Influence of feeding schedule on chronopharmacological aspects of gentamicin in mice

The effects of the time of day of drug administration on the subchronic toxicity and pharmacokinetics of gentamicin, as well as the role of feeding schedule on circadian rhythms, were investigated in mice. ICR male mice were housed in a light-dark (LD) cycle (12:12) with food and water ad libitum (ALF) or under a time-restricted feeding (TRF) schedule (feeding time: 8 h during the light phase) for 1 day or 14 days before drug administration. The animals were given a single subcutaneous dose of gentamicin 180 mg/kg for the kinetic studies and subcutaneous doses of gentamicin 180 mg/kg/day for 14 days or 220 mg/kg/day for 18 days for the subchronic toxicity studies. A significant dosing-time dependency was shown for mortality and body weight loss, with higher values at midlight and lower ones at the middark (p < 0.05). A significant circadian rhythm was also found for gentamicin kinetics in ALF mice, with the highest clearance at middark and the lowest one at midlight (p < 0.01). The kinetic rhythm of gentamicin coincided well with the toxicity rhythm of the drug. The TRF schedule had a marked influence on the rhythms of gentamicin kinetics and toxicity, showing lowest clearance and higher toxicity at middark. The rhythm of subchronic toxicity of gentamicin seems to be due, at least in part, to the rhythm in kinetics and is strongly influenced by the feeding schedule. Thus, the timing of dosing is an important factor in the kinetics and the subchronic toxicity of gentamicin administration in mice, and the manipulation of feeding schedule can modify the rhythm of the toxicity by changing the rhythm of gentamicin kinetics.

Purification and characterization of prolyl endopeptidase from rat skin

An enzyme with the specificity of a prolyl endopeptidase was purified approximately 329-fold from rat skin. The enzyme has a molecular weight of 70,000 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a pH optimum of 5.8 as checked with 7-(Succinyl-Gly-Pro)-4- methylcoumarinamide (Suc-Gly-Pro-MCA) as the substrate. The optimal temperature for the enzyme activity was 40 degrees C. The Km and Vmax values for Suc-Gly-Pro-MCA were 0.7 mM and 68 nmol/min per mg protein, respectively. The enzyme activity was markedly inhibited by diisopropyl fluorophosphate, p-chloromercuribenzoic acid, N-ethylmaleimide, Zn2+ and Cu2+, while it was partially inhibited by phenylmethanesulphonyl fluoride. The purified enzyme was shown to release the N-terminal tetrapeptide, Arg-Pro-Lys-Pro, from substance P producing the C-terminal heptapeptide, Gln-Gln-Phe-Phe-Gly-Met- CONH2. In the skin, this enzyme might be related to the inactivation of substance P.

[Reconstruction of the pulmonary outflow tract without prosthetic conduit for correction of tetralogy of Fallot with pulmonary atresia]

We reconstructed right ventricular outflow tract without prosthetic conduit for 2 year 11 month and 59 day old Tetralogy of Fallot with pulmonary atresia patients. Left appendage anastomosed between pulmonary trunk and right ventricle was utilized as the posterior wall of the tract. Pericardial patch covered the tract the beneficial methods for patients with Tetralogy of Fallot with pulmonary atresia to avoid late postoperative deleterious complications of prosthetic conduit.

[Anatomic correction without extracardiac conduit for Taussig-Bing malformation (REV procedure)]

A 2-year-old boy with Taussig-Bing malformation with mild pulmonary stenosis underwent anatomical repair without extracardiac conduit (REV procedure). He had pulmonary arterial banding at 4 months of age, and REV procedure was performed at 2 years and 4 months of age. Under cardiopulmonary bypass, enlargement of ventricular septal defect were performed with an internal conduit. Pulmonary arterial trunk was divided and the proximal end was closed. Direct anastomosis of the posterior wall of the distal pulmonary arterial trunk to the right ventriculotomy was carried out without transection of aorta or translocation of pulmonary artery. Right ventricular outflow tract (RVOT) was reconstructed with a patch bearing a monocusp. The postoperative course was very smooth and postoperative cardiac catheterization revealed no stenosis in both left and right ventricular outlfow tract and good cardiac performance.

