Summary
Circulating levels of insulin and C-peptide in response to oral glucose administration
(75 g) were measured in 25 PCOS patients (13 were obese and 12 non-obese) without
acanthosis nigricans and in 12 non-obese normal cycling women of similar age.
Fasting levels of insulin and C-peptide as well as the sums of their levels in response
to glucose were significantly greater in PCO patients than in controls despite similar
glucose responses. Obese PCO patients had greater basal levels, maximum increments
and sums of insulin and C-peptide levels than non-obese PCO patients and controls.
PCO patients with increased basal total testosterone levels had significantly greater
mean fasting insulin levels (p < 0.005) than those with normal testosterone levels
but their responses to glucose were not significantly different.
Hyperprolactinaemic PCO patients had neither basal level nor sums of insulin and C-peptide
levels in response to glucose greater than normoprolactinaemic PCO patients.
In all PCO patients BMI correlated significantly with insulin (p < 0.05) and C-peptide
levels (p < 0.001). Total serum testosterone levels correlated significantly with
fasting levels and the sum of C-peptide levels in response to glucose. The correlations
of total serum testosterone levels with fasting and the sum of insulin levels in response
to glucose were also positive but not significant.
These results clearly indicate that in PCOS there is a significant degree of hyperinsulinaemia
which is mainly related to obesity.
Key words
Polycystic ovary syndrome (PCOS) - Hyperinsulinism - C-peptide - Obesity
