Hypothalamic histamine, growth rate, plasma prolactin and growth hormone levels in rats with long-term portacaval anastomosis

Objective and Design: Histamine can modulate feeding behaviour and hormone release, therefore we examined the hypothalamic histamine system, the growt h 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 r ats 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, prol actin and growth hormone by RIA. Student's t-test was used to compare the g roups. Results: Six months after surgery, the PCA rats exhibited marked growth ret ardation (weight gain of 20 g vs. 140 g for the sham rats; p < 0.001), incr eased plasma levels of prolactin (9.7 +/- 2.4 vs. 3.6 +/- 0.6; p < 0.01) an d 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 hypotha lamus may be involved in the development of growth retardation and in the e nhanced basal secretion of prolactin in male rats with long-term PCA.