Search Results

You are looking at 1 - 5 of 5 items for

  • Author: K M Choi x
Clear All Modify Search
Restricted access

M. Rajalakshmi, D. M. Robertson, S. K. Choi and E. Diczfalusy

ABSTRACT

An in vitro bioassay method for measuring LH activity was applied to male plasma. This method is based on the specific testosterone response to LH activity by interstitial cells from mouse testes. In contrast to assays conducted on female plasma, non-parallel response lines were obtained between serial dilutions of untreated male plasma and the International Reference Preparation for Human Pituitary Gonadotrophins (FSH and LH/ICSH) for bioassay (code no. 69/104). In an attempt to eliminate this source of error, which would invalidate the assays, plasma was subjected to either ether extraction or charcoal adsorption prior to assay. While ether extraction was ineffective, charcoal treatment eliminated the source of non-parallelism. Evidence is presented indicating that the inclusion of a charcoal pre-treatment step provides an assay method for LH which fulfils the recognized criteria of reliability when applied to male plasma.

An investigation of the likely causes of non-parallelism was undertaken by incubating mouse interstitial cells with various steroids and steroid sulphates at concentrations likely to be present in plasma. While most of the presumed precursors of testosterone were converted to testosterone, steroid sulphates (dehydroepiandrosterone sulphate and pregnenolone sulphate) at high concentrations as present in male plasma were the most active compounds in forming testosterone. However, the amount of testosterone produced from these precursors under controlled conditions was insufficient to account entirely for the deviation from parallelism observed with male plasma. Hence, the non-parallelism observed with untreated plasma samples cannot be entirely explained by the presence of steroidal testosterone precursors in male plasma.

Free access

S G Kim, H Y Kim, J A Seo, K W Lee, J H Oh, N H Kim, K M Choi, S H Baik and D S Choi

Objectives: We aimed to investigate the relationship between nonalcoholic fatty liver disease (NAFLD), serum adiponectin concentration and brachial-ankle pulse wave velocity (baPWV) as a risk marker for atherosclerosis.

Methods: A total of 213 nonalcoholic subjects (67 males, 146 females) participated in this study. Division of subjects into the NAFLD group or the normal group was based on the existence of fatty liver detected by sonography.

Results: Serum adiponectin levels in the NAFLD group were significantly lower than those in the normal group. After adjusting for age, body-mass index (BMI) and the homeostasis model of assessment (HOMA), there was a significant negative correlation between NAFLD and serum adiponectin level only in females (r = −0.22, P = 0.008). Multiple logistic regression analysis showed a tendency of inverse correlation between NAFLD and serum adiponectin level in females (P = 0.055). After adjustment for age, BMI and HOMA value, serum adiponectin levels were inversely correlated with serum alanine aminotransferase (ALT) and gamma-glutamyltranspeptidase (GGT) levels (r = −0.199 (P = 0.004) and r = −0.282 (P < 0.001)). On the other hand, baPWV in the NAFLD group was also significantly higher than that in the normal group in females (P = 0.005). Individual levels of serum ALT, aspatate aminotransferase (AST), alkaline phosphatase (ALP) and GGT were positively correlated with baPWV after adjusting for age, sex, BMI, HOMA and systolic blood pressure (P < 0.05).

Conclusion: Serum adiponectin level and baPWV were significantly associated with NAFLD and various liver enzymes, especially in females.

Restricted access

D. M. Robertson, H. Suginami, H. Hernandez Montes, C. P. Puri, S. K. Choi and E. Diczfalusy

ABSTRACT

The presence of an hCG-like material in urinary and pituitary extracts and plasma obtained from non-pregnant subjects was investigated. Two assay methods were used to detect this material following fractionation of pituitary and urinary extracts by gel filtration (Ultrogel AcA 54) and/or isoelectrofocusing: a) a radioimmunoassay employing an antiserum raised against a specific sequence of the carboxy terminal region (residues 115– 145) of the β-subunit of hCG, and b) an in vitro bioassay method which measures both hLH and hCG activities. The fractionation procedures employed provide a satisfactory separation of highly purified hCG and hLH preparations.

