GLUCOCORTICOID SYNTHESIS FROM PREGNENOLONE BY SHEEP FOETAL ADRENALS IN VITRO

1973 ◽  
Vol 58 (3) ◽  
pp. 485-491 ◽  
Author(s):  
I. J. DAVIES ◽  
K. J. RYAN

SUMMARY [7-3H]Pregnenolone was incubated with homogenates of adrenal glands from two 100-day-old sheep foetuses. Cortisol and corticosterone were isolated and identified by reverse isotope dilution and recrystallization to constant specific activity. Together these two compounds accounted for 12% and 17% of the substrate with the two tissue preparations. Other C21 and C19 metabolites which were sought were not present in appreciable quantities. Additional incubations were done with the adrenals of lamb foetuses ranging in age from 110 days of gestation to the immediate newborn period. Glucocorticoidogenic capacity similar to that of the 100-day-old foetuses was demonstrated throughout this period and no age-related change was evident. These results demonstrate that the lamb foetal adrenal has a substantial enzymic capacity for glucocorticoid synthesis throughout at least the last third of gestation. In conjunction with the observations of others, these experiments support the hypothesis that during this period of gestation the lamb foetal adrenal is actively synthesizing glucocorticoids in a manner which is similar to the lamb at term and the adult sheep.

1969 ◽  
Vol 61 (4) ◽  
pp. 577-584 ◽  
Author(s):  
K. Matsumoto ◽  
G. Yamane ◽  
H. Endo ◽  
K. Kotoh ◽  
K. Okano

ABSTRACT A placental preparation from rabbits in mid-pregnancy was shown to convert 7α-3H-pregnenolone to radioactive progesterone in vitro. The extent of conversion per gram tissue by the placenta was about one hundredth of that by the ovary from the pregnant rabbit. Identification of radioactive progesterone was accomplished by reverse isotope dilution and recrystallization to constant specific activity. However, no Δ5-3β-hydroxysteroid dehydrogenase was found histochemically in the trophoblast and other tissues of the rabbit placenta. No ability to convert 7α-3H-pregnenolone to radioactive 20α-hydroxypregn-4-en-3-one, 20β-hydroxypregn-4-en-3-one, corticosterone, cortisol, androst-4-ene-3,17-dione, dehydroepiandrosterone, 17β-oestradiol and oestrone in placental preparation from rabbits could be demonstrated. The data demonstrate the presence of a 3β-ol-dehydrogenase enzyme system in the rabbit placenta.


Metabolism ◽  
1996 ◽  
Vol 45 (1) ◽  
pp. 82-91 ◽  
Author(s):  
Ole Hother-Nielsen ◽  
Jan Erik Henriksen ◽  
Jens Juul Holst ◽  
Henning Beck-Nielsen

1969 ◽  
Vol 61 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Hubertus A. van Leusden ◽  
Maria Siemerink

ABSTRACT Vesicles of hydatidiform moles were incubated in the presence of [7α-3H]pregnenolone, After the incubation and extraction of tissues and media, 17α-hydroxy-pregnenolone*, 17α-hydroxy-progesterone and progesterone were identified using a number of TLC systems, followed by crystallization to a constant specific activity. [7α-3H] pregnenolone was not converted to oestrone, 17β-oestradiol and oestriol. The experimental findings indicate that hydatidiform moles, like full term placentas, are deficient in the enzymes necessary to convert C21 to C19 steroids. The production of 17α-hydroxy-progesterone and progesterone in the molar trophoblast in situ may contribute to the considerable urinary excretion of pregnanetriol and pregnanediol in patients with hydatidiform moles.


