On the Mechanisms of Action of Hormones on Cells
RACHMIEL LEVINE
Department of Metabolic and Endocrine Research, Medical Research Institute,
Michael Reese Hospital, Chicago, Illinois
Page
I. Introduction
185
II. Insulin
187
III. Adrenaline
202
IV. Thyroid Hormones
204
V. Estrogens and Progesterone
208
VI. General Considerations
209
References
210
I. INTRODUCTION
This essay requires that an explanation be given, as much for what
it is not going to discuss, as for those aspects which will be brought
forth. The actual mechanism of action of any of the hormones is at
present unknown, but as if through a glass—dimly—a few strokes of the
outline of the picture are appearing. The time is therefore opportune
to analyze the attempts that have been made to get at the problem, and
above all to define as precisely as possible the goals of research in
this area.
It would seem desirable to distinguish clearly between the terms
"effect," "function," and "action" of a hormone, even though in the
biological literature these have often been used as if they were synonyms.
Of the three terms, "effect" is the most neutral, the least charged with
value judgment. It denotes the experimental observation of a change in
some measurement which follows the introduction of a hormone into
the organism as a whole or a portion thereof (organ, tissue, cell suspension, homogenate, or enzyme extract). All such observed effects are at
first equally valuable in shaping our understanding of the biology of the
hormone. The various effects are discontinuous points lying in one
plane. The further accumulation of data leads in time to the classification of certain effects as subsidiary, derived phenomena and thus a more
or less pyramidal ordering is obtained—a hierarchical system. The tip
of the pyramid, i.e., the effect(s) from which all others may be logically
and experimentally deduced, should be called the action of the hormone.
The goal is to be able to describe this primary effect or action in physical
or chemical terms, on the molecular level. However, since our knowl185
RACHMIEL LEVINE
Department of Metabolic and Endocrine Research, Medical Research Institute,
Michael Reese Hospital, Chicago, Illinois
Page
I. Introduction
185
II. Insulin
187
III. Adrenaline
202
IV. Thyroid Hormones
204
V. Estrogens and Progesterone
208
VI. General Considerations
209
References
210
I. INTRODUCTION
This essay requires that an explanation be given, as much for what
it is not going to discuss, as for those aspects which will be brought
forth. The actual mechanism of action of any of the hormones is at
present unknown, but as if through a glass—dimly—a few strokes of the
outline of the picture are appearing. The time is therefore opportune
to analyze the attempts that have been made to get at the problem, and
above all to define as precisely as possible the goals of research in
this area.
It would seem desirable to distinguish clearly between the terms
"effect," "function," and "action" of a hormone, even though in the
biological literature these have often been used as if they were synonyms.
Of the three terms, "effect" is the most neutral, the least charged with
value judgment. It denotes the experimental observation of a change in
some measurement which follows the introduction of a hormone into
the organism as a whole or a portion thereof (organ, tissue, cell suspension, homogenate, or enzyme extract). All such observed effects are at
first equally valuable in shaping our understanding of the biology of the
hormone. The various effects are discontinuous points lying in one
plane. The further accumulation of data leads in time to the classification of certain effects as subsidiary, derived phenomena and thus a more
or less pyramidal ordering is obtained—a hierarchical system. The tip
of the pyramid, i.e., the effect(s) from which all others may be logically
and experimentally deduced, should be called the action of the hormone.
The goal is to be able to describe this primary effect or action in physical
or chemical terms, on the molecular level. However, since our knowl185