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.

Objective: 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.

Design: Prospective controlled trial.

Setting: Reproductive endocrinology clinic of our medical center.

Patients: Eleven women with PCOS and six matched ovulatory controls.

Interventions: Octreotide (100 micrograms) was administered subcutaneously in the midfollicular phase. Serum was obtained before and at 60, 120, 180, and 240 minutes after octreotide.

Main Outcome Measures: Fasting insulin, insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3), T, androstenedione (A), and LH.

Results: 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.

Conclusions: 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.