| Summary: | 碩士 === 國立清華大學 === 生命科學研究所 === 84 === It is now well established that nitric oxide (NO) is a
major inter- and intracellular neurotransmitter in
the brain and peripheral nervous system. NO is formed from
L-arginine by the enzyme NO synthase (NOS).
Remarkable conservation of neuronal NOS has been noted
between verterbrates and inverterbrates. Recently, NOS has
also been identified in discrete subpopulations of
anterior pituitary cells and NO may exert an inhibitory
effect on release of luteinizing hormone and growth
hormone. While there are ev idence showing production of NO
from insect nervous system, nothing is known about the
cellular localization of NOS in insect endocrine system.
Insect corpora allate (CA) produce juvenile hormone
(JH) and are considered the analogue of the anterior
pituitary gland of verterbrates. While the CA have been
shown to be the release site for several neuropeptides from
brain neurosecretory cells, it is generally believed
that JH is the only product synthesized and released from
corpus allatum cells involving in the regulation of insect
growth, metamorphosis and reproduction. We have now
demonstrated that all corpus allatum cells contain a
constitutive NOS which synthesize and release NO. The NOS is
calcium dependent and inhibited by brain neurons terminating
in the CA.
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