Men with acromegaly need higher doses of octreotide than women

To investigate the effect of gender on the response of GH to short-acting octreotide in patients with acromegaly, and on the GH and IGF-1 levels during long-term treatment with a slow-release formulation of octreotide.

Twenty-one men (mean age 54 years; range 26-78) and 15 women (mean age 54 years; range 22-74) with acromegaly were treated with subcutaneous injections of 100 microg short-acting octreotide twice daily. Serum samples for GH were taken before start of treatment, in the morning prior to the injection, and 1, 3, 5 and 7 h after the injection. Thirteen men (mean age 56 years; range 34-78) and 12 women (mean age 64 years; range 28-81) with acromegaly were switched from ongoing treatment with short-acting octreotide to injections of the slow-release formulation. A 4-h GH-profile and morning IGF-1 were taken at start and after 3, 9, 15 and 21 months of treatment.

Subcutaneous injections of 100 microg octreotide reduced the mean level of GH during a 7-h period to a similar extent in men and women compared to the GH levels prior to the injections. During long-term treatment with similar doses of the depot formulation of octreotide, the mean IGF-1 level remained significantly higher in the men than in the women, whereas there were no differences in the mean GH levels between the two groups.

The responses to short- and long-acting octreotide illustrate an effect of gender, due to different sensitivity to GH in the periphery. Furthermore, the results show that in the treatment of acromegaly, men will need higher doses of octreotide than women to normalize IGF-1.