TY - JOUR
TI - Studies of insulin resistance in patients with clinical and subclinical hypothyroidism
AU - Maratou, E.
AU - Hadjidakis, D.J.
AU - Kollias, A.
AU - Tsegka, K.
AU - Peppa, M.
AU - Alevizaki, M.
AU - Mitrou, P.
AU - Lambadiari, V.
AU - Boutati, E.
AU - Nikzas, D.
AU - Tountas, N.
AU - Economopoulos, T.
AU - Raptis, S.A.
AU - Dimitriadis, G.
JO - European Journal of Endocrinology
PY - 2009
VL - 160
TODO - 5
SP - 785-790
PB - 
SN - 0804-4643, 1479-683X
TODO - 10.1530/EJE-08-0797
TODO - glucose;  glucose transporter 3;  glucose transporter 4;  insulin;  liothyronine;  prolactin;  thyroxine;  glucose transporter 3;  glucose transporter 4;  insulin;  SLC2A3 protein, human;  SLC2A4 protein, human, adult;  article;  cell membrane;  clinical article;  clinical hypothyroidism;  controlled study;  euthyroidism;  flow cytometry;  glucose blood level;  glucose metabolism;  glucose transport;  human;  hypothyroidism;  in vitro study;  in vivo study;  insulin blood level;  insulin resistance;  liothyronine blood level;  monocyte;  oral glucose tolerance test;  priority journal;  prolactin blood level;  subclinical hypothyroidism;  thyroxine blood level;  blood;  cell culture;  comparative study;  diet restriction;  glucose tolerance test;  metabolism;  middle aged;  pathology;  physiology;  thyroid function test, Adult;  Blood Glucose;  Cell Membrane;  Cells, Cultured;  Fasting;  Glucose Tolerance Test;  Glucose Transporter Type 3;  Glucose Transporter Type 4;  Humans;  Hypothyroidism;  Insulin;  Insulin Resistance;  Middle Aged;  Monocytes;  Thyroid Function Tests
TODO - Objective: Although clinical hypothyroidism (HO) is associated with insulin resistance, there is no information on insulin action in subclinical hypothyroidism (SHO). Design and methods: To investigate this, we assessed the sensitivity of glucose metabolism to insulin both in vivo (by an oral glucose tolerance test) and in vitro (by measuring insulin-stimulated rates of glucose transport in isolated monocytes with flow cytometry) in 21 euthyroid subjects (EU), 12 patients with HO, and 13 patients with SHO. Results: All three groups had comparable plasma glucose levels, with the HO and SHO having higher plasma insulin than the EU (P<0.05). Homeostasis model assessment index was increased in HO (1.97±0.22) and SHO (1.99±0.13) versus EU (1.27±0.16, P<0.05), while Matsuda index was decreased in HO (3.89±0.36) and SHO (4.26±0.48) versus EU (7.76±0.87, P<0.001), suggesting insulin resistance in both fasting and post-glucose state. At 100 μU/ml insulin: i) GLUT4 levels on the monocyte plasma membrane were decreased in both HO (215±19 mean fluorescence intensity, MFI) and SHO (218±24 MFI) versus EU (270±25 MFI, P=0.03 and 0.04 respectively), and ii) glucose transport rates in monocytes from HO (481±30 MFI) and SHO (462±19 MFI) were decreased versus EU (571±15 MFI, P=0.04 and 0.004 respectively). Conclusions: In patients with HO and SHO: i) insulin resistance was comparable; ii) insulin-stimulated rates of glucose transport in isolated monocytes were decreased due to impaired translocation of GLUT4 glucose transporters on the plasma membrane; iii) these findings could justify the increased risk for insulin resistance-associated disorders, such as cardiovascular disease, observed in patients with HO or SHO. © 2009 European Society of Endocrinology.
ER -