postoperative course was uneventful. Reservoir capacity increased to 350 ml one and half year postoperatively and she is almost dry with clean intermittent catheterization 5 times a day. Dilated upper urinary tract is one of the ideal material for bladder enlargement that avoids the complication associated with the use of gastrointestinal tract.

Electrocardiographic nature of restored sinus rhythm after Cox maze procedure in patients with chronic atrial fibrillation who also had other cardiac surgery

OBJECTIVE

To characterise heart rate variability and high frequency components of restored sinus rhythm after the maze procedure. The maze procedure for chronic atrial fibrillation may prevent thrombotic events and improve the quality of life. However, the electrocardiographic nature of restored sinus rhythm after the maze procedure has not been fully elucidated.

PATIENTS AND METHODS

Between March 1993 and August 1995, 104 consecutive patients undergoing the maze procedure in combination with other cardiac surgery were studied. There were 100 long-term survivors (78 with mitral valve disease, 9 with aortic valve disease, 8 with congenital heart disease, and 5 others). Twenty age-matched patients with mitral valve disease who were in normal sinus rhythm preoperatively were enrolled as a control group. 30 days after surgery, the presence of arrhythmias and the circadian changes of heart rate variability were estimated by ambulatory electrocardiographic monitoring and the filtered P duration was evaluated by signal-averaged electrocardiogram.

RESULTS

Restoration of sinus rhythm was observed in 73 of 100 cases. Subjects were classified into three groups according to their postoperative ambulatory electro-cardiographic monitoring findings: patients in group 1 (n = 73) (1a: 58 regular sinus rhythm; 1b: 15 sinus rhythm with frequent premature atrial contractions (> 1000/day); patients in group 2 (n = 21) still had persistent atrial fibrillation; and patients in group 3 (n = 6) required permanent pacemaker implantation because of sick sinus syndrome. The success rate of restoration of sinus rhythm was 88.3% if left atrial diameter was small (< 65 mm). Circadian changes in the low frequency to high frequency power ratio in group 1a were significantly diminished compared with control group (P < 0.01). Furthermore, the filtered P duration in group 1a (150 (20) ms) and group 1b (158 (23) ms) were longer than in the control group (122 (11) ms) (P < 0.01).

CONCLUSIONS

The maze procedure may result in a decreased sinus response and non-uniform transmission of impulses in the atrium.

A multiple gastric ulcer case caused by cytomegalovirus infection

The patient was a 31 year old male complaining discomfort in the epigastrium. Endoscopy of the upper gastrointestinal tract indicated multiple gastric ulcers. Biopsy specimen taken from the ulcerous region indicated giant cells accompanying intranuclear inclusion bodies in the gastric mucosa. Since the patient tested positive to cytomegalovirus (CMV)-IgM antibody, he was assumed to have gastric ulcers caused by CMV infection. However, the patient was cured without the administration of antiviral agent because no definite immunodeficiency status was observed. The result of present study indicated that endoscopic biopsy is useful for diagnosing gastrointestinal lesion attributable to CMW infection.

[A case of postrenal acute renal failure in a neonate with bilateral ectopic ureters]

A male neonate was referred to our institute after the placement of right nephrostomy because he presented syndrome of acute renal failure and bilateral hydronephrosis. Voiding cystourethrography revealed bilateral vesicoureteral reflux (right.; grade I, left.; grade V), and renal scintigraphy revealed left hypodysplastic kidney. Endoscopy revealed bilateral ectopic ureters; posterior urethra on the right and bladder neck on the left. We performed bilateral ureterocystoneostomy with bilateral ureteral folding. Postoperative course was uneventful, and the serum creatinine improved to the level of 0.5 mg/dl 6 months after the intervention.

