RESUMO
BACKGROUND: Gastrin has a wide variety of functions on the digestive system including the regulation of gastric acid secretion, being a growth factor for the non antral gastric mucosa and the stimulation of mucosal proliferation in the large and small intestines. Animals studies showed that various diseases of the digestive system have better clinical evolution in the presence of estrogens as is the case of peptic ulcers, now little is known in humans about this phenomenon. OBJECTIVE: To evaluate the response of gastrin after an oral calcium load in normal and postmenopausal women without hormone replacement therapy. PATIENTS AND METHODS: We studied 10 healthy women with mean age 25.3 +/- 1.79 yr (range: 23-28 yr) and 7 postmenopausal women without previous treatment and a mean age 56.5 +/- 6.4 yr (range: 50-70 yr). A permeable vein with physiologic solution was obtained in order to maintain a permeable vein in the antecubital fossa to obtain blood samples for the determination of gastrin. Before an oral administration of 1 g of calcium baseline samples were taken at time 0 and thereafter on 30, 60, 90, 120, 150, and 180 minutes. Gastrin levels were determined by RIA using CIS Bio-International commercial kits. RESULTS: Basal gastrin levels were x: 72.54 +/- 15.9 pg/mLK in normal women and x: 61.1 +/- 39.62 in postmenopausal women. Basal gonadotrophins were x: 62.1 +/- 26 and x: 32.9 +/- 7.3 for FSH and LH respectively and estradiol level of x: 13.9 +/- 4.2 pg/mL. Normal volunteers had a peak secretion of x: 173.4 +/- 15 pg/mL at 90 minutes and in postmenopausal women a peak of x: 66.2 +/- 50 at 60 minutes. Comparing the magnitude of the response between the healthy volunteers and the postmenopausal women at 90 and 120 minutes the statistical significance was a (p < 0.005) and (p < 0.001), respectively. CONCLUSIONS: These results demonstrate the lack of response of gastrin levels to the calcium stimulus in postmenopausal women probably due to the lack of hormone replacement therapy. Further studies are needed to best understand the role of sexual hormones on the synthesis and secretion of gastrin in the digestive system especially the role of the estrogens.