1977 ◽  
Vol 75 (2) ◽  
pp. 187-195 ◽  
Author(s):  
D. I. FATTAH ◽  
B. J. WHITEHOUSE ◽  
G. P. VINSON

Rat adrenal capsules incubated with [3H]18-hydroxydeoxycorticosterone (18-OH-DOC) and [3H]18-hydroxycorticosterone gave appreciable yields of aldosterone from both precursors, similar in size to those obtained from labelled corticosterone, deoxycorticosterone and progesterone under the same conditions. After feeding rats for 14 days on a flour diet deficient in sodium, aldosterone production from endogenous precursors in vitro was increased twofold compared with that by adrenal glands from animals receiving the flour diet with 1% sodium chloride added (control diet). When adrenal capsules from animals on the low-sodium flour diet were incubated with high specific activity [3H]18-OH-DOC (sp. act. 40 Ci/mmol), the yield of [3H]aldosterone was increased two- to threefold compared with that produced by capsules from animals on the control diet. When capsules were incubated with low specific activity [3H] 18-OH-DOC and [14C]corticosterone (sp. act. 52 mCi/mmol) only the yield of [14C]aldosterone was increased. Yields of labelled 18-hydroxycorticosterone from all precursors tested were increased three- to fourfold in animals receiving the low-sodium diet relative to the controls. The results show that 18-OH-DOC can be an effective precursor for aldosterone formation by rat adrenal capsules, and that production of aldosterone and 18-hydroxycorticosterone from this precursor can be stimulated by a low-sodium diet. This suggests the existence of an alternative pathway for aldosterone biosynthesis involving 18-OH-DOC as an intermediate.


1973 ◽  
Vol 74 (1) ◽  
pp. 177-185 ◽  
Author(s):  
Hisanori Kasai ◽  
Shutaro Mizutani ◽  
Keishi Matsumoto

ABSTRACT [3H]Testosterone (2.0 μg/300 μCi or 3.3 μg/500 μCi) was injected into each of 23 mice, aged 45 days and the distribution of tritium among certain unconjugated steroids in the whole tissue, nuclear, mitochondrial + microsomal and cytosol fractions from the testes, liver, muscle, blood and prostate + seminal vesicle was determined 1 h after the injection. [3H] 17β-Hydroxy-5α-androstan-3-one could be clearly shown in the whole tissue and the three fractions from the testes and prostate-seminal vesicle, but none was identified in any of the fractions from androgen-unresponsive tissues such as the liver, muscle and blood. However, the levels of [3H] 17β-hydroxy-5α-androstan-3-one were much higher in the prostate-seminal vesicle than in the testes. The levels of [3H]5α-androstane-3α,17β-diol in all the fractions from the testes as well as those from the prostate-seminal vesicle were in the order of ten times the levels in the corresponding fractions from the liver and muscle. Identification of [3H] steroids was accomplished by reverse isotope dilution and re-crystallization to constant specific activity. It would appear that the mouse testes belong to androgen-responsive tissues and that 5α-androstane-3α,17β-diol and 17β-hydroxy-5α-androstan-3-one may play a role in the testes.


1961 ◽  
Vol 36 (3) ◽  
pp. 455-461 ◽  
Author(s):  
Brian Little ◽  
Ann Shaw

ABSTRACT The conversion of progesterone to 17α-hydroxyprogesterone by the soluble fraction of human placenta has been demonstrated in vitro. The incubation system contained the soluble supernatant fluid fraction of placental homogenate (105 000 × g), progesterone 4-14C as substrate, authentic 17α-hydroxyprogesterone as trap and a reduced triphosphopyridine nucleotide generating system as cofactor. The 17α-hydroxyprogesterone formed was isolated chromatographically and radiochemical purity was demonstrated by constant specific activity in a counter current distribution. Constant specific activity and radiochemical purity of the oxidation product and the acetylated derivative was also shown.


1968 ◽  
Vol 40 (1) ◽  
pp. 29-35 ◽  
Author(s):  
M. M. SHAHWAN ◽  
R. E. OAKEY ◽  
S. R. STITCH

SUMMARY Adrenal tissue, largely composed of the definitive zone, from a newborn anencephalic infant, contained the following enzyme systems: (1) a Δ5-3β-hydroxysteroid dehydrogenase for pregnenolone, demonstrated by the conversion of [14C]pregnenolone to [14C]progesterone; (2) a C(17)-C(20) desmolase, and (3) a steroid 16α-hydroxylase, demonstrated by the conversion of [14C]pregnenolone to [14C]3β, 16α-dihydroxyandrost-5-en-17-one. The metabolites could not be separated from carrier steroids during sequential partition chromatography. [14C]Progesterone was identified by recrystallization to constant specific activity. [14C]3β, 16α-Dihydroxyandrost-5-en-17-one was identified by enzymatic conversion to [14C]16α-hydroxyoestrone followed by reduction to oestriol and determination of the specific activity of the oestriol after partition chromatography. It is suggested that these enzymes may play some part in the production of cortisol by the newborn anencephalic infant, and in the provision of precursors for placental oestriol production.