Fate of right ventricular hypertrophy in tetralogy of Fallot after corrective surgery

To elucidate the reversibility of right ventricular (RV) myocardial hypertrophy in tetralogy of Fallot (TF), 30 patients underwent RV endomyocardial biopsies 1 to 25 years (mean 9.7 +/- 6.6) after corrective surgery. Myocardial cell diameter was evaluated by comparing histopathologic data with preoperative patients with TF and normal subjects. As a whole, postoperative cell diameter was smaller than that of age-matched preoperative patients with TF, and larger than that of age-matched normal subjects. In 7 patients without significant residual pulmonary stenosis whose preoperative data were also available, cell diameter significantly decreased after surgery (17.1 +/- 2.1 to 14.0 +/- 2.1 microns, p < 0.01). There was a positive correlation between postoperative cell diameter and age at study (p < 0.01). To negate the influence of age, cell diameter was expressed in terms of a percentage of age-matched normal values (percent cell diameter). There was no significant correlation between percent cell diameter and age at surgery, age at study or the follow-up periods. There were positive correlations between percent cell diameter and the following parameters: RV systolic pressure (p < 0.05), percent normal RV end-diastolic (p < 0.05) and end-systolic (p < 0.01) volumes. These results demonstrate that RV myocardial hypertrophy in TF can regress to some extent after corrective surgery if significant residual pulmonary stenosis is avoided.

Predictable factors for estimating prognosis of patients after resection of hepatocellular carcinoma

BACKGROUND

Although many studies have been concerned with a clarification of the relation between various clinicopathologic factors and the prognosis of operated hepatocellular carcinoma (HCC), few studies have focused on the prognostic predictability of mitotic index and anti-hepatitis C virus (anti-HCV).

METHODS

One hundred forty cases of HCC with hepatic resection were observed from 1 to 11 years, and the relationship among various clinicopathologic factors, including the mitotic index and anti-HCV, and prognosis was evaluated.

RESULTS

Age at the time of operation, positive results for hepatitis B surface antigen or anti-HCV, accompanying cirrhosis, and the degree of tumor necrosis due to transarterial embolization did not influence the prognosis significantly. Patients with hepatitis C virus-related cases had a better prognosis than patients with hepatitis B-related cases. Patients with a single and small carcinoma smaller than 2 cm had a significantly better prognosis than those who had larger and/or multiple tumors. A better prognosis also was observed in the carcinomas with no histologic invasion into portal vein branches, low Edmondson grades, and low mitotic activities when compared with the counterpart of each group. Among these factors, the mitotic index was correlated best with prognosis in the current study.

CONCLUSIONS

The examination of mitotic index was quite simple, and the index was a helpful factor in predicting prognosis.

Predictable factors for estimating prognosis of patients after resection of hepatocellular carcinoma

BACKGROUND

Although many studies have been concerned with a clarification of the relation between various clinicopathologic factors and the prognosis of operated hepatocellular carcinoma (HCC), few studies have focused on the prognostic predictability of mitotic index and anti-hepatitis C virus (anti-HCV).

METHODS

One hundred forty cases of HCC with hepatic resection were observed from 1 to 11 years, and the relationship among various clinicopathologic factors, including the mitotic index and anti-HCV, and prognosis was evaluated.

RESULTS

Age at the time of operation, positive results for hepatitis B surface antigen or anti-HCV, accompanying cirrhosis, and the degree of tumor necrosis due to transarterial embolization did not influence the prognosis significantly. Patients with hepatitis C virus-related cases had a better prognosis than patients with hepatitis B-related cases. Patients with a single and small carcinoma smaller than 2 cm had a significantly better prognosis than those who had larger and/or multiple tumors. A better prognosis also was observed in the carcinomas with no histologic invasion into portal vein branches, low Edmondson grades, and low mitotic activities when compared with the counterpart of each group. Among these factors, the mitotic index was correlated best with prognosis in the current study.

CONCLUSIONS

The examination of mitotic index was quite simple, and the index was a helpful factor in predicting prognosis.

Long-term appraisal of coronary bypass operations in familial hypercholesterolemia

