Effects of two oral contraceptives on plasma levels of insulin-like growth factor I (IGF-I) and growth hormone (hGH).
In 18 healthy women, the effect of two oral contraceptives (OCs) on insulin-like growth factor (IGF-I) and its binding protein-3 (IGFBP-3) and growth hormone (hGH) plasma level were studied before and after intake of either of two OC formulations over 21 days, one containing 2 mg dienogest and 0.03 mg ethinylestradiol (group A) and the other 0.125 mg levonorgestrel and 0.03 mg ethinylestradiol (group B). There was a reduction of the mean IGF-I concentration of 30% (p = 0.008) in the women receiving dienogest-containing pills and 12% (p = 0.006) in women taking the levonogestrel-containing preparation. This difference between drug groups was statistically significant (p = 0.002). A correlation between the control values and the basal-treatment difference (r = 0.945; p = 0.000) was observed only in women of group A. Between basal and treatment cycles the mean plasma levels of hGH remained unchanged in both groups tested, but the 23.5-h integrated mean hGH plasma concentrations (AUC(0-23.5h)) were significantly elevated by 36% (p = 0.016) in comparison to basal values before treatment only in women receiving the levonorgestrel-containing pills. Also, in the women who received the dienogest-containing preparation, the changes of integrated mean plasma level were inversely associated with the control values (r = -0.723; p = 0.025). Neither in group A nor in group B was the mean plasma level of IGFB-3 changed.


CONCLUSIONS
the results of the present analysis indicate that hormonal contraceptives can modulate the GH and IGF-I-axis in the reproductive age. Probably the androgenic progestogen levonorgestrel (0.125 mg/day) opposes the estrogen-induced action. In the women who took the dienogest-containing formulations (anti-androgenic progestogen-group A), the extent of individual changes (hGh and IGF-I) depends on the basal level prior to pill intake. Further studies, especially of long-term intake of OCs, are necessary to confirm these results and to assess the practical relevance for possible effects on connective tissue and bone.
Balogh
A
A
Department of Clinical Pharmacology, Friedrich Schiller University of Jena, Jena, Germany. annegret.balogh@med.uni.jena.de
Kauf
E
E
Vollanth
R
R
Gräser
G
G
Klinger
G
G
Oettel
M
M
D003271:Contraceptive Agents, Female / Q000494:pharmacology*; D003277:Contraceptives, Oral, Combined / Q000494:pharmacology; D004997:Ethinyl Estradiol / Q000494:pharmacology; D005260:Female; D019382:Human Growth Hormone / Q000097:blood* / Q000187:drug effects; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood / Q000187:drug effects; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000187:drug effects; D016912:Levonorgestrel / Q000494:pharmacology; D016014:Linear Models; D009277:Nandrolone / Q000031:analogs & derivatives* / Q000494:pharmacology; D013997:Time Factors
D003271:Contraceptive Agents, Female; D003277:Contraceptives, Oral, Combined; D018972:Insulin-Like Growth Factor Binding Protein 3; D019382:Human Growth Hormone; D004997:Ethinyl Estradiol; C023635:dienogest; D016912:Levonorgestrel; D007334:Insulin-Like Growth Factor I; D009277:Nandrolone