• Korean Journal of Biological Psychiatry
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• v.7 no.1
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• pp.85-98
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• 2000

Objective : There are four possible explanations for the sexual dysfunction of schizophrenics. The first is the possibility of a real structural aspect. The second possibility is that sexual function changes secondary to the illness. The third possibility is that there are medical and sociocultural barriers to sexual expression for chronic schizophrenics. The fourth possibility is that sexual dysfunction due to antipsychotic medication. However, we didn't know the precise cause of sexual dysfunction in schizophrenics. Therefore, the purpose of this study was to explore the mechanism of illness itself and antipsychotics on sexual dysfunction in male schizophrenics. Methods : The serum prolactin(PRL), testosterone(TST), and the plasma serotonin(5-HT) concentrations were measured by radioimmunoassay and high performance liquid chromatography method for 100 healthy male schizophrenics according to the DSM-IV. Concomitantly, the severity of psychotic symptoms using Clinical Global Impression(CGI), Brief Psychiatric Rating Scale(BPRS), Positive and Negative Syndrome Scale(PANSS), and the severity of side effects for antipsychotics using Extrapyramidal Side Effects Scale(EPSE), Anticholinergic Side Effects Scale(ACSE), the cognitive function using PANSS-Cognitive Function(PANSS-CF), Mini Mental State Exam-Korean(MMSE-K), and the sexual dysfunction using Sexual Functioning Questionnaire(SFQ), Questionnaire for Sexual Dysfunction in Men were assessed. The PRL, TST, and 5-HT levels of 50 healthy male controls who had no medical, neurological, and psychiatric illnesses were evaluated. The sexual function using SFQ(items FGa, FNa) were also assessed. Furthermore, the correlation with age, education, religion, economic status, age at onset, duration of illnesses, duration of admission, levels of PRL, TST, 5-HT, antipsychotic dosages, potency, benztropine, total duration of medication, EPSE, ACSE, CGI, BPRS, PANSS, PANSS-CF, MMSE-K and sexual dysfunctions were identified in male schizophrenics. Results : 1) The frequencies of sexual dysfunctions for schizophrenics(80%) were significantly(p<0.001) higher than those for controls(42%). The sexual dysfunctions according to sexual response cycle were 'low sexual desire' 76%, 'impairment of achieving erection' 75%, 'impairment of maintaining erection' 75%, 'impairment of obtaining orgasm' 32%, 'impairment in the quality of orgasm' 61%, 'impairment in quantity of ejaculate' 44%, 'premature ejaculation' 15%, and 'delayed ejaculation' 50%. 2) The PRL, 5-HT levels of schizophrenics($28.5{\pm}20.6ng/ml$, $298.5{\pm}89.1ng/ml$) were significantly(p<0.001) higher than those of controls($10{\pm}5.6ng/ml$, $169.2{\pm}37.8ng/ml$), while the TST levels of schizophrenics($4.3{\pm}1.5ng/ml$) and controls($4.5{\pm}1.2ng/ml$) were not significantly different. The sexual dysfunctions of schizophrenics who had abnormal 5-HT levels($4.7{\pm}1.3$ scores) were significantly(p<0.05) higher than those of who had normal 5-HT levels($3.8{\pm}1.6$ scores) on item D7. 3) The sexual dysfunctions of unmarried schizophrenics were significantly(p<0.01 : p<0.05) higher than those of married schizophrenics($6.1{\pm}2.8$ scores, $4.7{\pm}1.3$ scores on item FGa : ${\beta}$=-0.211 on item FNa). The sexual dysfunctions were positively correlated with the rise of 5-HT levels(r=0.209, p<0.05 on item D4 and r=0.241, p<0.05 on item D7), the higher age at onset(r=0.275, p<0.01 on item FNa : r=-0.202, p<0.05 on item FDa), the longer duration of illnesses(r=0.237, p<0.05 on item D6), the longer duration of admission(r=0.234, p<0.05 on item D4 : r=0.328, p<0.05 on item D6), the longer total duration of medication(r=0.237, p<0.05 on item D6). However, age, education, religion, economic status, PRL, TST levels, antipsychotics dosage, potency, benztropine, ACSE, CGI, BPRS, PANSS, PANSS-CF, MMSE-K scores were not correlated with increased sexual dysfunctions. Conclusions : Male schizophrenics have significantly more sexual dysfunction to compare with controls. The higher frequencies of sexual dysfunctions were low sexual desire and erectile disorder. The unmarried, higher age at onset, and longer duration of diseases were positively correlated with increased sexual dysfunctions. Also high 5-HT levels were positively correlated with increased sexual dysfunctions. This means that studies of plasma 5-HT levels, albeit questionable indicators of central 5-HT function, offer some additional support for the association of sexual dysfunction with excess 5-HT activity as primary pathology of schizophrenia. Our findings suggest that excess 5-HT activity seems to affect the patient's sexual function.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.5
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• pp.615-623
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• 2001