Glucose metabolism in the cortical and subcortical brain structures in multiple system atrophy and Parkinson's disease: a positron emission tomographic study

The brain glucose metabolism was studied by PET with 18F-FDG in 11 patients with multiple system atrophy (MSA) and 12 patients with idiopathic Parkinson's disease (PD). Seven of the 11 MSA patients were diagnosed as having olivopontocerebellar atrophy, two had striatonigral degeneration, while two demonstrated Shy-Drager syndrome. The glucose metabolic rates for each region in the PD patients showed no difference from the normal controls. The frontal, temporal and parietal cortical glucose metabolic rates and the caudate, the putaminal, the cerebellar and the brainstem glucose metabolic rates in the MSA patients decreased significantly from the controls. The atrophy of the cerebellum and the brainstem in the MSA patients were scored by MRI. The cerebellar and brainstem glucose metabolism in the MSA patients decreased as the atrophy score in such regions advanced in each group; however, some patients with no atrophy showed a decreased glucose metabolism. Although the cerebellar and the brainstem glucose metabolism decreased in all MSA patients, such a decrease was not observed in the SND patients. The decrease in the glucose metabolism for the non-cortical regions in the MSA patients seems to be due to a diffuse depletion of the neurons not restricted to the nigrostriatal neurons. Deafferentation to the cerebral cortices seems to result in a decreased cortical metabolism. The differences in the glucose metabolism between MSA and PD as assessed by PET may be caused by the pathophysiological differences between MSA and PD, and such differences therefore appear to be useful when making a differential diagnosis between MSA and PD. The relative sparing of the brainstem and cerebellar glucose metabolism is considered to be a feature of patients with SND.

[Ectopic ureter opening in the vestibulum without urinary incontinence: a case report]

A case of ectopic ureter without urinary incontinence despite its ureteral orifice in the vestibulum is reported. A 2-year-and-9-month-old female was referred to our hospital with the pain of external genitalia, pollakisuria and macroscopic hematuria. Examination revealed a complete double system of the left upper tract with vestibular opening from the upper moiety. She did not show any signs of ureteric incontinence after the establishment of voiding habits. Because radioisotope (RI) scintigram showed apparent uptake in the upper half of the left kidney we performed left ureterocystoneostomy with psoas hitch procedure. We postulate that the incontinence mechanism is maintained when the running course of the ectopic ureter is through some portion of the urethral sphincter musculature. This is the 10th case reported in Japan.

[A case of bilateral testicular torsion in a neonate]

A case of testicular torsion in the newborn is presented. A 8-day-old infant with bilateral intrascrotal swelling since birth was referred to us. Bilateral testicular torsion was suspected and operation was carried out at the same day. We operatively found extravaginal torsion of the bilateral spermatic cord. The bilateral testis appeared extensively necrotic, but we repaired the torsion and performed bilateral orchiopexy because of bilateral torsion. We could not palpate well the bilateral testis in one year, probably due to an atrophy. Sixty-nine cases of testicular torsion in the newborn including our case from Japanese literatures were reviewed and discussed. Especially forty-seven cases were presented at birth.

[Results of antireflux surgery in infants with vesicoureteral reflux]

BACKGROUND

Due to the advancement of prenatal and postnatal ultrasound screening in addition to better understanding by pediatricians, more infants have been detected to have vesicoureteal reflux. There are still debates, however, about their management whether to take conservative or surgical treatment.

METHODS

We analysed clinical courses of 51 children with primary reflux undergoing antireflux surgery when they were under 1 year.

RESULTS

A total of 41 infants (80%) presented with febrile urinary tract infections. The first UTI was seen as early as 7th day after birth, with the average age of 2 months. Seven infants had hydronephrosis detected by prenatal ultrasound, and 2 were identified by neonatal screening ultrasonography. Sixty-eight of 86 reflux ureters (79%) showed high grade reflux (grade IV approximately V). All the other 18 ureters with mild to moderate grade of reflux except one accompanied with contralateral high grade reflux. One ureter with grade II reflux was associated with contralateral obstructed meganreter. Renal parenchymal abnormalities, either with scarring and/or small kidney, were identified in 64 kidneys (74%) at or before the reimplantation. The operation was done as early as 1 month-old with the average age of 5.6 months. Among the children, 24 (47%) underwent anti-reflux surgery before 6 month-old. Smallest infant weighted 2500 gr at the time of operation. Reimplantation was done by the Cohen transverse advancement technique in 75 ureters (87%). The modified Politano-Leadbetter method in 6 with Hutche's diverticulum, and the Glenn-anderson advancement method in 5 with moderate to mild reflux. Two dilated ureters were treated with folding of the intravesical segment. Follow-up voiding cystourethrogram of 49 children at 6 months revealed no evidences of persistent reflux. There were no patients with obstruction of reimplantation except one with slight upper-tract dilatation. One infant revealed new low grade contralateral reflux, and he is being observed. Two children presented pyelonephritis after the operation.

