Olfactory bulb, elevated

Of significant interest are the most recent studies in rats that evaluate the thymus-reproductive and thymus-stress axes. Both in vitro administration of thymosin P4 into the medial basal hypothalamus and pituitary in chambers and in vivo administration into the cerebrovascular system have induced elevations of LH in media and serum, respectively (Rebar et al., 1981b Hall et al., 1983). Localization studies have demonstrated that the rat olfactory bulb has the highest concentration of thymosin 4, although it is also present in several other distinct sites (Hannappel et al., 1982). On the other hand, Toj did not influence levels of LH. Nevertheless, Ta is also present in the brain (Hall et al., 1982 Palaszynski et al., 1983), with its highest concentrations in the subcortical nuclei involved with both the autonomic and neuroendocrine system. These sites include both the pituitary gland and the hypothalamus. When injected intracranially, thymosin otj stimulated a rise in serum corticosterone in mice (Hall et al., 1982). The increase was rapid (<3 hours) and did not occur in experiments where the peptide was incubated with cultured adrenal fasciculata cells (Vahouny et al., 1983). 

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