Long-term results of coronary artery bypass grafting (CABG) in consecutive 32 patients with familial hypercholesterolemia, 6 homozygotes and 26 heterozygotes between 1976 and 1990, were analyzed. Seventeen patients in the early series underwent CABG with vein grafts alone. Subsequently, 15 patients underwent CABG with internal mammary artery grafting to the left anterior descending artery and received intensive lipid-lowering treatments early after CABG. All homozygotes and 1 heterozygote received intermittent low-density lipoprotein apheresis after CABG. There was only one late noncardiac death (3%), and the actuarial rates of freedom from cardiac events (myocardial infarction, cardiac death, and angina pectoris) were 60% at 5 and 10 years for homozygotes, and 87% and 73% for heterozygotes. The cardiac event-free curve for the heterozygous familial hypercholesterolemia group was comparable with that for the random age-matched subset of patients without familial hypercholesterolemia who underwent CABG during the same period. Two of 3 homozygotes and 4 of 14 heterozygotes in the early series had one or more cardiac events, whereas no patients in the late period had cardiac events. The patency rate of internal mammary artery grafts to the left anterior descending artery from 1 to 3 years after CABG was significantly higher than that of vein grafts to the left anterior descending artery (92 versus 45%; p < 0.05). Abdominal aortic aneurysm developed postoperatively in 2 homozygotes and 2 heterozygotes without sufficient cholesterol reduction. In conclusion, internal mammary artery grafting in combination with postoperative intensive lipid-lowering treatments, including low-density lipoprotein apheresis, may provide acceptably good long-term results of coronary revascularization in patients with FH.

Influence of circadian-stage-dependent dosing schedule on nephrotoxicity and pharmacokinetics of isepamicin in rats

Nephrotoxicity was more marked in rats receiving isepamicin at midlight than at middark. And, the once-daily administration at middark induced a lesser degree of nephrotoxicity than the twice-daily injection, which indicates that the once-daily treatment therapy may have potential value in the clinical use of aminoglycosides.

[Clinical study of continuous local arterial-infusion chemotherapy for severely advanced hepatocellular carcinoma (HCC) using reservoir]

We attempted continuous local arterial-infusion chemotherapy using reservoir for patients with severely advanced hepatocellular carcinoma (HCC), with no indications for operation, PEIT or TAE because of the advanced clinical stage, Vp-factor, and so on. Twenty-two HCC patients were given continuous arterial-infusion of 5-FU + CDDP and were observed for 36-443 days from June, 1991 to December, 1992. Until the end of 1992, we had 3 partial response (PR) cases and 3 progressive disease (PD) cases, and the other cases showed no change (NC). Except for a case in which therapy was stopped because of renal failure, no patients were disturbed by side effects, and 68.2% of the patients completed all of their therapy as outpatients. Because CDDP can amplify the effect of 5-FU in addition to its own effect as a biochemical modulator, and because continuous infusion can strengthen the effect of 5-FU and reduce the side effects of CDDP, we consider continuous local arterial-infusion of 5-FU and CDDP to be an effective therapy for severely advanced HCC. This treatment does not cure the carcinoma but helps to slow its progress and assure good QOL.

Successful mitral valve replacement for MELAS

Successful mitral valve replacement for severe mitral regurgitation in a patient with mitochondrial encephalomyopathy is reported. Renal failure due to low cardiac output improved dramatically after mitral valve replacement and he was discharged 10 weeks after surgery. The surgical indication and timing for valvular dysfunction in patients with mitochondrial cardiomyopathy are discussed.

[Survey for primary tumor site in patients with initial clinical presentation of bone metastasis]

Among the patients who were examined with bone scintigraphy between April 1985 and March 1991, there were 27 patients whose initial clinical manifestation was bone metastasis and who were surveyed for the primary tumor site. The primary tumor site could be identified in 20 patients (74%), consisting of 9 patients with lung cancer, 3 with prostate cancer, 3 with hepatoma, 2 with renal cancer, and one each with thyroid cancer, adrenal cancer, and pleural malignant mesothelioma. In 17 of the 20 patients, the primary site had been detected within two months after presentation. Examinations which were helpful in identifying the primary site included chest radiography, sputum cytology, abdominal sonography, serum prostatic acid phosphatase level and pathologic examination of biopsy specimens. 99mTc-PMT scintigraphy was useful in the diagnosis of the hepatoma when accumulation was observed at the metastatic sites. In 2 patients, lung cancer had been recognized using follow-up chest radiography 3 and 6 months after presentation, respectively. One patient was diagnosed at autopsy as having adrenal cancer. In 7 patients the primary site remains unknown. Histology examination of the biopsy specimen performed in 6 of these patients revealed 4 to be adenocarcinoma and 2 undifferentiated carcinoma. The average survival period of the 17 patients who died was 9.5 months. Four patients are alive, and the outcome in the remaining 6 could not be determined.

Predictable factors for estimating prognosis of patients after resection of hepatocellular carcinoma

BACKGROUND

Although many studies have been concerned with a clarification of the relation between various clinicopathologic factors and the prognosis of operated hepatocellular carcinoma (HCC), few studies have focused on the prognostic predictability of mitotic index and anti-hepatitis C virus (anti-HCV).

