The importance of the hormone replacement therapy (HRT) in the quality of life at the postmenopause is unquestionable. However not all the effects determinated by its use are well established yet. This study has the aim to evaluate the influence of the HRT on serum levels of the growth hormone (GH), insulin-like growth factor I (IGF-I), insulin-like growth factor binding protein 3 (IGFBP-3), glucose and insulin. We performed a controlled, prospective, longitudinal and comparative clinical trial, in which 53 natural or surgical postmenopausal women were submitted or not to a continuous HRT, during a 6 months period, with conjugated estrogens (CE-0.625mg/d) associated or not to the medroxiprogesterone acetate (MPA-2.5mg/d), by the oral route. The participants were subdivided in 3 groups: Group CE + MPA > composed by 20 women with uterus, who utilized CE and MPA; Group CE > composed by 20 hysterectomized women, who used CE; Group C > formed by 13 women, without HRT. Basal levels of GH, IGF-I and IGFBP-3 were measured in the beginning and at the end of the study. We have also performed a 2-hour oral glucose tolerance test (OGTT), with determination of glucose and insulin levels; area under curve (AUC) of glucose and insulin and insulin resistance index (IRI). The HRT use decrease the IGF-I levels in CE + MPA (p= 0.01) and CE (p= 0.0007), without change in the IGFBP-3 levels. The GH levels increased during the use of the HRT (EC + AMP: p= 0.004 e EC: p= 0.0003), however the serum concentrations of IGF-I and IGFBP-3 did not seem to be good markers of the circadian secretion of GH. At 6 months, it was noticed a negative correlation of the IGF-I with the AUC of glucose in the three groups (CE + MPA: r= -0.42, p= 0.06; CE: r= -0.58, p= 0.007 and C: r= -0.64, p= 0.01). The IGFBP-3 and the AUC of glucose showed a significant negative correlation in the group CE (r= -0.45, p= 0.04) and a tendency in CE + MPA (r= -0.42, p= 0.06). The association of MPA determined the appearance of IGT in 30% of the patients from the group EC + AMP (n= 6). Our results suggested an interaction between the carbohydrate metabolism with the IGF-I and IGFBP-3. The effects caused by the prolonged use of continuous HRT in the regulation of GH, IGF-I and IGFBP-3 still require elucidation.
Growth hormone (GH); Insulin-like growth factor I (IGF-I); Insulin-like growth factor binding protein 3 (IGFBP-3); Hormone replacement therapy (HRT)
