The Advantage of Absolute Quantification in Comparative Hormone Research as Indicated by a Newly Established Real‐Time RT‐PCR: GH, IGF‐I, and IGF‐II Gene Expression in the Tilapia, Oreochromis niloticus

A bstract : We have developed a real‐time RT‐PCR that absolutely quantifies the gene expression of hormones using the standard curve method. The method avoids cloning procedures by using primer extension to create templates containing a T7 promoter gene sequence. It is rapid since neither separate reverse transcriptions nor postamplification steps are necessary, and its low detection level (2 pg/μg total RNA) allows precise absolute quantification. Using the method, we have quantified the gene expression of GH, IGF‐I, and IGF‐II in the tilapia.