CONCLUSION

Our success rate of 100% in antireflux surgery enables us to continue our policy to perform early operative interventions in infants with high grade reflux. In addition to the meticulous and careful technique, the conditions for successful results include; 1) A through checkup of the lower tracts by VCG and endoscopy. 2) Find the better operative instruments for the small bladder. 3) Do not hesitate to perform the ureteral tapering. 4) Make good use of operative loupe.

Differential expression of platelet-derived endothelial cell growth factor (thymidine phosphorylase) in nonpolypoid and polypoid lesions of the colon

To clarify the relationship between angiogenesis and the early development of colon cancer, expression of platelet-derived endothelial cell growth factor (PD-ECGF), a known angiogenic and endothelial cell chemotactic factor, was examined in 119 human colon premalignant adenomas and colon carcinomas. Localization of PD-ECGF was assessed by immunocytochemistry in 70 nonpolypoid growth (NPG) lesions that represented 29 carcinomas (NPG carcinomas) and 41 adenomas (NPG adenomas) and 49 polypoid growth (PC) lesions that included 15 carcinomas (PG carcinomas) and 34 adenomas (PC adenomas). Simultaneously, the expression of tranforming growth factor alpha (TGF alpha) and epidermal growth factor receptor (EGFR) were examined in serial sections from these lesions. Twenty (68.9%) of 29 NPC carcinomas and 20 (48.7%) of 41 NPC adenomas exhibited positive staining for PD-ECGF, whereas 15 (100%) of 15 PG carcinomas and 27 (79.4%) of 34 PG adenomas expressed PD-ECGF. There was a statistically significant difference in the frequency of PD-ECGF expression between NPG adenomas and PG adenomas (p<0.01). In addition, the incidence of PD-ECGF expression was higher in PG carcinomas than in NPG carcinomas (p<0.05). Positive staining for TGF alpha and EGFR was detected in 14 (48.2%) and 10 (34.5%) of 29 NPG carcinomas, respectively, whereas, 17 (41.5%) and 13 (31.7%) of 41 NPG adenomas expressed TGF alpha and EGFR, respectively. A significant trend for coexpression of PD-ECGF and TGF alpha was detected in either NPG adenomas (p<0.05) or PG adenomas (p<0.01). These data demonstrate that PD-ECGF may be involved in the early stages of colon cancer development during the adenoma-carcinoma transition and additionally that angiogenesis which may be induced by PD-ECGF and/or TGF alpha could play an important role of colon cancer development.

Ipsilateral hemiplegia caused by right internal capsule and thalamic hemorrhage: demonstration of predominant ipsilateral innervation of motor and sensory systems by MRI, MEP, and SEP

A patient with a right internal capsule and thalamic hemorrhage showed ipsilateral hemiplegia. MRI at 10 months after the cerebral hemorrhage demonstrated Wallerian degeneration, which could be traced to the ipsilateral anterior funiculus at the cervical level. The findings of motor evoked potentials and somatosensory evoked potentials indicate a predominantly ipsilateral innervation of motor and sensory systems in this particular patient.

Differences in the reduced 18F-Dopa uptakes of the caudate and the putamen in Parkinson's disease: correlations with the three main symptoms

It has been reported that the F-Dopa (FD) uptake in patients with idiopathic Parkinson's disease (PD) decreased significantly in the caudate and putamen when compared to controls. The FD uptake severely decreased in the putamen, while it was relatively spared in the caudate nucleus. We also previously reported that atypical parkinsonism with no or little tremor showed a homogeneously reduced FD uptake in both the caudate and the putamen. In this study we evaluated the caudate and the putaminal FD uptakes in relation to the three main symptoms in PD. The FD uptake was measured by PET with 6-L-[18F]fluorodopa in 17 patients with PD. The caudate and the putaminal FD uptake ratios to the cerebellum at 120 min were evaluated. The caudate and the putaminal FD uptake ratios in the patients with PD decreased as their clinical stages advanced. These decreases also correlated with the degree of rigidity and bradykinesia. However, such decreases did not correlate with the degree of tremor. The caudate-putamen index (CPI)(%), which was calculated by a formula based on the difference in the uptakes of the caudate and putamen divided by the caudate uptake, indicated 11.6 +/- 3.6, 16.5 +/- 5.5 and 18.3 +/- 4.1 in the group of no, mild and moderate tremor, respectively, and increased as the degree of tremor advanced. The CPI in the group of moderate tremor significantly increased from that in the group of no tremor (P < 0.04). However, the CPI did not correlate with the clinical stage, the degree of rigidity or the degree of bradykinesia. The FD/PET study therefore effectively demonstrated the severity of the clinical symptoms of rigidity and bradykinesia in patients with PD in correlation with a decrease in the FD uptakes in the caudate and the putamen, and it also demonstrated that the severity of tremor might have a different mechanism from that of such other symptoms as rigidity and bradykinesia.

