Growth hormone mRNA expression in the pituitary of Bos indicus and Bos taurus x Bos indicus crossbred young bulls treated with recombinant bovine somatotropin

• Autor(a) principal: Di Mauro, S. M Z [UNESP]
• Data de Publicação: 2002
• Outros Autores: Furlan, L. R. [UNESP], Ferro, M. I T [UNESP], Macari, Marcos [UNESP], Ferro, J. A. [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://www.geneticsmr.com//year2002/vol1-4/pdf/gmr0036.pdf; http://hdl.handle.net/11449/67113
• topic: Bos indicus; Bos taurus; Bovine pituitary Growth hormone gene expression; Recombinant bovine somatotropin; complementary DNA; growth hormone; growth hormone, bovine; messenger RNA; amino acid substitution; animal experiment; animal tissue; body weight; cattle; comparative study; controlled study; cross breeding; dot hybridization; gene expression; gene sequence; hypophysis; male; molecular cloning; nonhuman; Northern blotting; quantitative analysis; animal; DNA sequence; drug effect; genetics; growth, development and aging; organ size; secretion; Animalia; Bos; Bovinae; Bubalus; Animals; Body Weight; Cattle; DNA, Complementary; Gene Expression; Growth Hormone; Male; Organ Size; Pituitary Gland; RNA, Messenger; Sequence Analysis, DNA

The effects of breed and of recombinant bovine somatotropin (rbST) treatment on growth hormone gene expression were studied in young bulls. The experiment was completely randomized in a [2 × 2]-factorial arrangement, using two levels of rbst (0 or 250 mg/animal/14 days), and two breed groups (Nelore and Simmental x Nelore crossbred). A CDNA encoding Bos indicus growth hormone was cloned and sequenced for use as a probe in Northern and dot blot analyses. Compared to the Bos taurus structural gene, the Bos indicus CDNA was found to begin 21 bases downstream from the transcription initiation site and had only two discrepancies (C to T at position 144-His and T to C at position 354-Phe), without changes in the polypeptide sequence. However, two amino acid substitutions were found for Bubalus spp., which belong to the same tribe. The rbst treatment did not change any of the characteristics evaluated (body and pituitary gland weights, growth hormone MRNA expression level). Crossbred animals had significantly higher body weight and heavier pituitaries than Nelore cattle. Pituitary weight was proportional to body weight in both breed groups. Growth hormone MRNA expression in the pituitary was similar (P>0.075) for both breed and hormonal treatment groups, but was 31.9% higher in the pure Nelore group, suggesting that growth hormone gene transcription regulation differs among these breeds.