Hypotheses Concerning the Mechanism of Adenohypophyseal Hormone Release by Neurosecretory Material in Mammals
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Authors
Emerson, Marcia Brackney
Issue Date
1967
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Resolution of issue, as all the others discussed throughout this paper,
awaits further research. The necessity to investigate the the link that certainly
seemed to exist between the nervous and endocrine systems could not be denied.
Research has established with a great degree of certainty the embryology,
anatomy, and histology of the pituitary gland and the hypothalmus. The afferent
nervous and humoral pathways leading to the hypothalmus have been
fairly well established as has the release of the trophic hormones and their
subsequent action upon their target organs. The question of what activity
transpires in the hypothalamo-hypophysea1 system in the interval between
hypothalamic stimulation and hypophyseal response has yet to be answered.
Part of the enigma has been elucidated. Hypothalamic median eminence extracts
have yielded individual release factors which have been shown to actively
cause the release of their specific trophic hormones. The amino acid sequence
of one on these release factors has already been found in its entirty. The
others will probably be determined within the next two to three years of
research. But questions as to the composition and function of the populations
of vesicles and granules in hypothalmic nerve endings, or how the neurosecretory
release factors are liberated from the neuronal endings to the capillaries
will be answered only after much more research. Again experimental
evidence has, shown that an activity does occur. but does not explain how it
occurs. And the primary question still remains, How, by what mechanism,
does the ISM act on the adenohyposeal cells? On this issue the experimental
data are so new as to allow unrestrained hypothesizing. Hence a
genetic induction and repression and a neurosecretory release factor addition
model were proposed. Each is supported by small amounts of data and large
amounts of hopefully logical supposition. What remains is for research
to evaluate the adequacy of either of these hypotheses separately, or both
functioning together.
Description
v, 107 p.
Citation
Publisher
Kalamazoo College
License
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