The present studies were designed to determine if endogenous pancreatic islet cell monoamines such as serotonin, dopamine and norepinephrine play a physiological role in controlling insulin secretion. With an in vitro rabbit pancreas system, the effects of both serotonin and catecholamine antagonists on basal and stimulated insulin release were studied. Methysergide maleate (Sansert) potentiated both glucose and tolbutamide-stimulated insulin secretion, but alone it had no effect on insulin release. Studies in which exogenous monoamines were added to the incubations demonstrated that methysergide, purported to be a specific serotonin antagonist, blocked inhibition of insulin secretion by dopamine, 1-norepinephrine, 1-epinephrine and 1-isoproterenol. Methysergide differed in action from the alpha adrenergic blocking drug, phenoxybenzamine, for although the latter was a more potent blocker of the inhibitory action of exogenous catecholamines on insulin secretion, it did not potentiate glucose-stimulated insulin secretion. Glucose-mediated insulin secretion was also potentiated by the serotonin antagonists, cinanserin and cyproheptadine. Exogenous serotonin (4 x 10" 3 M) had only a weak action in inhibiting insulin secretion from rabbit pancreas. Methysergide (1 x 10" 4 M) failed to block this inhibitory action. It is suggested that (1) serotonin antagonists are blocking the inhibitory action of an intracellular compartmentalized serotonin pool, (2) some other endogenous indoleamine is the inhibitory substance that is being blocked by the serotonin antagonists, or (3) the three ser.otonin antagonists are influencing glucose-mediated insulin release through some unknown mechanism that has nothing to do with serotonin. DIABETES 21: 779-88, July, 1972. Pharmacological doses of biogenic amines such as epinephrine, 1 ' 2 norepinephrine, 3 dopamine 4 and serotonin 5 ' 7 are potent inhibitors of pancreatic insulin secretion. Because such agents must be used in supraphysiologic quantities to exert this effect, many investigators have questioned the physiological significance of endo-
The efficacy of lysostaphin nasal spray and Neosporin ointment (Burroughs Weilcome & Co.) in altering nasal carriage of Staphylococcus aureus was studied with persistent carriers in an institution for mentally retarded children and adults. Treatment for 5 days with either agent significantly reduced carriage rates. This effect persisted through the 5th day after therapy with lysostaphin but not with Neosporin. By the 11th day after therapy, carriage rates in the treatment and control groups were not significantly different. Except for a single immediate wheal and flair skin test reaction, no other evidence of adverse reactions to topical lysostaphin was detected. No consistent changes in hemagglutination-inhibition titers to lysostaphin were observed after therapy. Lysostaphin appears to be slightly more effective than conventional topical antimicrobial therapy in reducing nasal carriage of staphylococci in this rigorously defined population of persistent carriers.
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