METHODS

One hundred forty cases of HCC with hepatic resection were observed from 1 to 11 years, and the relationship among various clinicopathologic factors, including the mitotic index and anti-HCV, and prognosis was evaluated.

RESULTS

Age at the time of operation, positive results for hepatitis B surface antigen or anti-HCV, accompanying cirrhosis, and the degree of tumor necrosis due to transarterial embolization did not influence the prognosis significantly. Patients with hepatitis C virus-related cases had a better prognosis than patients with hepatitis B-related cases. Patients with a single and small carcinoma smaller than 2 cm had a significantly better prognosis than those who had larger and/or multiple tumors. A better prognosis also was observed in the carcinomas with no histologic invasion into portal vein branches, low Edmondson grades, and low mitotic activities when compared with the counterpart of each group. Among these factors, the mitotic index was correlated best with prognosis in the current study.

CONCLUSIONS

The examination of mitotic index was quite simple, and the index was a helpful factor in predicting prognosis.

[The study of continuous local arterial-infusion chemotherapy with 5-FU + CDDP for patients with severely advanced HCC--for the elongation of the life-span and the improvement of QOL]

We tried continuous local arterial-infusion chemotherapy using 5-FU + CDDP with an implanted reservoir, for patients with severely advanced hepatocellular carcinoma (HCC), who had no indications for operation, PEIT or TAE. Arterial-infusion was continued for one week, followed by a one-week no-infusion period, and this treatment was repeated 1-32 times, and patients were observed for 36-549 days. Until the end of April 1993, the one-year survival rate was 61.1%. There were 3 partial remission (PR) cases, 3 progressive disease (PD) cases and the other cases showed no change (NC). Only one patient had any side effects, and all could continue as outpatients for 94.0% of the entire therapy. The patients' evaluation of QOL revealed no differences of QOL according to the length of the whole therapy, the history of rehospitalization during therapy, response to therapy, etc. But PR cases tended to show improved QOL. Therefore we considered this as effective therapy for the elongation of the life-span and the improvement of QOL.

Circadian variation in amikacin clearance and its effects on efficacy and toxicity in mice with and without immunosuppression

A once-daily dosage regimen has been recently recommended in the use of aminoglycoside antibiotics since they induce a postantibiotic effect. In choosing this regimen, one must determine the most appropriate time of day for administration of the drug. We investigated the effects of the timing of amikacin (AMK) administration on the kinetics, the efficacy against intraperitoneal infection with Pseudomonas aeruginosa, and the toxicity of AMK in mice with and without immunosuppression. We found circadian variations in the kinetics, efficacy, and toxicity of the drug in mice. Male and female ICR mice, which were housed under a light-dark (12:12 h) cycle with free food and water intake, were injected subcutaneously with AMK sulfate 50 mg/kg body wt. There was a circadian variation in AMK clearance for both sexes with the maximum value in the dark phase and the minimum in the light phase after a single administration. When AMK 500 mg/kg/day was repeatedly administered once daily for 30 days, higher toxicity was demonstrated in mice injected with the drug at the time of day with lower AMK clearance, although no difference was demonstrated in the toxicity between the two time points with different AMK clearance when AMK 1,500 mg/kg was administered in a single dose. The ED50 of AMK to cure the infected mice in the midlight phase (13:00 h) with lower clearance was significantly lower than that in the middark phase (01:00 h) with higher clearance. In contrast, the ED50 in the early light phase (09:00 h) was significantly lower than that in the early dark phase (21:00 h), although AMK clearance was no different between these two different time points. In mice premedicated with cyclophosphamide to suppress immune functions, the difference in the ED50 of AMK was still demonstrated between 13:00 and 01:00 h, but not between 09:00 and 21:00 h. The present study shows not only that there were circadian variations in both AMK clearance and toxicity after repeated administration, but also that there was a circadian variation in the efficacy of AMK in mice infected with P. aeruginosa. These results suggest that the timing of drug administration should be considered in pharmacotherapy with AMK and that the most appropriate time of administration in mice and nocturnal animals may be in the midlight (resting) phase. They also suggest that the ED50 of AMK against P. aeruginosa infection may be influenced not only by the circadian variation in pharmacokinetics but also by the variations in immune systems suppressed by cyclophosphamide.