A study of mammary function in relation to glucose metabolism of first lactation Bali cows on grass-legume diets was carried out using 12 primiparous cows (initial BW $263.79{\pm}21.66kg$) for 16 weeks starting immediately post calving. The animals were randomly allocated into 4 dietary treatment groups R1, R2, R3 and R4, receiving from the last 2 months of pregnancy onwards, rations based on a mixture of locally available grass and legume feed ad libitum. On a DM basis R1 contained 70% elephant grass (PP, Penicetum purpureum) plus 30% Gliricidia sepia leaves (GS), R2 was 30% PP plus 25% GS supplemented with 55% Hibiscus tilliacius leaves (HT, defaunating effect), R3 and R4 were 22.5% PP+41.25% GS+11.25% HT+25% concentrate, with R4 supplemented with zinc-diacetate. TDN, CP and zinc contents of the diets were 58.2%, 12.05% and 18.3 mg/kg respectively for R1, 65.05%, 16.9% and 25.6 mg/kg respectively for R2, 66.03%, 16.71% and 29.02 mg/kg respectively for R3 and 66.03%, 16.71% and 60.47 mg/kg respectively for R4. Milk production and body weights were monitored, an energy and protein balance trial conducted, overall glucose kinetics parameters assessed, mammary blood flow (MBF) and metabolite arteriovenous differences (${\Delta}AVs$) measured to get uptake data and mammary performance relationships. Parameters of glucose kinetics at peak lactation or during dry condition were not affected by ration quality. Glucose pool size, space of distribution and flux increased by 61.77, 62.26 and 82.08%, respectively, during lactation compared to the dry period. Mean glucose flux of lactating Bali cows was $5.52mg/min.kgBW^{0.807}$ which resembles the range of values of temperate dairy cows. Calculation showed that glucose requirements for maintenance, milk lactose and fat-glycerol synthesis, and the formation of NADPH reached 461.69 g for a yield of 1 kg/d or equal to 320.62 mg/min, which was less than the average glucose flux of lactating Bali cows of 481.35 mg/min. Mammary blood flow (MBF) values ranged from 56 to 83 l/h for the different treatments and the ratio MBF per kg milk produced improved from av. 1540 l/kg for R1 to av. 967 l/kg for R4 treated cows. Mammary glucose uptake ranged from 6.27 to 12.03 g/h or 120 to 140 g/kg milk. Glucose uptake was mass-wise 2 to 4 times the amount secreted as lactose, which indicated values less than the calculated mammary glucose needs and that little lactose was synthesized. The excess glucose taken-up was used for other metabolic processes. Linear relationships between metabolite ${\Delta}AVs$ and arterial blood plasma concentration [A] showed that in Bali cows triglycerides (TG), phenylalanine (Phe) and tyrosine (Tyr) have high coefficients of determination, i.e. 0.77, 0.81 and 0.69, respectively. For glucose, the relationship is quadratic with an $R^2$ value of 0.49. It was concluded that lactose synthesis was inadequate, which led to a speculation that milk yield could be improved by increased lactose synthesis.

• The Korean Journal of Pharmacology
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• v.18 no.1
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• pp.43-54
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• 1982

