[Tyrosine phosphorylation and protein expression of insulin receptor substrate-2 in the adipose tissue from patients with polycystic ovary syndrome].
OBJECTIVE
To explore molecular mechanisms of insulin resistance of polycystic ovary syndrome (PCOS) by determining the tyrosine phosphorylation and protein expression of insulin receptor substrate-2 (IRS-2) in adipose tissue from patients with PCOS.


METHODS
Serum and subcutaneous adipose tissue samples from patients with PCOS with insulin resistance (n = 19), PCOS without insulin resistance (n = 17) and controls (n = 20) were collected. The expression of IRS-2 in adipose tissue was assessed by Western blot. Immunohistochemistry was used to detect the distribution of IRS-2 in adipose tissues of all patients. The tyrosine phosphorylation of IRS-2 was measured by immunoprecipitation and enhanced chemiluminescent immunoblotting technique.


RESULTS
(1) There was no significant difference of the protein expression of IRS-2 in PCOS with insulin resistance 1.15 +/- 0.26 compared to those in PCOS without insulin resistance 1.13 +/- 0.26 and control group 1.00 +/- 0.25 (P > 0.05); (2) The tyrosine phosphorylation of IRS-2 was significantly decreased in PCOS with insulin resistance 0.77 +/- 0.16 compared to that of PCOS without insulin resistance 0.91 +/- 0.25 and control groups 1.00 +/- 0.12 (P < 0.05). There was no significant difference between PCOS without insulin resistance and control groups (P > 0.05).


CONCLUSIONS
The decrease of tyrosine phosphorylation of IRS-2 in PCOS patients, which induces impairment of the insulin signal pathway, may be one of the mechanisms leading to insulin resistance.
Qiu
Hong-yu
HY
Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022.
Chu
Yong-li
YL
Li
Min
M
Sun
Yong-yu
YY
Li
Hong-fa
HF
D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D015153:Blotting, Western; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007150:Immunohistochemistry; D007328:Insulin / Q000097:blood; D055504:Insulin Receptor Substrate Proteins; D007333:Insulin Resistance; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011085:Polycystic Ovary Syndrome / Q000378:metabolism* / Q000503:physiopathology; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism*
D001786:Blood Glucose; C526297:IRS2 protein, human; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D014443:Tyrosine; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone