STRUCTURE OF CALVARIA AFTER GASTRECTOMY - A EXPERIMENTAL-STUDY IN THERAT

Background: Gastrectomy induces bone loss, suggesting that the stomach is important for calcium homeostasis. In this study we examined the e ffects of gastrectomy, with or without CaCl2 supplementation, on the s tructure of the calvaria of the rat. Methods: The calvaria were dissec ted out and transilluminated, and the calvaria thickness was measured before (micrometer) and after fixation and sectioning (microscopy). Se ctions of the skull were analysed planimetrically for bone tissue area , using computer-assisted image analysis. Results: The time course of the gastrectomy-produced bone loss was studied. After 4 weeks the rema ining bone represented about 70% of that in control rats, and after 8 weeks the value was 50%. The thickness of the calvaria was lower in ga strectomized rats than in sham-operated controls. Bone marrow and samp les from liver and spleen were examined; no differences were found bet ween experimental and control groups. Daily ingestion of 100 mg CaCl2 . 2H(2)O did not prevent the bone loss. Conclusions: It is unlikely th at the gastrectomy-produced bone loss reflects calcium deficiency. The results rather support the view that the stomach is important for cal cium homeostasis through another mechanism, perhaps involving a hypoth etical gastric hormone.