The ratio of leptin to adiponectin can be used as an index of insulin resistance.
The level of leptin increases with obesity, whereas that of adiponectin decreases with obesity. It is reported that the ratio of leptin to adiponectin (L/A) is associated with insulin resistance. It is difficult to evaluate insulin resistance in diabetic patients who have a dysfunction of insulin secretion. The aim of this study was to examine whether the L/A ratio is a useful marker for insulin resistance in diabetic patients. We examined L/A in the serum of a total of 139 Japanese patients with type 2 diabetes mellitus (66 women and 73 men) and 7 healthy individuals recruited in our hospital. Changes in the levels of leptin and adiponectin were observed using the oral glucose tolerance test and a hyper- and euglycemic clamp test. Twenty-one patients with type 2 diabetes mellitus were observed for more than 6 months after treatment with pioglitazone, and 31 patients with type 2 diabetes mellitus were observed for more than 6 months after the treatment with metformin. The mean value of L/A in 139 Japanese patients with type 2 diabetes mellitus was 1.22 +/- 1.41 (1.68 +/- 1.76 in women, 0.81 +/- 0.80 in men; P = .0002). In the clamp tests, L/A correlated with glucose infusion rate (GIR) (r(2) = 0.26, P = .0034). The correlation of L/A and GIR indicated a stronger correlation than either leptin (r(2) = 0.144, P = .03) or adiponectin alone (r(2) = 0.023, P = .41), or the homeostasis model assessment of insulin resistance (r(2) = 0.103, P = .08). The average hemoglobin A(1c) (HbA(1c)) improved from 10.2% +/- 1.2% to 9.2% +/- 1.6% (P = .0037) in 6 months after treatment with pioglitazone. Our results indicate pioglitazone to be effective for HbA(1c) improvement in subjects with high L/A and low L/A. The average HbA(1c) improved from 9.2% +/- 0.9% to 8.0% +/- 1.2% (P = .0002) in 6 months after treatment with metformin. Our results indicate metformin to be effective for HbA(1c) improvement in subjects with a low L/A. In conclusion, we demonstrate that L/A is different between male and female subjects. The correlation of L/A and GIR by the euglycemic hyperinsulinemic clamp test suggests that L/A is a useful indicator for the choice of drug to treat diabetes mellitus.
Oda
Naohisa
N
Division of Endocrinology and Metabolism, Department of Internal Medicine, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan.
Imamura
Shigeo
S
Fujita
Takashi
T
Uchida
Yuka
Y
Inagaki
Kazumichi
K
Kakizawa
Hiroaki
H
Hayakawa
Nobuki
N
Suzuki
Atsushi
A
Takeda
Jun
J
Horikawa
Yukio
Y
Itoh
Mitsuyasu
M
D052242:Adiponectin / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy; D005260:Female; D015309:Glucose Clamp Technique; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007333:Insulin Resistance / Q000502:physiology*; D020738:Leptin / Q000097:blood*; D008297:Male; D008687:Metformin / Q000627:therapeutic use; D008875:Middle Aged; D000077205:Pioglitazone; D045162:Thiazolidinediones / Q000627:therapeutic use
D052242:Adiponectin; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D020738:Leptin; D008687:Metformin; D000077205:Pioglitazone; D045162:Thiazolidinediones