Bile formation is a complex process comprised of three separate physiologic mechanism operating at two anatomical sites. At present time, it was known that at least two processes are responsible for total canalicular secretion at the bile canaliculus. One of the processes is bile salt-dependent secretion (BSDS) hypothesis that the active transport of bile salts from plasma to bile provided a primary stimulus for bile formation: the osmotic effect of actively transported bile acid was responsible for the movement of water and ions into bile. The other process is bile salt-independent secretion (ESIS), which is unrelated to bile salt secretion at the canaliculus and which may involve the active transport of sodium. The third process for bile formation involves the biliary ductal epithelium. Secretin-stimulated bile characteristically contained bicarbonate in high concentration. Therefor, it was suggested that secretin stimulated water and bicarbonate secretion from the biliary ductules. One the other hand, it was found that a large amounts of cAMP was present in canine bile but no apparent relationship between bile salt secretion and cAMP content in dog bile. However, bile flow studies in human have demonstrated that secretin and glucagon increase bile cAMP secretion as does secretin in baboons. Secretin increases baboon bile duct mucosal cAMP levels in addition to bile CAMP levels suggesting that in that species secretin-stimulated bile flow may be cAMP mediated. It has been postulated that glucagon and theophylline which increase the bile salt-independent secretion in dogs might act through an increased in liver cAMP content. In a few studies, the possible role of cAMP on bile formation has teen tested by administration of an exogenous derivative of cAMP, dibutyryl cAMP. In the rat, DB cAMP did not modify bile flow, but injection of DB cAMP in the dog promoted an increase in the bile salt-independent secretion. Because of these contradictory results, this study was carried out to examine the relationship between cyclic nucleotides and bile flow due to various bile salts as well as secretin or theophylline. Experiments were performed in rabbits with anesthesia produced by the injection of seconal(30 mg/kg). Rabbits had the cystic duct ligated and the proximal end of the divided common duct cannulated with an appropriately sized polyethylene catheter. A similar catheter was placed into the inferior vena cava for administration of drugs. Bile was collected for determination of cyclic nucleotides and total cholate in 15 min. intervals for a few hours. The results are summerized as followings. 1) Administrations of taurocholic acid or chenodeoxycholic acid increased significantly the concentrations of cAMP and cGMP in bile of rabbits. 2) Concentration of cAMP in bile during the continuous infusion of ursodeoxycholic acid, was remarkedly increased in accordance with the increase of bile flow, while on the contrary concentration of cGMP in bile was decreased significantly. 3) Dehydrocholic acid and deoxycholic acid significantly increased bile flow, total cholate output and cyclic nucleotides in bile. 4) Only cAMP concentration in bile was significantly increased from control value by secretin, while theophylline increased cAMP as well as cGMP in rabbit bile. 5) In addition, the administration of secretin to taurocholic acid-stimulated bile flow increased cAMP while theophylline produced the increases of cAMP and cGMP in bile. 6) The administration of insulin to taurocholic acid-stimulated bile flow decreased cAMP concentration, while on the contrary cGMP was remarkedly increased in rabbit bile.

• The Korean Journal of Physiology
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• v.24 no.1
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• pp.27-37
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• 1990

The extrafetal transfer of $Li^{+}$ in amniotic fluid was studied in 45 pregnant rabbits. LiCl solution was administered either intravenously to mother or directly into the amniotic sac and monitored the appearance and disappearance of $Li^{+}$ in the amniotic fluid, then calculated the transfer rate of $Li^{+}$ of extrafetal origin. To study the transplacental $Li^{+}$ transfer, a solution of 150 mM LiCl was infused continuously via maternal vein (initial dose: 0.7 mmol/kg, maintaining dose: 0.03 mmol/kg/min) and the $Li^{+}$ concentration was measured in maternal blood and amniotic fluid after 60 and 120 minutes of infusion. Change in the volume of aminotic fluid was determined by Congo red dilution method at the same time. Effects of duration of gestation was not considered in this study. Extrafetal transport of $Li^{+}$ into the amniotic fluid was estimated by comparing the $Li^{+}$ concentration and volume of amniotic fluid determined before and after ligating the placental vessels. Extrafetal $Li^{+}$ transport from the amniotic fluid was determined by observing the time dependent disappearance of $Li^{+}$ and Congo red in amniotic fluid after injecting 0.5 ml solution of 15 mM or 90 mM LiCl and 50 mg/ml Congo red. Following are the results obtained: 1) During infusion of LiCl through maternal vein the ratio of the aminotic $Li^{+}$/maternal plasma $Li^{+}$ increased significantly along with the increment of fetal weight. 2) The volume of amniotic fluid of larger fetuses than 20.5 gm increased significantly during administration of LiCl while that of smaller fetuses did not change. 3) After umbilical cord ligation the $Li^{+}$ concentration of amniotic fluid of larger fetuses than 20.5 gm was decreased to $59.9{\pm}10.3%$ and $56.9{\pm}42.9%$ $(mean{\pm}S.D.)$ of those of control group after 60 and 120 minutes of LiCl infusion respectively. In amniotic fluid of smaller fetuses than 20.5 gm, there was no significant difference between control and ligation groups. 4) The disappearance rate of Congo red in the amniotic fluid was $45.2{\pm}8.2%/hr$. 5) The disappearance rate of $Li^{+}$ after intraamniotic injection of LiCl depended on the amount injected. On injecting $7.5\;{\mu}mol$ LiCl, $Li^{+}$ disappeared rapidly from the amniotic fluid and the rates after 60 min and 90 min were $97.0{\pm}2.8,\;98.5{\pm}2.0%$ respectively. On injecting $45\;{\mu}mol$ LiCl, the rates were $56.0{\pm}15.4,\;78.9{\pm}14.5%$ at 60 and 90 min. 6) From the above results it was concluded: a) $Li^{+}$ transfer into the amniotic fluid increased along with the fetal growth and one half of $Li^{+}$ influx is through the extrafetal route even after the maturation of fetal kidney. b) One half of the $Li^{+}$ transfer from the amniotic fluid was through swallowing of fetus, while the remaining half was transfered rapidly through amniotic membrane, which was concentration limited.

