IN VITRO STEROID SYNTHESIS BY FOETAL RABBIT ADRENALS

1971 ◽  
Vol 68 (2) ◽  
pp. 209-218 ◽  
Author(s):  
K. Kurachi ◽  
M. Miyazaki ◽  
H. Mori ◽  
K. Matsumoto
Keyword(s):  
Isotope Dilution ◽  
Hydroxysteroid Dehydrogenase ◽  
Late Gestation ◽  
Cortical Tissue ◽  
Steroid Synthesis ◽  
Metabolic Pattern ◽  
Adrenal Tissue ◽  
Tissue Homogenates

ABSTRACT Adrenal tissue homogenates from foetal rabbits in late gestation and their mothers were incubated with [7α-3H] pregnenolone and analyzed for conversion products by reverse isotope dilution procedures. Deoxycorticosterone and corticosterone were synthesized as main products by foetal as well as by adult adrenals. In addition, small amounts of progesterone, 17-hydroxypregnenolone and cortisol were formed by both adrenals. No C19-steroids and 16α-hydroxysteroids could be found. The results indicate a similarity in the qualitative metabolic pattern of pregnenolone by adrenal cortical tissue of late gestation rabbit foetuses to that of adult rabbits. However, the activity of 3β-hydroxysteroid dehydrogenase per gram tissue in the foetal rabbit adrenal was of the order of one tenth that in the adrenals of their mothers. By using [3H] progesterone as substrate, the activities of 21-hydroxylase and 11β-hydroxylase in the foetal adrenal were similarly demonstrated to be less than that of the adrenal of the mother.

ANDROGEN SYNTHESIS IN VITRO BY ADRENAL TISSUE FROM A NEWBORN ANENCEPHALIC INFANT

1971 ◽  
Vol 50 (1) ◽  
pp. 115-122 ◽  
Author(s):  
M. M. SHAHWAN ◽  
R. E. OAKEY ◽  
S. R. STITCH
Keyword(s):  
Cord Blood ◽  
Isotope Dilution ◽  
Hydroxysteroid Dehydrogenase ◽  
Blood Levels ◽  
Adrenal Tissue ◽  
Androgen Synthesis

SUMMARY Incubation of slices of adrenal tissue from a newborn anencephalic infant with [14C]pregnenolone and [3H]progesterone yielded radioactive testosterone, androst-4-ene-3,17-dione and 11β-hydroxyandrost-4-ene-3,17-dione which were characterized by reverse isotope dilution techniques. These findings indicate the presence of C(17)—C(20) desmolase, steroid 11β-hydroxylase, 3β-hydroxysteroid dehydrogenase-isomerase and 17β-hydroxysteroid dehydrogenase enzymes in this tissue. Therefore, despite the deficient production of C19 3β-hydroxy-unsaturated steroids by the anencephalic foetus, as indicated by cord blood levels, a potential for synthesis of C19 3-oxo-4-unsaturated steroids has been demonstrated in vitro.

AROMATIZING ACTIVITY OF PLACENTAL MICROSOMAL FRACTIONS FROM EWES IN LATE GESTATION

1975 ◽  
Vol 65 (1) ◽  
pp. 117-125 ◽  
Author(s):  
M. R. MANN ◽  
L. B. CURET ◽  
A. E. COLAS
Keyword(s):  
Sharp Increase ◽  
Enzyme System ◽  
Hydroxysteroid Dehydrogenase ◽  
Relative Increase ◽  
Late Gestation ