Growth Hormone Signaling in the Regulation of Acid Labile Subunit

Abstract

GrowthSeveral hormones are important for normal postnatal growth, but it is generally accepted that GH is the most important hormone in this respect. A major portion of the effects of GH on growth is mediated by IGF-I. GH stimulates growth by stimulating liver production of IGF-I, which in turn stimulates longitudinal bone growth in an endocrine manner (Daughaday et al., 1972;Daughaday and Rotwein, 1989). In contrast, GH is not essential for prenatal growth and development, as shown by the existence of normal-sized infants with either congenital absence of the pituitary or deletions of the genes encoding GH or the GH receptor (GHR) (Laron, 1993;Takahashi et al., 1996).Knock-out of the IGF-I and IGF-I receptor in mice has demonstrated that the IGF-I signaling pathway is very important for tissue development and growth. IGF-I knockout mice suffer from a 40% growth deficit at birth and nearly all die within a few hours. Surviving mice suffer from severe growth retardation despite markedly increased circulating GH (

Modulation of the Somatotropic Axis in Periparturient Dairy Cows

“…In addition, GH antagonizes insulin action in several tissues and regulates a nutrient partitioning effect. GH activity can be regulated at the level of growth hormone receptor (GHR) or intracellular signal transduction and with catabolic situations such as parturition, malnutrition, infection and disease occurrence may lead to a state of GH resistance ( Kopchick and Andry, 2000 ; Lucy et al, 2001 ; Zhu et al, 2001 ; Kim and Boisclair et al, 2008 ). GH resistance is characterized by reduced circulating IGF-I despite unchanged or increased plasma GH level.…”

The Endocrine Regulation of Chicken Growth

“…ALS in most species has a molecular weight of 84-86 kDa, and is found as a 150 kDa noncovalent complex in the vascular compartment. This complex consists of one molecule each of IGFs, IGFBP-3 or 5 and ALS (Kim and Boisclair, 2008). In mammals, the structure of ALS gene is composed of 2 exons separated by 1 intron, and spans ~3.3 kb.…”

“…Indirectly, GH binds GH receptor (GHR) on the membrane of liver and then activates hepatic insulin-like growth factor-I (IGF-I) secretion, which stimulates the differentiation and proliferation of bone and muscle cells (McMurtry et al, 1997;Kuhn et al, 2002). In the vascular system, most of IGF circulate in ternary complexes composed of one molecule each of IGF, IGF binding protein (IGFBP) and acid labile subunit (ALS) (Kim and Boisclair, 2008). Although, the action of IGF-II during chicken development and growth has not been established, and is not under direct control of the somatotropic axis, IGF-II has a high affinity for IGF-I receptor and may regulate endocrine and paracrine effects on chicken growth (Duclos and Goddard, 1990;Armstrong and Hogg, 1994).…”

Ghrelin Gene Polymorphisms and Expression Bond With Some Growth and Carcass Traits of Ross 308 Broiler Chickens

“…During last three decades was found that gene polymorphisms can be adopted in genetic improvement and obtaining good production traits in organisms, so recently many candidate genes were used in improving physiological functions and productive performance in different poultry species ( 3,4,1). Endocrine system has involved in regulation growth of chicken by several pathways such as somatotropic and thyrotrophic axis, insulin like growth factor (IGF-1), insulin like growth factor binding protein (IGFBP) ( 6,5,14,2). Somatotroph is one of the cell types that existed in the anterior pituitary gland, which are considered the major site of growth hormone (GH) secretion ( 24,7 ) .…”