Indices of insulin sensitivity, beta cell function and serum proinsulin levels in the polycystic ovary syndrome.
BACKGROUND
The study aim was to investigate the relationship between insulin resistance (IR), beta-cell function (betaF), hyperandrogenism and proinsulin levels during an oral glucose tolerance test (OGTT) in women with polycystic ovary syndrome (PCOS).


METHODS
One hundred and twenty-six selected women were classified as follows: PCOS, BMI > 25 kg/m2 (n = 39); PCOS, BMI < 25 kg/m2 (n = 54); controls, BMI > 25 kg/m2 (n = 14); controls, BMI < 25 kg/m2 (n = 19). Blood samples were collected between the third and sixth day of a spontaneous menstrual cycle, at 9:00 a.m., after an overnight fast. Serum levels of FSH, LH, PRL, 17alpha-OH-progesterone, SHBG, testosterone, delta4-androstenedione, insulin, proinsulin and glucose were measured. A 75 g OGTT was performed, and concentrations of glucose, insulin and proinsulin were also measured at t = 30, 60, 90, and 120 min.


RESULTS
The markers of insulin secretion and the AUC for proinsulin were higher in obese and overweight women and in women with PCOS, respectively. The AUC for proinsulin was positively correlated with markers of IR, betaF and androgen levels. An inverse relationship between PI/I values and indices of IR and betaF was observed.


CONCLUSIONS
Increased proinsulin levels reflect, most probably, insulin resistance, which is the key disorder in PCOS-associated metabolic abnormalities. Beta-cell function, pre-proinsulin mRNA processing and proinsulin conversion to insulin could be initially increased as a result of IR. An interaction between circulating proinsulin and androgen biosynthesis or action might also exist.
Panidis
Dimitrios
D
Division of Endocrinology and Human Reproduction, Second Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Thessaloniki, Greece. argic@med.auth.gr
Macut
Djuro
D
Farmakiotis
Dimitrios
D
Rousso
David
D
Kourtis
Anargyros
A
Katsikis
Ilias
I
Spanos
Nikolaos
N
Petakov
Milan
M
Bjekic
Jelica
J
Damjanovic
Svetozar
S
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D000735:Androstenedione / Q000097:blood; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D005260:Female; D006728:Hormones / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D009765:Obesity / Q000097:blood / Q000209:etiology; D050177:Overweight / Q000097:blood / Q000209:etiology; D011085:Polycystic Ovary Syndrome / Q000097:blood* / Q000150:complications / Q000378:metabolism; D011247:Pregnancy; D011384:Proinsulin / Q000097:blood*; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013254:Steroid 17-alpha-Hydroxylase / Q000097:blood; D013739:Testosterone / Q000097:blood
D015415:Biomarkers; D001786:Blood Glucose; D006728:Hormones; D007328:Insulin; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D000735:Androstenedione; D011384:Proinsulin; D013254:Steroid 17-alpha-Hydroxylase; C022445:progesterone 17-alpha-hydroxylase