[Femoral testis: report of three cases]

Three patients were referred to our clinic with the chief complaint of emptiness of the right scrotal contents. Every physical examination in these patients revealed a little-finger-tip sized mass corresponding to the normal testis at the right side of the femoral region. Right orchiopexy by the dartos-pouch technique was successfully performed. On every surgical exploration of these patients, the gubernaculum was fixed to the femoral skin and the testis was found to be normal in size. Our cases are the 2nd, 3rd and 4th cases of femoral testis, reported in the Japanese literature.

[Accessory scrotum with lipoma: a case report]

A newborn male infant was referred to our clinic because of anomalies of external genitalia. The infant was born at term after a normal pregnancy and delivery, and was appropriate for gestational age. A tumor mass covered with scrotum-like skin on its tip was noticed in the right side of perineum between the scrotum and anus. The raphe, which ran along the midline at the penis and the normal scrotum, circumscribed the right side of this structure. Both testes had descended into the scrotum. The condition was associated with incomplete penoscrotal transposition. There was no other urological anomaly including lower urinary tract. Histological findings of the tumor indicated perineal lipoma, and the scrotum-like portion was diagnosed as an accessory scrotum. Thirty-one report cases of the accessory scrotum including our own were reviewed and discussed.

Transient cortical blindness following bypass graft angiography. A case report

Transient cortical blindness, an uncommonly recognized complication of cerebral angiography, is an exceedingly rare event after cardiac catheterization and angiography. This report describes a sixty-two-year-old patient who had transient cortical blindness following bypass graft angiography. In this case, the authors showed that cortical blindness was associated with the breakage of the blood-brain barrier (BBB) and an increase in vascular permeability rather than with primary cerebral circulatory insufficiency. When the possibility exists that an excess volume of contrast medium may enter the cerebral circulation as in this case, that is, following a coronary artery bypass graft (CABG) using the internal mammary artery (IMA), precautionary measures may be necessary such as changing the type of contrast medium to be used or decreasing the volume injected. When cortical blindness occurs, it is a serious clinical problem whether transient or permanent. Therefore, the circumstances leading to this complication should be understood to determine suitable treatment and management.

A possible mechanism for the increase in serum luteinizing hormone levels in male rats by oxolinic acid

Oxolinic acid (1-ethyl-1,4-dihydro-6,7-methylenedioxy-4-oxo-3- quinolinecarboxylic acid), an antimicrobial agent, raises the serum levels of luteinizing hormone (LH) and increases the incidence of testicular Leydig cell tumors in male rats. In the present study the mechanism by which serum LH levels are raised in male rats receiving oxolinic acid was investigated. Aged Wistar rats were fed a diet containing oxolinic acid at 0 or 3000 ppm for more than 4 weeks. There was no effect of oxolinic acid on either the maximal levels of serum LH after castration nor on the serum levels of LH stimulated with 1 microgram/rat of luteinizing hormone-releasing hormone (LHRH). The concentrations of testosterone in serum and testis were not changed by the treatment of oxolinic acid. In the in vitro organ culture, the testes of rats receiving oxolinic acid released testosterone in the same manner as the controls, in the presence or the absence of human chorionic gonadotropin (100 mIU/ml). The oxolinic acid-stimulated serum LH was not increased further by the daily administration of L-dopa (500 mg/kg/day, po, 7 days) and was blocked by the injection of a dopamine antagonist, haloperidol (2 mg/kg, ip). In a microdialysis study, oxolinic acid increased the extracellular concentration of dopamine in the preoptic area of hypothalamus. These findings suggest that a high dietary level of oxolinic acid elevates LH release from the anterior pituitary with an increase in LHRH, in part, by the excitatory input of a dopaminergic system in the preoptic area of rat hypothalamus.

