Show simple item record

dc.contributor.authorGleeson, Helena K
dc.contributor.authorShalet, Stephen M
dc.date.accessioned2009-08-05T16:13:24Z
dc.date.available2009-08-05T16:13:24Z
dc.date.issued2005-12
dc.identifier.citationGH responsiveness varies during the menstrual cycle. 2005, 153 (6):775-9 Eur. J. Endocrinol.en
dc.identifier.issn0804-4643
dc.identifier.pmid16322382
dc.identifier.doi10.1530/eje.1.02037
dc.identifier.urihttp://hdl.handle.net/10541/76409
dc.description.abstractOBJECTIVE: The GH-IGF-1 axis is affected by oestrogen. Both endogenous and exogenous oestrogen facilitates the central drive of pulsatile GH secretion. However, the effect on IGF-1 levels is more subtle, and a reduction in GH sensitivity has been proposed. The IGF generation test has confirmed reduced GH sensitivity with high doses of exogenous oestrogen. It is not known, however, whether fluctuant levels of endogenous oestrogen modify GH sensitivity. To investigate this further, women were challenged with the IGF-1 generation test at different stages of the menstrual cycle. METHODS: Nine women (age 38(6) years (mean (s.d.)) with regular menstrual cycles were recruited. An IGF-1 generation test, s.c. injection of 7 mg GH, was performed in the early-follicular (EF), periovulatory (PO) and midluteal (ML) phases. IGF-1, insulin-like growth factor binding protein (IGFBP)-3 and acid-labile subunit (ALS) levels were measured at baseline and 24 h after GH administration. RESULTS: Oestradiol levels were lower in the EF than PO or ML phases (32.6(7.8) vs 69.6(16.2) vs 66.6(23.6) pg/ml respectively (repeated measures ANOVA, P < 0.001)). Baseline IGF-1 was lower, but increment IGF-1 (peak minus baseline) was higher in the EF than PO or ML phases (baseline: 291.8(56.6) vs 335.0(55.2) vs 346.6(78.2) ng/ml (P = 0.008); increment IGF-1: 234.6(59.2) vs 194.7(37.8) vs 185.2(37.3) ng/ml (P = 0.008)). CONCLUSIONS: Increased endogenous oestrogen levels are associated with only a modestly elevated baseline IGF-1 from midcycle onward despite a previously reported twofold increase in GH secretion. In parallel with this apparent GH insensitivity, increased endogenous oestrogen levels are associated with reduction in GH sensitivity evidenced by reduction in increment IGF-1. This may have clinical implications for women with isolated GH deficiency with regular menstrual cycles on a fixed dose of GH. This possibility requires further study.
dc.language.isoenen
dc.subject.meshAdult
dc.subject.meshCarrier Proteins
dc.subject.meshEstradiol
dc.subject.meshFemale
dc.subject.meshFollicular Phase
dc.subject.meshGlycoproteins
dc.subject.meshHuman Growth Hormone
dc.subject.meshHumans
dc.subject.meshInsulin-Like Growth Factor Binding Protein 3
dc.subject.meshInsulin-Like Growth Factor I
dc.subject.meshLuteal Phase
dc.subject.meshMenstrual Cycle
dc.subject.meshOvulation
dc.subject.meshRecombinant Proteins
dc.titleGH responsiveness varies during the menstrual cycle.en
dc.typeArticleen
dc.contributor.departmentDepartment of Endocrinology, Christie Hospital, Wilmslow Road, Withington, Manchester M20 4BX, UK. Helena.Gleeson@christie-tr.nwest.nhs.uken
dc.identifier.journalEuropean Journal of Endocrinologyen
html.description.abstractOBJECTIVE: The GH-IGF-1 axis is affected by oestrogen. Both endogenous and exogenous oestrogen facilitates the central drive of pulsatile GH secretion. However, the effect on IGF-1 levels is more subtle, and a reduction in GH sensitivity has been proposed. The IGF generation test has confirmed reduced GH sensitivity with high doses of exogenous oestrogen. It is not known, however, whether fluctuant levels of endogenous oestrogen modify GH sensitivity. To investigate this further, women were challenged with the IGF-1 generation test at different stages of the menstrual cycle. METHODS: Nine women (age 38(6) years (mean (s.d.)) with regular menstrual cycles were recruited. An IGF-1 generation test, s.c. injection of 7 mg GH, was performed in the early-follicular (EF), periovulatory (PO) and midluteal (ML) phases. IGF-1, insulin-like growth factor binding protein (IGFBP)-3 and acid-labile subunit (ALS) levels were measured at baseline and 24 h after GH administration. RESULTS: Oestradiol levels were lower in the EF than PO or ML phases (32.6(7.8) vs 69.6(16.2) vs 66.6(23.6) pg/ml respectively (repeated measures ANOVA, P < 0.001)). Baseline IGF-1 was lower, but increment IGF-1 (peak minus baseline) was higher in the EF than PO or ML phases (baseline: 291.8(56.6) vs 335.0(55.2) vs 346.6(78.2) ng/ml (P = 0.008); increment IGF-1: 234.6(59.2) vs 194.7(37.8) vs 185.2(37.3) ng/ml (P = 0.008)). CONCLUSIONS: Increased endogenous oestrogen levels are associated with only a modestly elevated baseline IGF-1 from midcycle onward despite a previously reported twofold increase in GH secretion. In parallel with this apparent GH insensitivity, increased endogenous oestrogen levels are associated with reduction in GH sensitivity evidenced by reduction in increment IGF-1. This may have clinical implications for women with isolated GH deficiency with regular menstrual cycles on a fixed dose of GH. This possibility requires further study.


This item appears in the following Collection(s)

Show simple item record