Effects of short-term administration of growth hormone in healthy young men, women, and women taking oral contraceptives

Objective. Effects of short-term administration of growth hormone (GH) with respect to gender and oral contraceptives (OCs) were investigated in healt hy young adults. Design. Open, prospective 2-week study. Setting. Clinical research centre, university hospital. Subjects. Three groups of healthy young adults were included: six men, six women with normal menstrual cycles, and six women taking OCs. Interventions. The subjects were given recombinant human GH subcutaneously for 2 weeks: 1 U m(-2) body surface daily during the first week, and 3 U m( -2) daily during the second week. Main outcome measures. Serum samples were drawn in the morning after overni ght fasting on days 0, 3, 7, 10 and 14, and were analysed for GH, insulin-l ike growth factor 1 (IGF-1), insulin, testosterone, sex hormone-binding glo bulin (SHBG), lipids and markers of bone metabolism. Second-void morning ur ine was analysed for deoxypyridinoline (Dpyr). Results. During administration of GH, serum IGF-1 increased in the men and in the women without OCs (86 and 52%, respectively). In the OC women, IGF-1 did not change significantly. Serum insulin increased in all three groups, with the largest change (122%) in the men and the smallest (47%) in the OC women. Blood glucose was unchanged. Total cholesterol, low-density lipopro tein (LDL) cholesterol and the LDL/high-density lipoprotein cholesterol rat io were reduced in the men only. Biochemical markers of bone resorption (se rum procollagen type I, urinary Dpyr) increased in the men, and markers of bone formation (serum osteocalcin and telopeptide of collagen type I) incre ased in the men as well as in the women not taking OCs. The testosterone/SH BG ratio increased in the men on account of a reduction in SHBG. Conclusion. The response to short-term administration of GH differed in the three groups, with the largest effect in the men and the smallest in the O C women. The inhibitory influence of contraceptives underlines the role of sex steroids in modulating the susceptibility to GH.