BRIEF COMMUNICATION: Effect of growth hormone on the mammary transcriptome profile during established lactation in the dairy cow

摘要

Gene expression profiling studies have provided insights into the potential mechanisms involved in a range of physiological processes in the ruminant mammary gland. However, despite the well established galactopoietic effect of growth hormone (GH) inlactating ruminants (Bauman, 1999; Akers, 2006), the molecular mechanism(s) that mediate the effects of GH on milk production are not fully understood. GH has been implicated in the induction of a-casein gene and protein expression in cultured bovine mammary epithelial cells (Sakamoto et al, 2005) and p-casein inRNA levels are elevated following a 63 day infusion of GH (Yang et al, 2005), while K-casein gene expression is unaffected by GH treatment in lactating dairy goats (Boutinaud & Jammes, 2004). Inaddition to transcription regulation, post-transcriptional regulation of casein mRNA has also been proposed (Zeigler & Wicha, 1992; Yang et al, 2005). Hence, milk protein gene expression levels may be regulated through post-transcriptional mechanisms. The wider effects of GH treatment on the mRNA levels of other genes in the mammary gland of the lactating dairy cow have also not been reported.