**3.1 Technical verifications**

## **3.1.1 Semiquantitative RT-PCR**

To quantify the levels of OAT and cyclophilin A mRNA by RT-PCR, we determined the appropriate number of amplification cycles to remain in the exponential phase of the amplification process and avoid saturation (Table 1). For each mRNA studied a single RT-PCR product was obtained. The amplified RT-PCR products were of the expected size (Table 1). The level of the mRNA of a housekeeping gene (cyclophilin A) did not vary significantly in our experimental conditions (data not shown).
