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BIOCHEMICAL SOCIETY TRANSACTIONS
Lagnado, J. R., Lyons,C. & Wickremasinghe, G. (1971) FEBSLett. 15,254-258
Matus, A. I., de Petris, S. & Raff, M. C. (1973) Nature (London)New Biol. 244,278-280
Weisenberg, R. C., Borisy, G. G. &Taylor,E. W. (1968)Biochemistry 7,4466-4479
Amine-Dependent Synthesis of Peptides and Peptido-Amines
in Nervous Tissue
KL. REICHELT, P. D. EDMINSON and E. KVAMME
Department of Neurochemistry, The University Psychiatric Clinic, Vinderen, Oslo, 3,
Norway
The addition of amines such as histamine, dopamine (3,4-dihydroxyphenethylamine)
and 5-hydroxytryptaminecauses a rapid decrease in the concentration of acetylaspartate
in brain tissue slices (Reichelt et al., 1971).After inhibition of monoamine oxidaseactivity
in homogenates of cortical tissue, the same amines can induce a non-ribosomal synthesis
of peptides which is dependent on ATP (Reichelt & Kvamme, 1973). The amines are
apparently incorporated into both peptido-amines and acetylaspartate peptides, and the
nature of the specific peptides formed is dependent on the type of amino acids present
(at a concentraction of 0 . 5 m ~ ) and
,
to a lesser extent, partially on the type of amine
added (Reichelt & Edminson, 1974). Putative neurotransmitters like y-aminobutyric
acid, taurine, glycine and glutamic acid are incorporated into these peptides.
Reichelt, K. L. & Edminson, P. D. (1974) FEBS Lett. in the press
Reichelt, K. L. & Kvamme, E. (1973)J. Neurochem. 21,849-859
Reichelt, K. L., Wedege, E. & Kvamme, E. (1971) J. Neurochem. 18,2129-2136
Investigations of the Self-potentiating Effect of LuteinizingHormone-Releasing Hormone on Rat Pituitaries in vitro
JAMES A. EDWARDSON* and DAVID GILBERT?
*Department of Biochemistry, Imperial College, London S W7 4AZ, U.K. and
t Department of Biophysics and Biochemistry, Wellcome Research Laboratories,
Beckenham BR3 3BS, Kent, U.K.
It has been reported that when perifused anterior pituitary glands of di-oestrous female
rats were stimulated intermittently with luteinizing-hormone-releasinghormone
(Matsuo et al., 1971) a progressively increasing series of peaks of luteinizing-hormone
secretion resulted even when the secretion was allowed to return to baseline between
stimuli (Gilbert & Edwardson, 1974). Further studies using the same general procedure
have defined some properties of this phenomenon.
When the interval between stimuli(long of luteinizing-hormone-releasinghormone/ml
for 5min; flow rate 0.2ml/min) was 1h, potentiation occurred in the second and subsequent responses, but when the interval was 0.5h the first two or three responses were
similar in magnitude although there was a progressive increase in subsequent responses.
When the interval between stimuli was 1.5h little or no potentiation was observed. Continuous stimulation with luteinizing-hormone-releasinghormone (10ng/ml)produced an
initial rapid increase in luteinizing-hormone secretion during the first 20min followed by
a gradual further increase during the subsequent hour, after which the rate of secretion
remained constant. The acute response to a high concentration of K+ for 5min (1cKhnM
with adjustment of Na+ to maintain osmolarity) was similar to that to luteinizing-hormone-releasing hormone (10ng/ml) but repeated stimulation with this concentration of
K+ at intervals of 1h produced a series of equal responses.
Treatment of the glands with cycloheximide(5 or 250,ug/ml) for 1h before and during
a series of stimuli with luteinizing-hormone-releasing
hormone (lOng/ml) at intervals of
1975