Influence of gestagens used in hormonal replacement therapy on the secretion of GIP, GLP-1 in postmenopausal women

Aim of the study: To evaluate GIP and GLP-1 secretion in postmenopausal women on the HRT in relation to gestagen used.

Material and method: 105 postmenopausal women (mean age 59.0 ±3.4 years) were included in the study. Group I (n = 32) consisted of women treated with oral dydrogesterone and transdermal 17-b- estradiol. Group II

(n = 30) was treated with 17-b-estradiol and dydrogesterone orally. Group III (n = 15) received 17-b-estradiol transdermally and medroxyprogesterone orally. Women from group IV (n = 10) received 17-b-estradiol and noretisterone orally. Blood was taken twice – before and 60 min. after the meal - to the chilled tubes with EDTA and aprotinin. Such a protocol was used before the HRT began and in the 6th month of the HRT.

Results: The HRT resulted in diminished plasma concentration of GIP and GLP-1 in both group I and II – before and after the meal (p < 0.05). In group III the same tendency in GIP levels was observed but the differences were not statistically significant. The GLP-1 concentrations were not affected by HRT, as well as GIP and GLP-1 levels in group IV.

Conclusion: The plasma concentration of incretins (GIP and GLP-1) depends on the route of HRT delivery and on the kind of gestagen used.