Alterations in the sensitivity of serum insulin-like growth factor 1 and insulin-like growth factor binding protein-3 to octreotide in polycystic ovary syndrome

To determine if the somatostatin analog, octreotide, affects insulin and related peptides and, hence, androgen levels differently between polycystic ovary syndrome (PCOS) patients and controls. Prospective controlled trial. Reproductive endocrinology clinic of our medical center. Eleven women with PCOS and six matched ovulatory controls. Octreotide (100 μg) was administered subcutaneously in the midfollicular phase. Serum was obtained before and at 60, 120, 180, and 240 minutes after octreotide. Fasting insulin, insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3), T, androstenedione (A), and LH. In PCOS, baseline levels of T, A, LH, and fasting insulin were significantly higher than in controls. Pretreatment IGF-1 and IGFBP-3 levels were similar in PCOS and controls. Octreotide reduced fasting insulin levels significantly but to a similar degree in control and PCOS patients (77% and 90%, respectively). Both groups also experienced a significant decrease in LH levels after octreotide administration, but no significant changes were demonstrated in serum T or A. However, serum IGF-1 suppression in PCOS was greater (63% versus 8% in controls). Serum IGFBP-3 levels increased after octreotide administration in both groups with a larger increase (40%) occurring in the PCOS patients. These data suggest that women with PCOS may be more sensitive to the effects of octreotide in decreasing IGF-1 and increasing IGFBP-3. Although no significant changes could be demonstrated in ovarian androgens after a single dose, octreotide effectively reduced serum LH and insulin and, as such, may prove useful in treating some patients with PCOS.