Thyroid and Fat Tissue Metabolism

NCT00312715 | Completed

• 2 other identifiers: 06013306-DK-0133
• Study Type: observational
• Target: 41
• Locations: 1 country
• Sites: 1

Brief Summary

This study will use a technique called microperfusion to examine how thyroid hormones are involved in fat metabolism. The thyroid gland produces two kinds of hormones: T3 and T4. Some of the T4 is changed to T3 in various organs after leaving the thyroid. The T3 stimulates the body to burn fat. People have different rates at which they can change T4 to T3, and this may lead to differences in body fat among different people. Microperfusion is based on the exchange of substances across tiny holes of a small plastic tube called a "probe," which is inserted after numbing the skin over a fat pad. Through these openings, the fat pad is continuously rinsed with small amounts of fluid, and an exchange of substances occurs. The fluid drips from the other opening of the probe and is collected in a vial. Small amounts of study drugs are infused and the amount of substances released by the fat pad in response to them are measured. Healthy normal volunteers 18 years of age and older may be eligible for this study. Candidates are screened with a medical history, physical examination and blood tests. Participants undergo microperfusion. A needle is placed in an arm vein for collecting blood samples before and at the end of the experiment for measuring thyroid hormones and other substances in the blood. The skin over the fat pad next to the umbilicus (navel) is numbed and two microperfusion probes are inserted. A salt water solution is infused into the fat pad for one hour and the substances in the fluid are measured as the fluid leaves the fat pad. After 1 hour isoproterenol, a drug that aids in energy production by fat, is added to help determine the level of fat metabolism. After an additional hour small amounts of thyroid hormone are added to the fluid and samples are collected as they leave the body. Two catheters are inserted during each experiment. Small volumes of sterile fluid are circulated continuously in the tubing and samples are collected at regular intervals.

Conditions

Healthy Volunteers

Keywords

Deiodinase; Levothyroxine; Liothyronine; Lipid Metabolism; Healthy Volunteer; HV

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age greater than or equal to 18 years, male or female.
• Written informed consent.

You may not qualify if:

• Hypo- or hyper-thyroid (history or TSH greater than 5.0 and less than 0.4 miU/L)
• Blood pressure greater than 140/90 mmHg \[17\] or current antihypertensive therapy
• History of cardiovascular disease
• BMI less than or equal to 20 or greater than or equal to 30 Kg/m(2).
• Diabetes mellitus (serum glucose greater than or equal to 126 mg/dL).
• Hypercholesterolemia (serum levels greater than or equal to 240 mg/dL), hypertriglyceridemia (plasma levels greater than or equal to 220 mg/dL) and/or use of antilipemic therapy.
• Liver disease or ALT serum level greater than two fold the upper laboratory reference limit.
• Renal insufficiency or estimated creatinine clearance less than or equal to 50 mL/min (Cockcroft method).
• History of illicit drug or alcohol abuse within the last 5 years; current use of drugs (by history) or alcohol (CAGE greater than 3).
• Psychiatric conditions or behavior that would be incompatible with safe and successful participation in this study
• Current use of medications/dietary supplements/alternative therapies known to alter thyroid function.
• Allergy to ethanol, levothyroxine, liothyronine, isoproterenol, lidocaine.
• Pregnancy/breastfeeding.
• Current smoker
• All subjects will be fully informed of the aim, nature, and risks of the study prior to giving written informed consent.

Sponsors & Collaborators

• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): lead

Study Sites (1)

National Institutes of Health Clinical Center, 9000 Rockville Pike

Bethesda, Maryland, 20892, United States

Location

Related Publications (3)

• Elks ML, Manganiello VC. Effects of thyroid hormone on regulation of lipolysis and adenosine 3',5'-monophosphate metabolism in 3T3-L1 adipocytes. Endocrinology. 1985 Sep;117(3):947-53. doi: 10.1210/endo-117-3-947.

  PMID: 2410243 BACKGROUND

• Germack R, Starzec A, Perret GY. Regulation of beta 1- and beta 3-adrenergic agonist-stimulated lipolytic response in hyperthyroid and hypothyroid rat white adipocytes. Br J Pharmacol. 2000 Feb;129(3):448-56. doi: 10.1038/sj.bjp.0703008.

  PMID: 10711342 BACKGROUND

• Mentuccia D, Proietti-Pannunzi L, Tanner K, Bacci V, Pollin TI, Poehlman ET, Shuldiner AR, Celi FS. Association between a novel variant of the human type 2 deiodinase gene Thr92Ala and insulin resistance: evidence of interaction with the Trp64Arg variant of the beta-3-adrenergic receptor. Diabetes. 2002 Mar;51(3):880-3. doi: 10.2337/diabetes.51.3.880.

  PMID: 11872697 BACKGROUND

Study Officials

• Francesco S Celi, M.D.

  National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Sponsor Type: NIH

Study Record Dates

• First Submitted: April 8, 2006
• First Posted: April 10, 2006
• Study Start: April 3, 2006
• Study Completion: July 8, 2014
• Last Updated: October 6, 2017

Record last verified: 2014-07-08

Locations

US (1)