In the pituitary and urinary extracts hCGβ-peptide-like immunoactive (PIA) material was found consistently, which co-eluted with iodinated hCG following gel filtration and possessed pI values similar to those of hCG when subjected to isoelectrofocusing. The PIA material also exhibited in vitro biological activity similar to that shown by hLH and hCG. Detectable levels of immunoactive material were also found in plasma; however, the plasma levels of this PIA material were not influenced by classical endocrine measures such as the stimulation or inhibition of gonadotrophin secretion. The low levels of this material in plasma precluded its further characterization by gel filtration or electrofocusing.

Whereas the present data and those reported by other investigators seem to suggest the presence of some hCG-like material in urinary and pituitary extracts and possibly in plasma of non-pregnant subjects, it is emphasized that the available evidence is not sufficiently conclusive to exclude other interpretations as to the nature of this material.

Free access

K M Choi, J S Lee, E J Kim, S H Baik, H S Seo, D S Choi, D J Oh and C G Park

Objectives

Visfatin and lipocalin-2 are novel adipokines associated with insulin resistance (IR) and obesity-related metabolic disorders. We compared lipocalin-2 and visfatin concentrations between patients with coronary heart disease (CHD) and control subjects and evaluated their association with cardiovascular risk factors.

Methods

We examined serum visfatin, lipocalin-2 levels, and cardiovascular risk factors in 91 subjects (49 patients with angiographically confirmed CHD versus 42 age- and gender-matched control participants).

Results

Circulating lipocalin-2 levels were significantly higher in patients with CHD compared with the control subjects (82.6±38.7 ng/ml versus 43.8±27.8 ng/ml; P<0.001). However, visfatin levels were not significantly different between patients with CHD and control subjects. Serum lipocalin-2 levels were positively associated with weight (r=0.26; P=0.036), fasting insulin (r=0.36; P=0.003), and IR (r=0.33; P=0.007), whereas these levels showed a negative correlation with high-density lipoprotein (HDL) cholesterol (r=−0.30; P=0.016) after adjustment for gender and body mass index. However, visfatin levels were not associated with any variables of the metabolic syndrome. The multiple regression analysis showed that lipocalin-2 levels were independently associated with HDL cholesterol and IR (R 2=0.199). Furthermore, the multiple logistic regression analysis showed that systolic blood pressure, IR, and lipocalin-2 levels were independently associated with CHD.

Conclusions

Serum lipocalin-2 levels were significantly elevated in patients with CHD and were independently associated with CHD. The present findings suggest that the measurement of serum lipocalin-2 levels may be useful for assessing CHD risk.

Free access

K M Choi, J H Kim, G J Cho, S H Baik, H S Park and S M Kim

Objective: Visfatin, a novel adipokine, was revealed to be associated with obesity and to have insulin-mimetic effect. Eotaxin, which is an important chemokine in asthma, was recently reported to be associated with obesity in mice and humans. We evaluated the effect of exercise training on plasma visfatin and eotaxin levels in association with cardiovascular risk factors.

Design: Forty-eight non-diabetic Korean women were evaluated before and after a 12 week exercise program including aerobic exercise (45 min/session, 300 Kcal/day) and muscle strength training (20 min/session, 100 Kcal/day) five times per week.

Results: Plasma visfatin concentrations were elevated in obese subjects (body mass index, BMI≥25 kg/m2) when compared with non-obese subjects (16.4 ± 13.4 ng/ml vs 7.7 ± 5.2 ng/ml, P = 0.006), and eotaxin concentrations were elevated in subjects with central obesity (waist circumference, WC≥80 cm) when compared with those without central obesity (73.6 ± 17.8 pg/ml vs 64.2 ± 4.2 pg/ml, P = 0.005). In multiple regression analyses, visfatin levels were associated with BMI (R 2 = 0.255) and eotaxin levels were associated with WC and body weight (R 2 = 0.307). After the exercise program, body weight, blood pressure, fasting glucose, and insulin resistance of participants were decreased. Furthermore, plasma visfatin levels were significantly decreased from 13.6 ± 12.0 to 7.7 ± 7.9 ng/ml (P = 0.026) and eotaxin levels were reduced from 72.0 ± 16.7 to 66.9 ± 14.2 pg/ml (P = 0.018).

Conclusions: Exercise training with weight loss induced a significant reduction of plasma visfatin and eotaxin levels in non-diabetic Korean women.