Effect of exercise training on A-FABP, lipocalin-2 and RBP4 levels in obese women

OBJECTIVE

Lipocalin family proteins, including adipocyte fatty acid-binding protein (A-FABP), lipocalin-2 and retinol-binding protein 4 (RBP4), have recently been identified as novel adipokines associated with obesity, type 2 diabetes and the metabolic syndrome. We have evaluated the effect of exercise training on lipocalin family proteins and inflammatory markers.

STUDY SUBJECTS

Thirty obese Korean women and 15 age-matched nonobese control subjects were studied.

DESIGN

Concentrations of the lipocalin family proteins were compared between obese and nonobese women and were evaluated before and 3 months after an exercise programme consisting of aerobic exercise (45 min/session, 300 kcal/day) and muscle strength training (20 min/session, 100 kcal/day) five times a week.

RESULTS

Obese women exhibited higher A-FABP levels compared to nonobese women (21.4 +/- 6.4 microg/l vs. 13.6 +/- 4.4 microg/l, P < 0.001). However, neither lipocalin-2 nor RBP4 levels were significantly different between the two groups, although the difference in lipocalin-2 was marginally significant (P = 0.054). Circulating A-FABP levels were significantly associated with body mass index (BMI), waist circumference, triglyceride, alanine aminotransferase (ALT), lipocalin-2 and high-sensitivity C-reactive protein (hsCRP) levels. After 3 months of the exercise training programme, serum A-FABP levels decreased significantly from 21.4 +/- 6.4 microg/l to 19.3 +/- 6.8 microg/l (P = 0.038), along with a reduction in weight, BMI, waist circumference, fasting glucose and total cholesterol levels. There was no significant change in the lipocalin-2 and RBP4 levels, although IL-6 levels increased after the exercise programme.

CONCLUSION

Exercise training with weight loss induced a significant reduction in circulating A-FABP levels in obese Korean women.

The control of ribosomal RNA transcription in lymphocytes. Evidence that the rate of chain elongation is the limiting factor

During activation of lymphocytes by phytohaemagglutinin, the nuclear activity of RNA polymerase I increases with no proportional increase in the amount of catalytic efficiency of the enzyme in the cell. The mechanism by which rRNA transcription in lymphocytes is modified by phytohaemagglutinin stimulation was investigated. The following results were obtained. (a) In resting lymphocytes all RNA polymerase II molecules are bound to the template while a pool of excess free RNA polymerase I, not engaged in transcription, can be detected by its ability to transcribe added poly[d(A-T)]. (b) Although the free RNA polymerase I activity increases twofold to threefold during phytohaemagglutinin stimulation, there is no evidence that the free enzymes ever become engaged in transcription. (c) Most of the RNA chains in elongation in nuclei from resting lymphocytes are being elongated by class II RNA polymerase and their rate of elongation is much higher than that of other RNA species. (d) The same number of pre-rRNA chains are in the process of being elongated in nuclei from resting and stimulated lymphocytes. However, the rate of elongation of pre-rRNA, which is slow relative to the average in resting lymphocytes, increases twofold to threefold within 6 h of phytohaemagglutinin stimulation and rises to sixfold by 19 h. These results suggest that the control of rRNA transcription in phytohaemagglutinin-stimulated lymphocytes lies in the elongation step of transcription rather than in initiation, and that little or no additional rRNA template is transcribed in phytohaemagglutinin-stimulated lymphocytes.

[DNA-dependent RNA polymerases in human leukocytes. II different specific activities of the polymerases A and B in acute and chronic leukemia and their prognostic relevance (author's transl)]

Specific Activities of DNA-dependent RNA polymerases A and B have been determined in nuclei from leukocytes in acute and chronic leukemia. Enzyme activities, dependent on exogenous DNA template, were determined in homogenates of nuclei from isolated mononuclear cells or from isolated granulocytes. Activities of polymerases A and B have been found significantly elevated in homogenates of nuclei from mononuclear cells in acute myelocytic leukemia, while they were found subnormal in corresponding cell fractions from chronic myelocytic leukemia and chronic lymphatic leukemia. During cytostatic treatment polymerase activities were approaching normal values. The prognostic relevance of these data for the course of human leukemia is discussed.