[Urinary tract abnormalities associated with anorectal malformations]

Anorectal malformation (ARM) is often associated with urological problems such as congenital urogenital anomalies, recto-urinary fistula, neurogenic bladder due to vertebral anomalies and operative complications. We analyzed 57 cases of ARM and discussed about the management of associated urogenital anomalies during neonatal and infantile period. The incidence of urogenital anomalies was 85.7% in high type, 65.5% in intermediate type and 38.1% in low type. Among these urinary tract anomalies, VUR was most common and was documented in 38.6% of ARM patients. Renal dysplasia, PUJ stenosis, megaureter and urethral stenosis was also common in these patients. Renal dysfunction was documented in 5 cases (2 in high type, 2 in intermediate and 1 in low type), mainly due to VUR and renal aplasia. These results show the need for evaluation of urinary tract during the neonatal and early infantile period even in low type ARM. The management of urinary tract anomalies associated with ARM is firmly related with the management of ARM itself, and we must be closely in co-operation with pediatric surgeons.

Effects of repeated doses of compound E for 4 and 9 weeks on the male reproductive organs

Results of two toxicity studies of Compound E, which is an anticancer drug, on male reproductive organs and fertility by oral repeated dosing at dose levels of 12.5, 25 and 50 mg/kg/day for 4 and 9 weeks in rats were compared. After repeated dosing, the male fertility was studied by mating with untreated female animals. At the dose of 50 mg/kg/day in the 4-week study, Compound E significantly decreased testes weight and number of epididymal sperm, caused histopathological changes in the testis and epididymis characterized by decreased germ cells, but did not affect fertility. The dose of 25 mg/kg/day in the 9-week study caused reduction in epididymal weight and number of epididymal sperm and histopathological changes in the testis. The dose of 50 mg/kg/day in the 9-week study was lethal and caused more prominent toxic effects in the reproductive organs and loss of fertility. The present studies suggest that the order of sensitivity of parameters on male reproductive organs is as follows; histopathological examination = organ weight > number of sperm in epididymis > pregnancy index> copulation index. Further, 4-weeks repeated dosing is of sufficient duration to predict adverse effects of test compounds.

A new mutant rat with hyperbilirubinuria (hyb)

We have discovered mutant rats with hyperbilirubinuria at the laboratories of Eisai Co., Ltd., Gifu, Japan, and established a new inbred mutant strain, which was designated Eisai Hyperbilirubinuria Rat (EHBR/Eis). They show jaundice immediately after birth, and direct or conjugated hyperbilirubinemia throughout their life. The phenotypes are controlled by a single autosomal recessive gene, hyb with full penetrance. Affected homozygous males seem to have full reproductive capacity. On the other hand, the litter size of hyb/hyb females is significantly reduced at second parturition compared with that at first one. In order to maintain the strain efficiently and to produce both affected (hyb/hyb) and normal control (hyb/+) offspring at the same time, we have mainly been mating hyb/hyb males with hyb/+ females in establishing the inbred strain. We also report here the allele distribution of the EHBR/Eis strain.

A new mutant rat with turning behavior (Tur)

A new rat mutant with abnormal behavior has been found in a closed colony of Slc: SD. The affected rats turned around after their own tails beginning 4-5 weeks after birth, in response to extroceptive stimuli, such as sound or vibration. The behavior was more pronounced in younger animals. On gross observation, no alteration was found in the cerebrum, cerebellum, or anterior, posterior, or lateral semicircular canals. Light microscopic examination revealed no abnormality in the cerebrum or cerebellum. The trait was controlled by an autosomal dominant gene with incomplete penetrance (78.0%) when transferred to the WKY genetic strain background. It was named "turning" with the gene symbol Tur. A congenic strain was established, which was designated WKY/Eis-Tur.

A patient with Schinzel-Giedion syndrome and a review of 20 patients

The Schinzel-Giedion syndrome is characterized by severe midface retraction, multiple skull anomalies, clubfeet, and cardiac and renal malformations. So far, 20 patients have been reported. This is the first report of the syndrome demonstrated in Oriental patients. In surviving patients, severe growth and developmental deficiency is a common finding.

