The regulation of stearoyl-CoA desaturase gene expression is tissue specific in chickens

Abstract

Emerging evidence suggests a potential role of stearoyl-CoA desaturase (SCD)-1 in the control of body weight and energy homeostasis. The present study was conducted to investigate the effects of several energy balance-related factors (leptin, cerulenin, food deprivation, genotype, and gender) on SCD gene expression in chickens. In experiment 1, 6-week-old female and male broiler chickens were used. In experiment 2, two groups of 3-week-old broiler chickens were continuously infused with recombinant chicken leptin (8 mg/kg/h) or vehicle for 6 h. In experiment 3, two groups of 2-week-old broiler chickens received i.v. injections of cerulenin (15 mg/kg) or vehicle. In experiment 4, two broiler chicken lines (fat and lean) were submitted to two nutritional states (food deprivation for 16 or 24 h and feeding ad libitum). At the end of each experiment, tissues were collected for analyzing SCD gene expression. Data from experiment 1 showed that SCD is ubiquitously expressed in chicken tissues with highest levels in the proventriculus followed by the ovary, hypothalamus, kidney, liver, and adipose tissue in female, and hypothalamus, leg muscle, pancreas, liver, and adipose tissue in male. Female chickens exhibited significantly higher SCD mRNA levels in kidney, breast muscle, proventriculus, and intestine than male chickens. However, hypothalamic SCD gene expression was higher in male than in female (P!0 . 05). Leptin increased SCD gene expression in chicken liver (P!0 . 05), whereas cerulenin decreased SCD mRNA levels in muscle. Both leptin and cerulenin significantly reduced food intake (P!0 . 05). Food deprivation for either 16 or 24 h decreased the hepatic SCD gene expression in fat line and lean line chickens compared with their fed counterparts (P!0 . 05). The hypothalamic SCD mRNA levels were decreased in both lines only after 24 h of food deprivation (P!0 . 05). In conclusion, SCD is ubiquitously expressed in chickens and it is regulated by leptin, cerulenin, nutritional state, and gender in a tissue-specific manner.

Stearoyl-CoA Desaturase-1 Is Associated with Insulin Resistance in Morbidly Obese Subjects

“…Moreover, our results also show lower mRNA expression levels in SAT from morbidly obese patients and controls than in VAT. Thus, SCD1 mRNA expression in humans may differ according to the tissue examined, as has been found in animals (18) and with other genes (17), and may suggest a different regulation of SCD1 mRNA expression in VAT and SAT. SCD1 mRNA expression is also highly regulated by fasting/refeeding.…”

“…Besides, mRNA expression may differ according to the tissue examined (17,18). Different studies have shown the regulation of SCD1 synthesis and activity (14)(15)(16)(17)(18).…”

Acute cold‐ and chronic heat‐exposure upregulate hepatic leptin and muscle uncoupling protein (UCP) gene expression in broiler chickens

“…Mammalian adipocytes produce and secrete more leptin in bloodstream as fat storage increases (Maffei et al,'95) signaling the brain via leptin receptor (Schwartz et al,'96) and modulating hypothalamic feeding-related neuropeptides to suppress appetite and increase energy expenditure (Friedman and Halaas,'98). Surprisingly, leptin specifically inhibits the expression of mammalian lipogenic genes such as fatty acid synthase (FAS, a key enzyme in lipogenesis) (Fukuda et al,'99) and stearoyl-CoA desaturase (SCD, the rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids from saturated fatty acids) (Cohen et al, 2002), but not in chickens (Dridi et al, 2005(Dridi et al, , 2007 suggesting species-related differences in fat metabolism and deposition.…”

Recent Progress in Avian Leptin Research

“…Acetylcoline-induced insulin secretion is suppressed by leptin in chicken pancreatic islet cells (Benomar et al, 2003), and insulin reduces LEPR mRNA expression in chicken hepatoma cells (Cassay et al, 2003). Leptin increases mRNA expression of FAS (Dridi et al, 2005) and stearoyl-CoA desaturase (Dridi et al, 2007) in the liver of broilers. Furthermore, in ovo leptin administration upregulates mRNA expression of sterol regulatory element binding protein-1 (SREBP-1c), SREBP-2, hydroxyl-3-methylgulutaryl coenzyme A reductase, and cholesterol 7a hydroxylase 1 at hatching.…”