Study on Mechanism of Cholesterol Metabolism in Leydig's Cells of Rats with Lower Serum Testosterone due to Intermittent Anaerobic Swimming Training

Abstract

The effect of cholesterol metabolic block of leydig's cell on the testosterone production during is still not well known.PurposeTo compare the effect of different intermittent anaerobic swimming training time on the mRNA expression of HMG‐CoA reductase, SR‐BI, LDL‐R, StAR .MethodsAfter the five‐week intermittent anaerobic swimming training(1 hour per day, with 5% body weight load, TA), TC group stopped training for one week, TD group continue one week training. TE group was trained 2 times per day. TF group was trained with 6% body‐weight load. The serum testosterone (T), the mRNA expression of HMG‐CoA reductase, LDL‐R, SR‐BI and StAR protein in Leydig's cells were examined by the real‐time PCR.ResultThe results showed that the serum T of TA group decreased significantly (1.44±0.42 vs. 8.83±4.57 ng/ml, p<0.01) due to the five‐week training, the LDL‐R mRNA in Leydig's cells increased significantly (p<0.05). Compared with TA group, TC group serum T (4.54±1.60 ng/ml, p<0.01) was increased significantly, but still under the normal level, the SR‐BI mRNA expression in Leydig's cells increased significantly too (p<0.01)l. After one week training, the serum T in TD and TF groups had a further decrease, but their were no significant difference between TA, TD (1.05±0.36 ng/ml) and TF(1.10±0.27, ng/ml) groups. In TE group, there was a further significant decrease in serum T (0.99±0. 29 ng/ml, p<0.05). The LDL‐R mRNA expression, in TD group, had a significantly decrease (p<0.05). In TE, TF groups, the mRNA expression of LDL‐R, SR‐BI, HMG‐CoA reductase in Leydig's cells, were also decreased significantly(p<0.01).ConclusionThe cholesterol metabolic block in Leydig's cells was not the original reason of exercise inducing lower serum testosterone. The decrease of mRNA level of HMG‐CoA reductase, LDL‐R, SR‐BI and StAR in Leydig's cells would accelerate the decrease of serum T due to exercise.