Chronotoxicity and chronopharmacokinetics of methotrexate in mice: modification by feeding schedule

The circadian rhythms of the toxicity and the pharmacokinetics of methotrexate (MTX), as well as the effects of manipulation of feeding schedule on the rhythms, were investigated in mice. Male ICR mice were housed under a standardized light-dark cycle (12:12) with food and water ad libitum (ALF) or under the time-restricted feeding (TRF) schedule (8 hr during the light phase) for 1 day or 14 days before the drug administration. The animals received MTX (100 mg/kg, i.p.) once daily for 7 days in the toxicity studies and a single dose of MTX (100 mg/kg, i.p.) for the kinetic studies. Under the ALF, a significant dosing time dependency was demonstrated for the toxicity of MTX with a longer survival time for the middark dosing and a shorter one for the midlight dosing. The MTX kinetics also showed a significant rhythm, with the highest clearance at middark and the lowest one at midlight. The rhythm in MTX kinetics well coincided with that in the toxicity of the drug. The TRF had a marked influence on the rhythms of MTX kinetics and toxicity. Thus, the timing of dosing is important in the kinetics and the toxicity of MTX in mice, and the manipulation of feeding schedule can modify the rhythm of the toxicity by changing that of the MTX kinetics.

Multiple neutralizing B-cell epitopes of human T-cell leukemia virus type 1 (HTLV-1) identified by human monoclonal antibodies. A basis for the design of an HTLV-1 peptide vaccine

We have generated 153 human mAb reacting with natural envelope glycoprotein-gp46 of human T-cell leukemia virus type-1 (HTLV-1) by the EBV-transformation of B lymphocytes obtained from patients with HTLV-1-associated myelopathy (HAM)/Tropical spastic paraparesis (TSP). Twenty-four of these mAb had neutralizing activity of HTLV-1 as determined by an HTLV-1-induced syncytium formation inhibition assay in vitro. The reactivity of these neutralizing mAb was studied by using 9 different synthetic peptides covering immunodominant regions of the gp46. Thirteen out of these 24 neutralizing mAb reacted with gp46 peptide 175-199, whereas one mAb reacted with gp46 213-236 and another one with gp46 288-317. The other 9 neutralizing mAb did not react with any of these peptides. Fine epitope mapping of the mAb reacting with gp46 peptide 175-199 revealed the presence of 4 distinct neutralizing B-cell epitopes on this region; (1)187-193, (2)191-196, (3)193-199, and (4) continuous conformational B-cell epitope. The competitive antibody-binding inhibition experiments by soluble phase synthetic peptides showed that the binding activity of these neutralizing mAb to the corresponding synthetic peptides is equal to or a little lower than that to native gp46 protein, suggesting that synthetic peptides can form structure very similar to the neutralizing epitopes on native gp46 protein. The present study is the first systematic demonstration of multiple neutralizing B-cell epitopes of HTLV-1 in human HTLV-1 infection. It would be possible to prepare a synthetic peptide vaccine against HTLV-1 based on these newly identified multiple linear neutralizing B-cell epitopes of HTLV-1.

Multiple neutralizing B-cell epitopes of human T-cell leukemia virus type 1 (HTLV-1) identified by human monoclonal antibodies. A basis for the design of an HTLV-1 peptide vaccine

We have generated 153 human mAb reacting with natural envelope glycoprotein-gp46 of human T-cell leukemia virus type-1 (HTLV-1) by the EBV-transformation of B lymphocytes obtained from patients with HTLV-1-associated myelopathy (HAM)/Tropical spastic paraparesis (TSP). Twenty-four of these mAb had neutralizing activity of HTLV-1 as determined by an HTLV-1-induced syncytium formation inhibition assay in vitro. The reactivity of these neutralizing mAb was studied by using 9 different synthetic peptides covering immunodominant regions of the gp46. Thirteen out of these 24 neutralizing mAb reacted with gp46 peptide 175-199, whereas one mAb reacted with gp46 213-236 and another one with gp46 288-317. The other 9 neutralizing mAb did not react with any of these peptides. Fine epitope mapping of the mAb reacting with gp46 peptide 175-199 revealed the presence of 4 distinct neutralizing B-cell epitopes on this region; (1)187-193, (2)191-196, (3)193-199, and (4) continuous conformational B-cell epitope. The competitive antibody-binding inhibition experiments by soluble phase synthetic peptides showed that the binding activity of these neutralizing mAb to the corresponding synthetic peptides is equal to or a little lower than that to native gp46 protein, suggesting that synthetic peptides can form structure very similar to the neutralizing epitopes on native gp46 protein. The present study is the first systematic demonstration of multiple neutralizing B-cell epitopes of HTLV-1 in human HTLV-1 infection. It would be possible to prepare a synthetic peptide vaccine against HTLV-1 based on these newly identified multiple linear neutralizing B-cell epitopes of HTLV-1.

