Spermine induces precocious development of the spleen in mice

Spermine is a low molecular weight polyamine involved in the postnatal maturation of the gut. When it is
administered orally to suckling rats, it induces maturation of the intestinal tract (liver, pancreas and small
intestine). Here we show that this polyamine is able to induce precocious intestinal and splenic development in
suckling mice. In fact, in 15-day-old mice which had received spermine orally twice daily for 3 days we observed
an increase in the ratio of white pulp surface to total spleen surface in comparison with untreated mice. The two
macrophage subsets of the marginal zone and the B-cell population were more developed and reached the
development level of 5- or 10-week-old mice. The proliferation rate of B-cells was increased by spermine
administration to pups. These observations suggest that spermine might play a role in immune system
development; further investigation of its effects are intended, namely the evaluation of its capacity to enhance
defence during the neonatal period.