• The Korean Journal of Mycology
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• v.44 no.1
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• pp.23-30
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• 2016

This study was conducted for comparison of ingredients, phytochemical compounds and antioxidant activity of Wofiporia extensa cultured in Gangwon-do, Gyeongsang-do, and Jeolla-do. Three contents of Wofiporia extensa were analyzed as oxygen (46~48%), carbon (38~39%), hydrogen (6.05~6.1%) and nitrogen (0.17~0.21%). The mineral contents of 50% ethanol Wofiporia extensa extracts were measured as sulfur (S) 145~149 ppm, Magnesium (Mg) 69~72 ppm, phosphorus (P) 122~154 ppm and calcium (Ca) 210.61~509.98 ppm. Wofiporia extensa from Gyeongsang-do (509.98 ppm) contained a significantly higher quantity of Ca than that from Gangwon-do (210.62 ppm) and Jeolla-do (223.88 ppm). In the gas chromatograph-mass spectrometry (GC-MS) analysis, oleic acid was identified in three 50% ethanol Wofiporia extensa extracts. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay for antioxidant activity, the $IC_{50}$ values of Wofiporia extensa cultured in Gangwon-do, Gyeongsang-do and Jeolla-do were calculated as 2.966 mg/mL, 23.03 mg/mL, and 4.16 mg/mL and 3.521 mg/mL, 12.17 mg/mL, and 7.40 mg/mL. In the ferric reducing antioxidant power (FRAP) assay, the $IC_{50}$ values of Wofiporia extensa cultured in Gangwon-do, Gyeongsang-do, Jeolla-do were 6.585 mg/mL, 19.06 mg/mL, and 18.97 mg/mL, respectively. In summary, Wofiporia extensa cultured in Gangwon-do had stronger antioxidant activity and higher concentration of oleic acid than that of Geyongsang-do and Jeolla-do. However, Wofiporia extensa cultured in Geyongsang-do contained a much higher concentration of Ca than that of Gangwon-do and Jeolla-do.

• The Korean Journal of Physiology
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• v.16 no.2
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• pp.187-193
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• 1982

The relationship between water and electrolyte metabolism, and dietary intake were studied in 45 healthy Buddhist nuns who were vegetarians aged 20-34, and 28 nursing students aged 20-22 who stayed at the dormitory of Kyungpook Medical School in the Fall, 1981. The Buddhist nuns obtained significantly higher carbohydrate and total caloric intakes but significantly lower protein and lipid intakes than the female students. The Buddhist nuns excreted significantly higher urine output($1,697{\pm}68\;ml/day$, p<0. 05) and lower osmolality ($616{\pm}18\;mOsm/kg\;H_2O$, p<0.05) than the students ($1,505{\pm}67\;ml/day$ and $688{\pm}36\;mOsm/kg\;H_2O$). However, both groups excreted similar amounts of urinary $Na^+$, $K^+$ and total osmolar contents. Free water clearance of the Buddhist nuns was higher(p<0.05) than that of the students but the osmolar clearance was about the same in the two groups. Daily urine output showed good correlation with Na output (r=0.76) and osmolar clearance but not with free water clearance. Both groups showed similar values of plasma concentration of creatinine, daily excretion of creatinine and clearance. Urinary excretion of urea for Buddhist nuns was 6.4 g/day, and was significantly higher than that of the students (5.1g/day).