1969 ◽  
Vol 44 (4) ◽  
pp. 557-566 ◽  
Author(s):  
M. M. SHAHWAN ◽  
R. E. OAKEY ◽  
S. R. STITCH

SUMMARY Adrenal tissue from newborn anencephalic infants converted pregnenolone and progesterone to cortisol, 17α-hydroxyprogesterone, corticosterone, 17α,21-dihydroxyprogesterone, deoxycorticosterone and 1 1β-hydroxyprogesterone in vitro. These metabolites were identified by recrystallization to constant specific activity after multiple chromatography and derivative formation. The results demonstrate a potential for corticosteroid biosynthesis, at least from pregnenolone and progesterone, by the adrenals of the anencephalic infant, and therefore possibly by the definitive zone of the adrenal of the normal newborn infant.


1973 ◽  
Vol 58 (1) ◽  
pp. 75-87 ◽  
Author(s):  
DENISE MADILL ◽  
J. M. BASSETT

SUMMARY Adrenal glands from 24 foetal lambs (100–145 days gestation) and eight postnatal lambs (birth to 25 days of age) were used to study developmental changes in the responsiveness of the lamb adrenal to stimulation by synthetic adrenocorticotrophin (ACTH). A continuous flow incubation system in vitro (perifusion) was used in these studies. Addition of ACTH to the perifusion medium (0·3 μg Synacthen/ml) significantly increased the rate of corticosteroid release (as measured by a protein-binding assay) by adrenal tissue from foetuses of all ages studied. With tissue from foetuses of 137 days gestation or less, corticosteroid release during ACTH stimulation was < 2 μg/100 mg tissue in the 3 h following addition of ACTH to the perifusion medium. With tissue from foetuses older than this, the rate of corticosteroid release stimulated by ACTH increased as foetal age increased. At 145 days gestation (just before birth) release was 6·8 μg/100 mg tissue and in postnatal lambs less than 1 day old it was 12·3 μg/100 mg tissue during the 3 h following the start of stimulation. This increase in the response of the foetal adrenal to ACTH stimulation paralleled the increases in adrenal weight and plasma corticosteroid concentration which occurred before birth. With tissue from older lambs ACTH-stimulated corticosteroid release was 5·5 μg/100 mg tissue/3 h, a value comparable to that of 5·6 μg/100 mg tissue/3 h obtained with adrenal tissue from adult sheep. Separation of corticosteroids in the perifusion medium by chromatography on LH 20 Sephadex indicated that adrenals from younger foetuses (< 137 days gestation) released approximately equal amounts of cortisol and corticosterone, whereas adrenals from older foetuses and postnatal lambs released mainly cortisol. Pituitary tissue from all foetuses stimulated corticosteroid release from adrenal tissue of adult sheep, implying that foetal pituitary stores of ACTH do not limit development of foetal adrenal cortex function during the last third of gestation. The results indicate that there is a marked increase during the last week of gestation in the responsiveness of the foetal adrenal to ACTH stimulation and that this increase is related to maturation of corticosteroid biosynthetic pathways during this period.


1972 ◽  
Vol 70 (2) ◽  
pp. 351-359
Author(s):  
J.-P. Weniger ◽  
A. Zeis

ABSTRACT Wolffian ducts from 17½-day-old rat embryos were cultivated in vitro in the presence of [4-14C] testosterone. The most important metabolite, if not the single one, was dihydrotestosterone, which was identified by recrystallization to constant specific activity. The discussion turns on the role dihydrotestosterone may play in normal Wolffian duct development. In parallel studies, testosterone was found to be converted into dihydrotestosterone, androsterone, androstanedione and 5α-androstan-3α,17β-diol by the kidney. Androsterone and androstanedione were metabolites of testosterone in the liver.


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