Age-related changes in gene expression of the growth hormone secretagogue and growth hormone-releasing hormone receptors in Holstein-Friesian cattle

摘要: Growth hormone secretion from the anterior pituitary gland is controlled by interactions between three receptors, GHRH and receptor (GHRH-R), ghrelin growth secretagogue (GHS-R1a), somatostatin receptors in hypothalamus gland. Ghrelin-GHS-R1a involved many important functions, including GH appetite. We investigated age-related changes expressions of GHS-R1a, GHS-R1b (the truncated-type receptor), GHRH-R mRNAs real-time reverse transcription-PCR using 16 tissues, leukocytes, oocytes, cumulus cells Holstein-Friesian cattle. The tissue samples were divided into age classes: 1) 19 to 26 d (preweaning calves), 2) 2 mo 6.5 (postweaning 3) 3.2 8.1 yr (cows). GHS-R1a mRNA was highly (P 10-fold greater < 0.01) than those preweaning calves cows, its expression level greatest all tissues examined group 2. tended be 0.20 P 0.17, respectively) postweaning cows. detected examined, abundance 0.05) pancreas, gland, spleen, arcuate nucleus, adipose tissue, leukocyte compared with that other 3. Interestingly, a relatively large animal-to-animal variation observed pancreas GHS-R 1b expression. markedly increased groups tissues. liver, heart not mammary nonlactating