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JAMES K. GRANT
different organisms. Zabin isolated C
14 -lycopene from ripening tomatoes
injected several days before with C
14 -acetate. The distribution of C
14
observed during degradation of the lycopene indicated that the carotenoid may be formed from identical isoprenoid units but failed to
show how the units are built up from acetate in the tomato. Later the
same author reported the incorporation of significant amounts of labeled
mevalonic acid into lycopene. Obviously more work is required here to
confirm the origin of the carbon atoms in the lycopene arid that the
biosynthesis of this substance is indeed different.
B. STEROID HORMONE BIOSYNTHESIS
1. Introduction
The principal problems of steroid hormone biosynthesis are: (a)
the chemical nature of the physiologically active steroids secreted by
the endocrine glands; and (b) the way in which these substances are
made by the cells of the glands. These problems have been investigated
almost exclusively in the Eutheria or "higher mammals." Virtually
nothing is known of steroid hormone biogenesis in other subclasses of
mammals or in birds, reptiles, amphibians, and fishes although physiologically active steroids have been found in the tissues or excreta of
representatives of some of these classes.
Early knowledge was obtained by the isolation of physiologically
active steroids and their metabolites from urine and endocrine tissues,
and understandably much of the information was obtained from animals, such as man, the ox, swine, and horse, which provided amounts of
urine or tissue large enough for isolation of steroids by classic methods.
Interesting species differences soon appeared. For instance estriol
(XXIX) appears to be formed by man alone,* and certain B ring unsaturated estrogens such as equilin (XXX) by the horse alone. However a wider search with modern micromethods, such as paper chromatography and infrared spectroscopy, for the separation and identification of steroids might reveal that the distribution of these substances is
less restricted than appears to be the case. Indeed there is already
slight evidence that this is so (Section I,B,3,&).
The earlier work provided indirect evidence on the nature of
steroid secretions. With the advent of modern micromethods it has
been possible to exploit the direct attack on the problem indicated by
the work of Vogt (41) on the secretion of the adrenal cortex in dogs
and other animals in which the adrenal vein was cannulated. As a result, knowledge of the secretion of the adrenal cortex is extensive; much
*But see Section I,B,3,Z> ( pa ge 181).
JAMES K. GRANT
different organisms. Zabin isolated C
14 -lycopene from ripening tomatoes
injected several days before with C
14 -acetate. The distribution of C
14
observed during degradation of the lycopene indicated that the carotenoid may be formed from identical isoprenoid units but failed to
show how the units are built up from acetate in the tomato. Later the
same author reported the incorporation of significant amounts of labeled
mevalonic acid into lycopene. Obviously more work is required here to
confirm the origin of the carbon atoms in the lycopene arid that the
biosynthesis of this substance is indeed different.
B. STEROID HORMONE BIOSYNTHESIS
1. Introduction
The principal problems of steroid hormone biosynthesis are: (a)
the chemical nature of the physiologically active steroids secreted by
the endocrine glands; and (b) the way in which these substances are
made by the cells of the glands. These problems have been investigated
almost exclusively in the Eutheria or "higher mammals." Virtually
nothing is known of steroid hormone biogenesis in other subclasses of
mammals or in birds, reptiles, amphibians, and fishes although physiologically active steroids have been found in the tissues or excreta of
representatives of some of these classes.
Early knowledge was obtained by the isolation of physiologically
active steroids and their metabolites from urine and endocrine tissues,
and understandably much of the information was obtained from animals, such as man, the ox, swine, and horse, which provided amounts of
urine or tissue large enough for isolation of steroids by classic methods.
Interesting species differences soon appeared. For instance estriol
(XXIX) appears to be formed by man alone,* and certain B ring unsaturated estrogens such as equilin (XXX) by the horse alone. However a wider search with modern micromethods, such as paper chromatography and infrared spectroscopy, for the separation and identification of steroids might reveal that the distribution of these substances is
less restricted than appears to be the case. Indeed there is already
slight evidence that this is so (Section I,B,3,&).
The earlier work provided indirect evidence on the nature of
steroid secretions. With the advent of modern micromethods it has
been possible to exploit the direct attack on the problem indicated by
the work of Vogt (41) on the secretion of the adrenal cortex in dogs
and other animals in which the adrenal vein was cannulated. As a result, knowledge of the secretion of the adrenal cortex is extensive; much
*But see Section I,B,3,Z> ( pa ge 181).