Gender difference in growth hormone response in adults

Area of Science:

• Endocrinology
• Metabolic Medicine
• Bone Biology

Background:

• Growth hormone (GH) replacement therapy offers benefits for adults with GH deficiency.
• GH secretion and response to treatment can be influenced by sex steroids.
• Emerging evidence suggests a clinically significant gender difference in GH treatment response.

Purpose of the Study:

• To investigate gender-specific responses to recombinant human GH (rhGH) in adults with GH deficiency.
• To compare changes in insulin-like growth factor-I (IGF-I), body composition, and bone metabolism between men and women.

Main Methods:

• A 9-month placebo-controlled study involving 36 men and women with GH deficiency receiving a fixed rhGH dose per body surface area.
• Subsequent 24-month extension with rhGH dose adjusted to maintain target IGF-I levels.
• Assessment of IGF-I, body composition, bone turnover markers, and bone density (hip and lumbar spine).

Main Results:

• Initially, men showed significantly greater improvements in IGF-I, body composition, and bone metabolism markers compared to women.
• After dose adjustment, IGF-I and bone turnover normalized similarly in both sexes.
• Bone mineral density at the hip and lumbar spine increased significantly in men but not in women after 33 months.

Conclusions:

• Adults with GH deficiency exhibit gender-specific responses to rhGH therapy.
• Men demonstrate superior gains in bone density compared to women, irrespective of IGF-I normalization.
• Sex steroid differences may contribute to the observed gender disparity in rhGH treatment outcomes.