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.166-173
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• 2010

Purpose : Genetic and clinical factors can influence the permeability of the peritoneal membrane. The peritoneal equilibration test (PET) is helpful in measuring peritoneal permeability in peritoneal dialysis (PD). We investigated the influence of genetic polymorphism of vascular endothelial growth factor (VEGF) on the PET parameters. Methods : Pediatric patients who underwent PET within 12 months of initiating PD at Seoul National University Children's Hospital and Samsung Medical Center were selected. The patients with positive history of peritonitis before PET were excluded. The VEGF -2578C/A, -14978T/C, -1154G/A, -634G/C, and +936C/T single-nucleotide polymorphisms were genotyped. Results : The mean 4-hour dialysate-to-plasma ratio for creatinine (D/P creatinine) and the mean 4-hour dialysate glucose to baseline dialysate glucose ratio (D/$D_0$ glucose) were $0.56{\pm}0.13$ and $0.43{\pm}0.11$, respectively. The patients with haplotype CTGGC showed higher 4-hour D/P creatinine ($0.67{\pm}0.12$ vs $0.50{\pm}0.09$, P=0.007) and lower 4-hour D/$D_0$ glucose ($0.35{\pm}0.12$ vs $0.47{\pm}0.08$, P=0.037) than those without haplotype CTGGC. Conclusion : The VEGF genetic polymorphism may influence the peritoneal solute transport.

• Radiation Oncology Journal
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• v.13 no.4
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• pp.321-330
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• 1995

Purpose : To evaluate whether the early pulmonary irradiation can prevent or decrease the pulmonary damage and contribute to improve ultimate survival in paraquat lung. Materials and Methods : From Jun. 1987 to Aug. 1993, thirty patients with paraquat poisoning were evaluated. Fourteen of these patients were received pulmonary irradiation(RT). All of the patients were managed with aggressive supportive treatment such as gastric lavage, forced diuresis, antioxidant agents and antifibrosis agents. Ingested amounts of paraquat were estimated into three groups(A : minimal 50cc). Pulmonary irradiation was started within 24 hours after admission(from day 1 to day 11 after ingestion of paraquat). Both whole lungs were irradiated with AP/PA parallel opposing fields using Co-60 teletherapy machine. A total of 10Gy(2Gy/fr. x 5days) was delivered without correction of lung density. Results : In group A, all patients were alive regardless of pulmonary irradiation and in group C, all of the patients were died due to multi-organ failure, especially pulmonary fibrosis regardless of pulmonary irradiation. However, in group B, six of 7 patients($86{\%}$) with no RT were died due to respiratory failure, but 4 of 8 patients with RT were alive and 4 of 5 patients who were received pulmonary irradiation within 4 days after ingestion of paraquat were all alive though radiological pulmonary change. One patient who refused RT after 2Gy died due to pulmonary fibrosis. All 3 patients who were received pulmonary irradiation after 4 days after ingestion were died due to pulmonary fibrosis in spite of recovery from renal and hepatic toxicity Conclusion : It is difficult to find out the effect of pulmonary irradiation on the course of the paraquat lung because the precise plasma and urine paraquat concentration were not available between control and irradiation groups. But early pulmonary irradiation within 4 days after paraquat poisoning with aggresive supportive treatment appears to decrease Pulmonary toxicity and contribute survival in patients with mouthful ingestion of paraquat who are destined to have reversible renal and hepatic damage but irreversible pulmonary toxicity.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.710-718
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• 2002

