Inhibitory actions of activin on GH- and hCG-induced GH gene expression in carp pituitary cells.

<p>(A) Activin A and B treatment on GH-induced GH mRNA expression. Pituitary cells were treated for 48 hr with porcine GH (100 ng/ml) in the presence of human activin A (30 ng/ml) and B (30 ng/ml), respectively. (B) Activin A and B treatment on hCG-induced GH mRNA expression. Pituitary cells were exposed to hCG (40 IU/ml) for 48 hr with/without the co-treatment of human activin A (30 ng/ml) and B (30 ng/ml), respectively. After drug treatment, total RNA was isolated and subjected to real-time PCR for GH mRNA measurement. Data presented are pooled results from four separate experiments (N = 4) and the groups denoted by different letters represent a significant different at P < 0.05 (ANOVA followed by Newman-Keuls test).