Highly selective vagotomy in the rat: effects on bone and mineral metabolism

Highly selective vagotomy (HSV) or sham operation was performed in male rats. Fifteen weeks later bone mineralization, fractional intestinal absorption and balance, urinary excretion, and serum levels of calcium, magnesium and phosphorus, together with serum gastrin, parathyroid hormone, calcitonin, vitamin D metabolites, osteocalcin, isoenzymes of alkaline phosphatase, and the urinary excretion of cyclic AMP and hydroxyproline were assessed. HSV induced chronic hypergastrinemia and enhanced the weight of the fundus, antrum, and pancreas. Body weight, food intake, intestinal absorption, mineral balance, and bone mineralization were unaffected by HSV, whereas serum parathyroid hormone levels and urinary hydroxyproline excretion were increased. It is concluded that in the rat 1) HSV has a trophic effect on gastric and extragastric tissues; 2) gastric acid production is not a major determinant of intestinal calcium absorption; and 3) normal bone mass in the presence of signs of hyperparathyroidism indicates an intrinsic capacity of HSV to interfere with calcium metabolism, probably via hypergastrinemia, gastrin being an element of the gastro-parathyroid axis. Our present findings underscore the fact that osteopenia after HSV in man may be a rare finding, but it cannot be ruled out that bone disease found after partial or total gastrectomy may be due in part to concomitant vagotomy.