Clinical Research Directory

Effect of Insulin Lowering on Lipogenesis

The goal of this clinical trial is to compare a one-week course of diazoxide (2 mg/kg per dose x 14 doses) and placebo in people with obesity and insulin resistance (IR) with metabolic dysfunction-associated steatotic liver disease (MASLD). The main question it aims to answer are how mitigation of compensatory hyperinsulinemia with diazoxide affects hepatic de novo lipogenesis, a major contributor to MASLD pathophysiology. Participants will: * Take 14 doses of placebo over 7 days, followed 4-12 weeks later by either 14 doses of diazoxide (at 2 mg per kg of body weight per dose \[mpk\]) or another 14 doses of placebo, over 7 days * Take 18 doses of heavy (deuterated) water (50 mL each) over 7 days, twice * Have blood drawn and saliva collected after an overnight fast on four mornings over the course of the study * Undergo insulin suppression tests (IST) to assess the degree of insulin resistance at the end of each 1-week study period * Consume their total calculated daily caloric needs as divided into three meals per day Researchers will compare blood tests at the beginning and end of each 1-week study period in participants randomized (like the flip of a coin) to receive either placebo followed by diazoxide or placebo followed by placebo, to see how the drug treatment affects de novo lipogenesis, serum insulin, plasma glucose, and other serum lipid parameters (triglycerides, free fatty acids), among others.

Clinical and Molecular Characteristics of Primary Aldosteronism in Blacks

Background: The adrenal gland makes the hormone aldosterone. This helps regulate blood pressure. An adrenal gland tumor that makes too much aldosterone can cause high blood pressure and low potassium. The cause of these tumors is unknown, but sometimes they are inherited. Objective: To study the genes that may cause primary aldosteronism in Black individuals. Eligibility: People ages 18-70 who: Are Black, African American, or of Caribbean descent And have difficult to control blood pressure or primary aldosteronism Relatives of people with primary aldosteronism Design: Participants who are relatives of people with primary aldosteronism will have only 1 visit, with medical history and blood tests. Participants with primary aldosteronism or difficult to control blood pressure (suspected to possibly have primary aldosteronism) will be screened with a 1-2 hour visit. If they qualify, they will return for a hospital stay for 7-10 days. Tests may include: Medical history Physical exam Blood tests: Participants will have a small tube (IV catheter) inserted in a vein in the arm. They may drink a glucose-containing liquid or get a salt solution. If medically indicated, they may have invasive blood tests with a separate consent. Urine tests: Some require a high-salt diet for 3 days. Heart tests Scans: Participants lie in a machine that takes pictures of the body. A dye may be injected through a vein. Small hair sample taken from near the scalp. Kidney ultrasound Bone density scan: Participants lie on a table while a camera passes over the body. If the doctors feel it is medically necessary, they will offer participants treatment depending on their results. These treatments may cure the patient of their disease and may include: 1. Having one adrenal gland removed by the Endocrine surgeon under anesthesia. Patients will have follow-up visits 2-4 weeks after surgery. 2. Taking drugs to block the effects of aldosterone Participants may return about 1 year later to repeat testing.

Reprometabolic Syndrome Mediates Subfertility in Obesity

Obesity plays an adverse role at every stage of conception and pregnancy and mounting evidence implicates relative hypogonadotropic hypogonadism, and reduced menstrual cycle hormone secretion as likely contributors to the subfertility phenotype and possible contributors to complications of pregnancy and the developmental origin of adult diseases such as diabetes and cardiovascular disease. This study will be the first comprehensive investigation to tie together the patterns of hyperinsulinemia, hyperlipidemia and inflammation, characteristic of obesity and obesity-caused relative hypogonadotropic hypogonadotropism and its potential adverse reproductive outcomes. The investigators findings will be used to inform a subsequent clinical intervention to optimize reproductive outcomes for obese women and their offspring.

Human Models of Selective Insulin Resistance: Pancreatic Clamp

This is a single-center, prospective, randomized, controlled (crossover) clinical study designed to investigate the impact of lowering insulin levels on hepatic glucose production (HGP) vs de novo lipogenesis (DNL) in people with insulin resistance. The investigators will recruit participants with a history of overweight/obesity and evidence of insulin resistance (i.e., fasting hyperinsulinemia plus prediabetes and/or impaired fasting glucose and/or Homeostasis Model Assessment of Insulin Resistance \[HOMA-IR\] score \>=2.73), and with evidence of metabolic dysfunction-associated steatotic liver disease (MASLD). Participants will undergo two pancreatic clamp procedures -- one in which serum insulin levels are maintained near hyperinsulinemic baseline (Maintenance Hyperinsulinemia or "MH" Protocol) and the other in which serum insulin levels are lowered by 50% (Reduction toward Euinsulinemia or "RE" Protocol). In both clamps the investigators will use stable-isotope tracers to monitor hepatic glucose and triglyceride metabolism. The primary outcome will be the impact of steady-state clamp insulinemia on HGP vs DNL.

Diazoxide Suppression Test P&F Study

The goal of this study is to learn about how the hormone insulin controls blood sugar. The main question it aims to answer is about how much insulin the body actually needs to maintain a normal blood sugar level. People with obesity and high insulin levels will receive eight doses of diazoxide, a drug that suppresses the pancreas's production of insulin, and will have their fasting blood sugar and insulin levels checked daily while taking the drug.

Graded Insulin Suppression Test P&F

The goal of this study is to learn about how the hormone insulin controls blood sugar in a variety of people. The main question it aims to answer is about how much insulin the body actually needs to maintain a normal blood sugar level. Participants will be asked to come in for a one-day study visit in which they will undergo a "graded insulin suppression test" ("GIST"). The GIST involves intravenous (into the vein) infusions of octreotide, a medication that turns off the body's own production of insulin, as well as replacement of insulin at two different levels (low and high), with or without replacement of glucagon, and glucose (sugar). The study investigators will check blood sugar levels every few minutes during the procedure to determine the effect of the two different insulin levels. This study will evaluate the GIST in both healthy volunteers and those at higher risk for type 2 diabetes.

Effect of a Sugar Replacement on Blood Glucose Levels in Healthy Adults

Diabetes and cardiovascular disease account for millions of deaths per year. One of the risk factors for both conditions is high blood sugar, particularly after eating (postprandial hyperglycaemia). Lowering blood sugar levels after a meal is expected to have a positive effect on preventing metabolic and cardiovascular diseases and improving the metabolic control of those who already suffer from these conditions. The aim of this study is to investigate the effect of Oligomate® (beta-galacto-oligosaccharide) on postprandial glycaemia when used as a partial replacement of glycaemic carbohydrates in a beverage in otherwise healthy volunteers. Volunteers will be given water with either Oligomate® or glucose (control) added. Blood samples will be collected at eight time points (two before drinking the beverage and six after) to measure glucose and insulin levels.

The Movie Theater Study

Increasing attention has been paid to meals with unusual characteristics that are consumed on a semi-regular basis (e.g., "tailgating," pizza buffets). The purpose of this study is to describe the acute cardiometabolic effects of a cinema-style meal rich in refined sugar, total carbohydrate, and moderate in fat (i.e., soda, popcorn, candy).