A Rat Hypothalamic Extract Enhances Insulin Secretion in Vitro

Fractions from a partially purified ventrolateral hypothalamic (VLH) extract stimulate insulin (IRI) secretion when infused into isolated perfused rat pancreases. At a low glucose concentration (5 mM) in the perfusion medium, infusion of the VLH extract significantly increased insulin output when compared to controls infused with a cerebellar cortex extract. (IRI output with cerebellar cortex: 13.5 ± 0.81; with VLH extracts: 40.9 ± 9.4 ng/5 min, P < 0.05). At a high glucose concentration (10 mM) in the perfusion medium, IRI secretion evoked by glucose was further augmented by the simultaneous infusion of the VLH extract (IRI output with glucose: 325.6 ± 25.8; glucose + VLH extract: 448.1 ± 33.0 ng/20 min, P < 0.02). When pancreases were perfused with a solution containing 20 different amino acids [(AA) 6.6 mM final concentration] IRI secretion elicited by the AA was similarly augmented by the presence of the VLH extract (IRI output with AA: 101.8 ± 14.9; AA + VLH extract: 179.8 ± 21.9, P < 0.02). However,...