Effect of Conjugated Linoleic Acid on Testosterone Levels In Vitro and In Vivo After an Acute Bout of Resistance Exercise

Abstract

and Di Felice, V. Effect of conjugated linoleic acid on testosterone levels in vitro and in vivo after an acute bout of resistance exercise. J Strength Cond Res 26(6): 1667-1674, 2012-The purposes of the present study were to investigate the effect of conjugated linoleic acid (CLA) supplementation on testosterone levels in vitro on a cell line derived from Leydig cells (R2C) and in vivo in the blood of physically active subjects before and after a resistance exercise bout. In vitro R2C cells were treated with different CLA concentrations (0-30 mM) for 24 and 48 hours. After treatment, supernatant media were tested to determine testosterone secretion. The CLA increased the testosterone secretion only after 48 hours. In vivo, 10 resistance-trained male subjects, in a double-blind placebo-controlled and crossover study design were randomized for 3 weeks of either 6 gÁd 21 CLA or placebo. Blood was drawn pre and post each resistance exercise bout to determine the total testosterone and sex hormone-binding globulin (SHBG) levels. No significant differences were observed for total testosterone or SHBG pre and post each resistance exercise bout; although after the resistance exercise bouts, total testosterone increased moderately (effect size = moderate), whereas after CLA supplementation, there was a large increase in total testosterone (effect size = large). CLA supplementation induced an increase in testosterone levels in Leydig cells in vitro after 48 hours but not in vivo before and after a resistance exercise bout. These findings suggest that CLA supplementation may promote testosterone synthesis through a molecular pathway that should be investigated in the future, although this effect did not have an anabolic relevance in our in vivo model.

Endurance Exercise and Conjugated Linoleic Acid (CLA) Supplementation Up-Regulate CYP17A1 and Stimulate Testosterone Biosynthesis

“…The main isomers of CLA are cis-9, trans-11, trans-10, and cis-12 octadecaenoic acids (c9, t11-CLA and t10, c12-CLA) [3]. We have previously shown that CLA treatment stimulates testosterone biosynthesis in the rat Leydig tumour cell line (R2C), although the testosterone pathway stimulated by the CLA treatment was not identified [4]. High levels of testosterone may enhance muscle mass, which is important in sport science to increase maximal voluntary strength [5] and in cachexia and anti-aging therapies to stop muscle wasting [6–8].…”

Effect of Conjugated Linoleic Acid Intake on Endurance Exercise Performance and Anti-fatigue in Student Athletes

“…In this study, the amount of exercise time variation in the CLA group significantly increased compared with the Pla group. CLA supplementation with training increased free testosterone and exercise performance 15,24,27 . Hemoglobin and hematocrit were increased by higher testosterone, and that was associated with increased erythropoietin levels 27,29 .…”

“…Sneddon et al 23 reported that CLA plus n-3 long-chain polyunsaturated fatty acids n-3 LC-PUFA supplementation, 3 g/day CLA plus 3 g/day n-3 LC-PUFA for 12 weeks, has no effect on BMF in young lean male individuals age 30.5 4.9 years, BMI 23.6 1.5 kg/m 2 , body fat 16.1 5.4 . And Macaluso et al 24 reported that there were no significant differences in total body mass, BMF, and LBM by CLA supplementation, 6 g/day for Reduced body fat mass by CLA intake suggested that CLA causes reduction in lipid uptake by adipose cells because of an effect on lipoprotein lipase and stearoyl-CoA desaturase and carnitine palmitoyltransferase activity in muscle cells, which is the rate-limiting enzyme in β-oxidation, is increased 18 . On the other hand, increased muscle mass by CLA intake was suggested by increased serum testosterone level 15,24,27 .…”

“…And Macaluso et al 24 reported that there were no significant differences in total body mass, BMF, and LBM by CLA supplementation, 6 g/day for Reduced body fat mass by CLA intake suggested that CLA causes reduction in lipid uptake by adipose cells because of an effect on lipoprotein lipase and stearoyl-CoA desaturase and carnitine palmitoyltransferase activity in muscle cells, which is the rate-limiting enzyme in β-oxidation, is increased 18 . On the other hand, increased muscle mass by CLA intake was suggested by increased serum testosterone level 15,24,27 . Testosterone can induce increase of energy expenditure by elevating mitochondrial biogenesis in skeletal muscle in mice 28 .…”

Increasing Circulating Testosterone: Impact of Herbal Dietary Supplements

“…Findings from these studies confirm that vitamin D seems to have a direct positive relationship with total testosterone levels and further research is warranted to elucidate the mechanisms of action related to this finding. Vitamin C [92], boron [93], conjugated linoleic acid [84,95], and magnesium [96] are other micronutrients of interest as pertaining to testosterone. Preliminary studies have indicated that these micronutrients may play a role in mediating testosterone levels.…”