Inhibits the secretion of pituitary hormones, including that of growth hormone/somatotropin (GH1), PRL, ACTH, luteinizing hormone (LH) and TSH. Also impairs ghrelin- and GnRH-stimulated secretion of GH1 and LH; the inhibition of ghrelin-stimulated secretion of GH1 can be further increased by neuronostatin. May enhance low-glucose-induced glucagon release by pancreatic alpha cells (PubMed:24735892). This effect may be mediated by binding to GPR107 and PKA activation (PubMed:26561648). May regulate cardiac contractile function (PubMed:22170057). May compromise cardiomyocyte viability (PubMed:22170057). In the central nervous system, may impair memory retention and may affect hippocampal excitability (PubMed:21978882). May also have anxiolytic and anorexigenic effects (PubMed:18753129, PubMed:21978882). May play a role in arterial pressure regulation (PubMed:18753129, PubMed:21978882). May inhibit basal, but not ghrelin- or GnRH-stimulated secretion of GH1 or LH, but does not affect the release of other pituitary hormones, including PRL, ACTH, FSH or TSH (By similarity). Potentiates inhibitory action of somatostatin on ghrelin-stimulated secretion of GH1, but not that on GnRH-stimulated secretion of LH (By similarity). Somatostatin is detected in neurons throughout the brain, including in the lateral septum, nucleus accumbens, amygdaloid complex, hypothalamic periventricular nucleus, hippocampus, cortex, cerebellum and several brainstem nuclei (at protein level) (PubMed:20056135). Neuronostatin is widely expressed with highest levels in pleen and pancreas, followed by cerebrum and hypothalamus (at protein level) (PubMed:18753129, PubMed:26561648). Neuronostatin plasma levels are higher in fasted, as compared to fed animals (PubMed:26561648). In the brain, neuronostatin is mainly present in the hypothalamic periventricular nucleus and median eminence (at protein level) (PubMed:20056135). C-terminal amidation of the neuronostatin peptide is required for its biological activity, including for the regulation of mean arterial pressure. Belongs to the somatostatin family.