Substrate Metabolism, Growth Hormone Signaling, and Insulin Sensitivity During Fasting
HealthyBackground: Calorie restriction increases longevity in many species and attenuate the development of chronic disorders including type 2 diabetes, cardiovascular diseases and cancer. In mice reduced activity of insulin-like growth factor I (IGF-I) and/or insulin is associated with extended longevity. Growth hormone (GH) is the main regulator of IGF-I production, but the molecular mechanism whereby GH switches from IGF-I stimulation (protein anabolism) to fatty acid oxidation (fatty acid catabolism) as well as induction of insulin resistance during fasting remains enigmatic. Hypotheses: The changes of the global set of metabolites, induction of insulin resistance, and the shift in metabolism from protein anabolism to lipolysis together with the potentially favorable effect of calorie restriction during fasting depend on preserved fasting-induced GH secretion. Aim: The investigators wish to provide knowledge on changes in metabolites and shift in signaling pathways that take place at the transition to the fasting state among healthy overweight and obese subjects. Furthermore the investigators wish to determine the effect of GH on the adaption of the metabolism to a fasting state.
Protection Against Insulin Resistance in Obesity
ObesityInsulin ResistanceThe overall goal of this project is to identify factors that "protect" some obese adults from becoming insulin resistant. Identifying mechanisms that help protect some obese adults from developing insulin resistance could lead to novel, targeted therapeutic and/or preventative strategies for obese adults who are insulin resistant.
Effect of Apelin on Insulin Sensitivity in Type 2 Diabetic Volunteers
DiabetesPreclinical studies have demonstrated in mouse models that (PYR1)-apelin-13 exerts a glucose-regulating action in vivo. The (PYR1)-apelin-13 effect on insulin sensitivity in healthy overweighed volunteers has been previously assessed in a phase I clinical trial (APELINS study; NCT02033473). The APELINS-2 clinical trial aims to expand the initial proof of concept to the population targeted by future innovative insulin-sensitizing therapies: patients living with type 2 diabetes.
Lipolytic Effects of GH in Hypopituitary Patients in Vivo
HypopituitarismInsulin Resistance5 moreGrowth hormone (GH) is essential for longitudinal bone growth and somatic development. These protein anabolic effects require sufficient nutritional supply. During fasting and caloric restriction GH predominantly promotes fat metabolism. GH counteracts the effect of insulin in many tissues, of which insulin-stimulated glucose uptake in skeletal muscle has been most extensively studied. Substrate competition between elevated free fatty acids and glucose is suggested as a mechanism, and this hypothesis can be tested mechanistically by means of acipimox, which is a nicotinic acid that suppresses the fat metabolizing effects of GH. The hypothesis is, that the suppressive effect of GH on insulin-stimulated glucose uptake in skeletal muscle is obviated by acipimox-induced inhibition of fat metabolism. In order to investigate this, eight adult hypopituitary patients with documented GH-deficiency will be studied in the presence and absence of GH and acipimox, respectively, and biopsies from skeletal muscle and subcutaneous adipose tissue will be analyzed. Knowledge of the effects of growth hormone and fat metabolism can in shot-sight as well as in long-sight have great importance for the understanding of growth disorders from overweight and type 2 diabetes to malnutrition and eating disorders.
The Effect of a Bifidobacterium and Polydextrose on Body Fat Mass
ObesityHyperglycemia1 moreObesity is a major problem worldwide, and it is related to abnormalities in glucose and lipid metabolism. The purpose of this study is to investigate the effect of a dietary supplement containing probiotic (Bifidobacterium animalis ssp. lactis 420) and/or prebiotic (Litesse) on change in body fat mass in a double-blind, randomized, placebo-controlled intervention trial. The supplement is ingested once per day for the duration of six months, and participants will attend a follow-up visit one month after the end of the intervention. The study will enroll 232 participants (58 per study arm) in four research centers in southern Finland.
Effects of Sugar Sweetened Beverage on Metabolic Health in Male and Female Adolescents
Insulin SensitivityInsulin ToleranceWe examined the effects of short-term (2-wk) consumption of HF- and HG-sweetened beverages in adolescents (15-20 yr of age) on insulin sensitivity, insulin secretion, insulin clearance, triacylglycerol (TAG), and cholesterol concentrations.
The Effect of Pharmacological Antilipolysis on the Metabolic Effects of Ghrelin
MetabolismInsulin Resistance1 moreThis study will investigate the non-growth-hormone-dependent metabolic effects of the hormone Ghrelin in growth hormone deficient subjects by examining the insulin tolerance as well as signal proteins in fat and muscle biopsies.
The Effects of Orange Juice on Insulin Sensitivity and Plasma Lipids
Insulin ResistanceObesityThe aim of this study is primarily to investigate the ability of antioxidants found in orange juice (OJ) to increase the body's sensitivity to the hormone insulin. Overweight or mildly obese women, who are otherwise healthy, will be recruited. The time commitment for subjects is ~14wks. Subjects will attend the laboratory on 5 occasions after fasting from midnight. The 1st is a medical screening. Laboratory visits 2 & 5 will take ~5hrs and will be separated by 3 months, during which time subjects will consume 250ml of an orange drink (either OJ or an orange flavoured control drink) once a day. During visits 2 & 5, subjects will have a scan to assess their %body fat using a low-dose x-ray machine, and have their insulin sensitivity measured using a technique called a 'Glucose Clamp'. During the 3hr glucose clamp, subjects receive an infusion of the hormone insulin and a glucose solution directly into their blood stream, with insulin sensitivity determined from the amount of glucose required to maintain blood glucose at normal levels. In addition, a small sample of fat tissue (about the size of a haricot bean) will be taken from underneath the skin of the belly. Subjects will record their food intake for 3-days in weeks 3, 7 and 11 of consuming the drink, and come to the lab for visits 3&4 during weeks 4&8. Laboratory visits 3&4 repeat measurements taken in the 1st (screening) visit.
Safety and Tolerability of BVS857 in Subjects With Insulin Resistance
Insulin ResistanceThe study will assess the safety, tolerability, drug label and effect in subjects with and without insulin resistance.
Effects of Calorie Restriction on Accumulation of Old, Modified Proteins in Abdominally Obese Adults...
Insulin ResistanceThis study is being done to understand the effects of calorie restriction and weight loss on muscle protein metabolism in adult men and women.