Sudomotor potential evoked by magnetic stimulation of the neck

We studied the sudomotor potential in the palm of the hand, evoked by magnetic stimulation of the neck, in 15 normal subjects and five patients with dysautonomia. The potentials consisted of two positive peaks (S1, S2), with mean (+/- SD) onset latencies of 408.5 +/- 31.8 and 619 +/- 61.4 msec. The sudomotor potential was clearly obtained only from the palm and was influenced by stimulus intensity, coil position, current direction in the coil, atropine or pilocarpine iontophoresis, and motor effort. With this method, we estimated the postganglionic sympathetic conduction time and the central reflex time, the mean values (+/- SD) of which were 408.5 +/- 31.8 and 323.3 +/- 45.2 msec. In three patients with severe dry skin, the sudomotor potential and the sympathetic skin response were not obtained. A patient with OPCA had a prolonged central reflex time, and a patient with alcoholic polyneuropathy showed a delayed sudomotor potential. Sudomotor potential is a noninvasive and useful method for evaluating sympathetic sudomotor function in patients with central and peripheral nervous system disorders.

[Acute biliary pancreatitis]

Pathogenesis, diagnosis, predicting severity, and treatment of acute biliary pancreatitis are reviewed. Clinical characteristics, treatment and outcome were investigated in 23 patients with severe, acute biliary pancreatitis. Conservative treatment is successful in most of patients with acute biliary pancreatitis. Surgical treatment for biliary stones should be followed by an initial conservative treatment. However, in patients with severe pancreatitis, who has poor prognosis, intensive care is necessary and surgical treatment must be adequately performed, in failure of active medical treatments. In these cases, the timing of operation is important. When biliary lesions, acute septic cholangitis or impacted ampullary stones, are responsible for the severe condition, and can't be treated by a medical procedure, such as PTCD or EST, surgical treatment of the biliary tract should be considered.

[Sutureless aortic valve replacement for peri-annular pseudoaneurysm and perivalvular leakage due to prosthetic valve endocarditis]

A 49-year-old man who had undergone AVR entered our hospital with congestive heart failure and continuing slight fever. By cardiac imaging, he was diagnosed prosthetic valve endocarditis with periannular pseudoaneurysm and perivalvular leakage. He underwent a new translocation method using a composite valve (a prosthetic valve directly sutured a ring prosthesis, which was separated from an intraluminal ringed graft). Post operative course was uneventful. He recovered well after the operation.

[Aldosterone response to various stimuli in hyperthyroidism: in vivo and in vitro studies]

Responses of plasma aldosterone (PA) to alpha-ACTH-(1-24) (250 micrograms, im) injection and graded angiotensin II (AII) infusions (2, 4 and 8ng/kg/min for 30 min at each dose) on a constant sodium intake (170mEq daily) were assessed in 17 patients with Basedow's disease and 13 age-matched normal subjects. Aldosterone production in response to ACTH, AII and potassium in adrenal zona glomerulosa cells from L-thyroxine-induced hyperthyroid rats (H-rats) were also examined. Basal levels of plasma renin activity (PRA) and urinary aldosterone excretion were significantly higher (p < 0.01 and p < 0.05, respectively) in the patients with Basedow's disease than in the normal subjects, whereas basal PA level was similar in the two groups. The ACTH injection induced similar increases in plasma cortisol, plasma 18-hydroxycorticosterone (18-OHB) and PA in the two groups. The graded AII infusions also produced increases in plasma 18-OHB and PA in the two groups. Responses of these two corticosteroids to AII were, however, significantly lower (p < 0.05) in the patients with Basedow's disease than in the normal subjects. In the experimental animal study, basal PRA levels and the adrenal glomerulosa cell count/adrenal were significantly higher (p < 0.05) in the H-rats than in the control rats, whereas basal PA levels were similar in the two groups. Aldosterone production in response to AII, ACTH, and potassium increased in a dose-dependent manner in the two groups. Responses of aldosterone production to AII were, however, significantly lower (p < 0.05) in the H-rats than in the control rats. These results suggest that the impaired responsiveness of adrenal zona glomerulosa cells to AII, as well as an increased metabolic clearance rate of aldosterone, may be involved in the abnormal aldosterone metabolism in hyperthyroidism.