3. LIPIDS: STEROID METABOLISM
179
Androstenedione and dehydroepiandrosterone (DHA) (XIX) have also
been detected in the adrenal venous blood of man (71), but not of
cattle (56). Further indirect evidence for the production of adrenal
androgens and estrogens in man is provided by the virilizing or feminizing effects observed in some patients with adrenal tumors. Moreover,
estrone, estradiol-17/3, and estriol have been detected and measured by
reliable modern methods in the urine of gonadectomized human subjects
(71a). There is also evidence that 18-hydroxyestrone, found in the
urine of pregnant women, may be of adrenal origin (72).
A curious and unexplained observation has recently been made by
Short and his colleagues (60). They found 20«-hydroxypregn-4-en-3-one
(XXII) in higher amounts in the adrenal venous than in the peripheral
blood of young calves. This substance has not previously been described
as an adrenocortical steroid, but it has been isolated from a number of
other tissues in man, the sheep, and the rat, where it has been regarded
as a metabolite of progesterone. It appeared in the adrenal venous
blood in increasing amounts up to the twenty-third day of life and
thereafter decreased. The presence of this steroid was quite unexpected
since the 20/?-epimer is the major compound of this type present in the
adrenal venous blood of adult cattle. The only biological activity of
the 20«-epimer known at present is that of a weak progestational agent.
f. The Adrenocortical Hormones in Classes of Animals Other Than
the Eutheria. As stated in the introduction to this section, virtually
nothing is known of steroid hormone biogenesis in subclasses and
classes of animals other than Eutheria. It is not clear at present whether
tissue homologous to the eutherian adrenal cortex is present in all vertebrates. The name "interrenai" has been suggested for the organ in certain elsamobranch fishes which appears to correspond to the adrenal
cortex in higher animals. The interrenai is rich in lipid (73) and,
where its surgical removal is possible, disturbances in the electrolyte
metabolism of the fish may follow (74). Attempts to use crude extracts
of elasmobranch interrenals to prevent the appearance of adrenal insufficiency failed in the case of adrenalectomized cats (75) but were
claimed to be successful in the case of young rats (76).
The more common teleost fishes have interrenai tissue distributed
about the cardinal veins. In the eel this tissue appears to atrophy after
hypophysectomy and regenerate after administration of mammalian
corticotropin, and to show changes in ascorbic acid content reminiscent
of those observed in mammalian adrenals (77).
A hydrocortisone-like substance, showing the reactions of the dihydroxyacetone side chain at C-17 has been detected in the plasma of
salmon, and it has been reported (78) that salmon migrating to the sea
have a higher concentration of this substance in the plasma. The latter
179
Androstenedione and dehydroepiandrosterone (DHA) (XIX) have also
been detected in the adrenal venous blood of man (71), but not of
cattle (56). Further indirect evidence for the production of adrenal
androgens and estrogens in man is provided by the virilizing or feminizing effects observed in some patients with adrenal tumors. Moreover,
estrone, estradiol-17/3, and estriol have been detected and measured by
reliable modern methods in the urine of gonadectomized human subjects
(71a). There is also evidence that 18-hydroxyestrone, found in the
urine of pregnant women, may be of adrenal origin (72).
A curious and unexplained observation has recently been made by
Short and his colleagues (60). They found 20«-hydroxypregn-4-en-3-one
(XXII) in higher amounts in the adrenal venous than in the peripheral
blood of young calves. This substance has not previously been described
as an adrenocortical steroid, but it has been isolated from a number of
other tissues in man, the sheep, and the rat, where it has been regarded
as a metabolite of progesterone. It appeared in the adrenal venous
blood in increasing amounts up to the twenty-third day of life and
thereafter decreased. The presence of this steroid was quite unexpected
since the 20/?-epimer is the major compound of this type present in the
adrenal venous blood of adult cattle. The only biological activity of
the 20«-epimer known at present is that of a weak progestational agent.
f. The Adrenocortical Hormones in Classes of Animals Other Than
the Eutheria. As stated in the introduction to this section, virtually
nothing is known of steroid hormone biogenesis in subclasses and
classes of animals other than Eutheria. It is not clear at present whether
tissue homologous to the eutherian adrenal cortex is present in all vertebrates. The name "interrenai" has been suggested for the organ in certain elsamobranch fishes which appears to correspond to the adrenal
cortex in higher animals. The interrenai is rich in lipid (73) and,
where its surgical removal is possible, disturbances in the electrolyte
metabolism of the fish may follow (74). Attempts to use crude extracts
of elasmobranch interrenals to prevent the appearance of adrenal insufficiency failed in the case of adrenalectomized cats (75) but were
claimed to be successful in the case of young rats (76).
The more common teleost fishes have interrenai tissue distributed
about the cardinal veins. In the eel this tissue appears to atrophy after
hypophysectomy and regenerate after administration of mammalian
corticotropin, and to show changes in ascorbic acid content reminiscent
of those observed in mammalian adrenals (77).
A hydrocortisone-like substance, showing the reactions of the dihydroxyacetone side chain at C-17 has been detected in the plasma of
salmon, and it has been reported (78) that salmon migrating to the sea
have a higher concentration of this substance in the plasma. The latter