Differentiation of Langerhans cells from interdigitating cells using CD1a and S-100 protein antibodies

The present study shows that Langerhans cells can be differentiated from interdigitating cells at the light microscopic level. Superficial lymph nodes and skin taken from necropsies and the lymph nodes of dermatopathic lymphadenopathy (DPL) were used for this experiment. Sections of lymph node and skin were embedded using the acetone, methyl benzoate and xylene (AMeX) method and dendritic cells were immunostained with anti S-100 protein antibody (S-100, and OKT-6 (CD1a) using the restaining method. Langerhans cells in the skin were positive for both CD1a and S-100. Dendritic cells positive for both CD1a and S-100, and dendritic cells positive for S-100, but not for CD1a were observed in superficial lymph nodes. In normal superficial lymph nodes, there were more interdigitating cells than Langerhans cells. The majority of the dendritic cells in the DPL were Langerhans cells. We conclude that the S-100 and CD1a positive cells are Langerhans cells, and the S-100 positive-CD1a negative cells are interdigitating cells.

Species-specific mechanism in rat Leydig cell tumorigenesis by procymidone

To clarify the mechanism of species difference in the induction of testicular interstitial cell tumor (ICT, Leydig cell tumor) between rats and mice, male Sprague-Dawley rats and ICR mice were fed procymidone at dietary concentrations of 700, 2000 or 6000 ppm and 1000, 5000, or 10,000 ppm, respectively, for 3 months. The Leydig cell functions were evaluated by serum testosterone and luteinizing hormone (LH) levels, testosterone levels in the testis, LH levels in the pituitary, the capacity of the testis to respond to gonadotropin stimulation, i.e., the production of testosterone in vitro, and by the testicular binding of labeled human chorionic gonadotropin (hCG). Measurement of testosterone and LH levels in rat serum, the testis, or the pituitary showed that both hormones were enhanced throughout the 3-month treatment period. The hypergonadotropism was associated with the increase of interstitial cell response to hCG in vitro for up to 3 months. As with rats, both serum and pituitary LH were increased in mice at 4 weeks but not at 13 weeks. However, in contrast to rats, no significant increase in testosterone was observed in mice either in vivo or ex vivo during the course of the study. This suggests a difference between the rat and mouse in the response of the Leydig cell to the LH stimulation associated with procymidone administration. These differences in the response of interstitial cells to procymidone may be the basis for the distinct species responses to procymidone-induced Leydig cell tumorigenesis. The sustained response of the Leydig cells to stimulation in the rat results in chronic hyperplasia and subsequent benign tumor formation, while the attenuated response of Leydig cells in the mouse is associated with neither hyperplasia nor neoplasia.

Effect of chronic L-dopa administration on serum luteinizing hormone levels in male rats

We examined whether the repeated oral administration with a high dose of L-3-(3,4-dihydroxyphenyl)-alanine (L-DOPA) in 0.5% carboxymethyl cellulose increases serum luteinizing hormone (LH) levels in male rats. Serum LH levels were increased 4 h after a single administration of 1000 mg/kg L-DOPA to male rats, and returned to control levels within 8 h after administration. Four hours after a single administration, serum LH levels were significantly increased by L-DOPA at 1000 mg/kg, but not at 20, 100 or 200 mg/kg. Decreases in body weight and relative weight of the prostate were observed after 7 and 14 days of administration of 1000 mg/kg per day L-DOPA, but no changes were observed in weight of the testis, epididymis or seminal vesicle. The administration of L-DOPA at 500 or 1000 mg/kg per day for 7 or 14 days resulted in increased basal serum LH levels and decreased basal serum prolactin levels 24 h after the last administration. Serum testosterone levels tended to be higher in treated than in control rats. The levels of two metabolites of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), in rats treated with 500 mg/kg per day tended to be slightly higher than those in control rats after 7 days of administration. Levels of DA, DOPAC and HVA were significantly increased after 7 and 14 days of administration of 1000 mg/kg per day and after 14 days of administration of 5000 mg/kg per day. The level of norepinephrine, but not its metabolite 3-methoxy-4-hydroxyphenylglycol, was significantly increased after only 7 days of administration of 1000 mg/kg per day. No significant changes were observed in levels of 5-hydroxytryptamine or its metabolite 5-hydroxyindole-3-acetic acid with administration of 500 or 1000 mg/kg per day. These findings suggest that a prolonged treatment with a high dose of L-DOPA in male rats induces release of LH from the pituitary, resulting in sustained elevation of LH levels in peripheral circulation.