Objective and design: Histamine can modulate feeding behaviour and hormone release; therefore we examined the hypothalamic histamine system, the growth pattern and the serum levels of prolactin and growth hormone in rats with portacaval anastomosis (PCA).
Material: The growth rate of 30 PCA- and 30 sham-operated male Han:Wistar rats was monitored for 6 months. Thirteen sham and 9 PCA rats were used for biochemical studies.
Methods: Histamine was assayed by HPLC, tele-methylhistamine by GC-MS, prolactin and growth hormone by RIA. Student's t-test was used to compare the groups.
Results: Six months after surgery, the PCA rats exhibited marked growth retardation (weight gain of 20 g vs. 140 g for the sham rats; p < 0.001), increased plasma levels of prolactin (9.7 +/- 2.4 vs. 3.6 +/- 0.6; p<0.01) and unaltered growth hormone levels (6.2 +/- 0.5 vs. 8.1 +/- 1.0). A six-fold elevation of histamine concentration (29.5 +/- 3.9 vs. 4.8 +/- 0.4; p<0.001) and a two-fold increase of tele-methylhistamine levels (1.8 +/- 0.1 vs. 0.8 +/- 0.02; p<0.001) were found in hypothalamus.
Conclusion: We suggest that increased histaminergic activity in the hypothalamus may be involved in the development of growth retardation and in the enhanced basal secretion of prolactin in male rats with long-term PCA.