It is reported that Pueraria Radix contains phtoestrogens whereas flower, and bud of Pueraria lobata Ohwi were not known. In the present study, we determined the amount of phytoestrogen in each portion of P. lobata Ohwi and carried out therapeutic effects of osteoporosis. The amounts of genistein, daidzein, and formononetin in Pueraria Radix (PR), Pueraria Flos (PF), and young Pueratia Folium (PL) were quantitated using a HPLC system. Proliferation of osteoblast and growth inhibitory effect on osteoclast were measured in order to screen their effects on osteoporosis. Proliferation of osteoblast-like cells (Saos-2) was analyzed by both MTT methods and alkaline phosphatase (ALP) assays. Growth inhibitory effect on osteoclast was also detected as Tartrate resistant acid phosphatase (TRAP) assay. Ovariectomized rat as an in vivo animal model was selected and administrations of PR were 1 g/kg/day (PR-1) and 5 g/kg/day (PR-5) for 9 weeks, respectively. Trabecular bone areas (TBAs) of tibia and lumbar were analyzed usibg histomorphological methods. Results show that PR contains the highest level of daidzein ($10435{\pm}2143\;mg/kg$ of dried herb) and stimulated ALP activity, approximately 160% of the control. Growth inhibitory effect on osteoclast by both PR and daidzein were almost identical with control although $IC_{50}$ of genistein was $5.81{\times}10^{-7}$ M. Increases in body weight of OVX rats were suppressed by administration of PR but wet weights of uterus in PR-5 group were increased (p<0.05). Plasma ALP and HDL-cholesterol levels were decreased following ages (p<0.01), and LDL-cholesterol level was also decreased in PR-5 group at 20 week of age (p<0.01). TBAs of tibia and lumbar in PR-1 and PR-5 groups were higher than those of the control although the values were less than those of the sham group (each p<0.01) In conclusion, administrations of PR prevented loss of TBAs of tibia and lumber in OVX rats, while PL and PF did not (p<0.01).

• Journal of Yeungnam Medical Science
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• v.14 no.1
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• pp.53-66
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• 1997

Insulin resistance is a prominent feature of diabetic state and has heterogeneous nature. However, the pathogenetic sequence of events leading to the emergence of the defect in insulin action remains controversial. It is well-known that prolonged hyperglycemia and hyperinsulinemia are one of the causes of development of insulin resistance, but both hyperglycemia and hyperinsulinemia stimulate glucose uptake in peripheral tissue. Therefore, it is hypothesized that insulin resistance may be generated by a kind of protective mechanism preventing cellular hypertrophy. In this study, to evaluate whether the acutely increased glucose uptake inhibits further glucose transport stimulated by insulin, insulin sensitivity was measured after preloaded glucose infusion for 2 hours at various conditions in rats. And also, to evaluate the mechanism of decreased insulin sensitivity, insulin receptor binding affinity and glucose transporter 4 (GLUT4) protein of plasma membrane of gastrocnemius muscle were assayed after hyperinsulinemic euglycemic clamp studies. Experimental animals were divided into five groups according to conditions of preloaded glucose infusion: group I, basal insulin ($14{\pm}1.9{\mu}U/ml$) and basal glucose ($75{\pm}0.7mg/dl$), by normal saline infusion; group II, normal insulin ($33{\pm}3.8{\mu}U/ml$) and hyperglycemia ($207{\pm}6.3mg/dl$), by somatostatin and glucose infusion; group III, hyperinsulinemia ($134{\pm}34.8{\mu}U/ml$) and hyperglycemia ($204{\pm}4.6mg/dl$), by glucose infusion; group IV, supramaximal insulin ($5006{\pm}396.1{\mu}U/ml$) and euglycemia ($l00{\pm}2.2mg/dl$), by insulin and glucose infusion; group V, supramaximal insulin ($4813{\pm}687.9{\mu}U/ml$) and hyperglycemia ($233{\pm}3.1mg/dl$), by insulin and glucose infusion. Insulin sensitivity was assessed with hyperinsulinemic euglycemic clamp technique. The amounts of preloaded glucose infusion(gm/kg) were $1.88{\pm}0.151$ in group II, $2.69{\pm}0.239$ in group III, $3.54{\pm}0.198$ in group IV, and $4.32{\pm}0.621$ in group V. Disappearance rates of glucose (Rd, mg/kg/min) at steady state of hyperinsulinemic euglycemic clamp studies were $16.9{\pm}3.88$ in group I, $13.5{\pm}1.05$ in group II, $11.2{\pm}1.17$ in group III, $13.2{\pm}2.05$ in group IV, and $10.4{\pm}1.01$ in group V. A negative correlation was observed between amount of preloaded glucose and Rd (r=-0.701, p<0.001) when all studies were combined. Insulin receptor binding affinity and content of GLUT4 were not significantly different in all experimental groups. These results suggest that increased glucose uptake may inhibit further glucose transport and lead to decreased insulin sensitivity.