Effects of growth hormone administration and dietary protein intake on insulin-like growth factor I and growth hormone receptor mRNA expression in porcine liver, skeletal muscle, and adipose tissue

• Published in: Journal of animal science Vol. 74; no. 8; p. 1832
• Main Authors: Brameld, J.M. (University of Nottingham, Loughborough, Leicestershire, UK.), Atkinson, J.L, Saunders, J.C, Pell, J.M, Buttery, P.J, Gilmour, R.S
• Format: Journal Article
• Language: English
• Published: United States 01.08.1996
• Subjects: Adipose Tissue - chemistry; Adipose Tissue - metabolism; Animals; ARN MENSAJERO; ARN MESSAGER; AZUCAR EN SANGRE; Blood Glucose - analysis; Carrier Proteins - genetics; Carrier Proteins - metabolism; Carrier Proteins - physiology; CERDO; CORPS GRAS ANIMAL; DIETA; Dietary Proteins - pharmacology; Exons; EXPRESION GENICA; EXPRESSION DES GENES; FACTEUR DE CROISSANCE IGF; FACTOR DE CRECIMIENTO IGF; FOIE; Gene Expression Regulation; GRASAS ANIMALES; Growth Hormone - pharmacology; HIGADO; INGESTION DE PIENSOS; Insulin - blood; Insulin-Like Growth Factor I - analysis; Insulin-Like Growth Factor I - genetics; Insulin-Like Growth Factor I - metabolism; Liver - chemistry; Liver - metabolism; Male; MUSCLE; Muscle, Skeletal - chemistry; Muscle, Skeletal - metabolism; MUSCULOS; PESO; PLASMA SANGUIN; PLASMA SANGUINEO; POIDS; PORCIN; PRISE ALIMENTAIRE (ANIMAUX); PROTEINAS; PROTEINAS AGLUTINANTES; PROTEINE; PROTEINE DE LIAISON; Random Allocation; RECEPTEUR D'HORMONE; RECEPTORES DE HORMONAS; Receptors, Somatotropin - analysis; Receptors, Somatotropin - genetics; Receptors, Somatotropin - metabolism; REGIME ALIMENTAIRE; RNA, Messenger - analysis; RNA, Messenger - genetics; RNA, Messenger - metabolism; SOMATOTROPINA; SOMATOTROPINE; SUCRE DU SANG; Swine - genetics; Swine - metabolism; TEJIDO ADIPOSO; TISSU ADIPEUX; Transcription, Genetic
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/1996.7481832x

The effects of growth hormone (GH) and dietary protein on expression of IGF-I and GH receptor (GHR) genes in liver, muscle, and fat of pigs were investigated. Forty-eight intact male Large White X Landrace pigs were allotted to eight treatment groups (four diets with or without GH). The pigs were restriction-fed one of four diets, which differed only in their protein content (9.9, 13.1, 16.2, and 19.4%, as-fed basis), for a total of 3 wk. The pigs were then injected intramuscularly with either porcine GH (50 microgram.kg-1.d-1 of rpST) or vehicle for the last 7 d. Pigs were slaughtered 4 h after the final injection. Total RNA was extracted from all tissues and then RNase protection assays were performed to measure expression of IGF-I and GHR genes. Expression of IGF-I mRNA was found to be GH responsive in the liver, semitendinosus (ST), and adipose tissue (P 0.01) but not in longissimus muscle (LD). Dietary protein increased IGF-I expression only in the adipose tissue (P 0.01). Expression of class 2 transcripts of IGF-I were observed only in the livers of GH-treated pigs, with no effect of dietary protein. Expression of GHR mRNA was found to increase with GH administration in liver and skeletal muscle (LD and ST, P 0.05) but not in adipose tissue. There were diet X GH interactions on GHR expression in liver, ST, and adipose tissue, resulting in the highest GHR expression being in the high protein-fed, GH-treated group for liver, but in the low protein-fed, GH-treated group for muscle and adipose tissue. This study demonstrates tissue-specific control of expression of the two genes and also tissue-specific promoter usage (IGF-I exon 2 in liver) in response to GH administration