Abstract
Isolated islets of Langerhans of the rat were incubated for one hour in the presence
of 16 mM glucose. The effect of L-dopa, α-methyl-L-dopa and L-tyrosine on insulin
release was studied. L-dopa (2.5 x 10-5M) and α-methyl-L-dopa (10-4 M) each significantly inhibited insulin release. At this dose, the combination of
the two compounds was significantly more inhibitory than either compound alone. L-tyrosine
(10-4 M) did not affect insulin secretion.
Key words
Islets of Langerhans - Insulin Secretion - L-Dopa - α-Methyl-L-Dopa - L-Tyrosine
1 This study was supported by U.S.P.H.S. Grants AM-05078 and AM-02001, National Institute
of Arthritis and Metabolic Diseases
2 Past address: LCDR A.A. Rossini, MC, USNR, Charleston Naval Hospital, Charleston,
South Carolina, U.S.A.
Present address: Elliott P. Joslin Research Laboratory, Harvard Medical School, Boston,
Mass., U.S.A.
3 APUD = amine precursor uptake-decarboxylation
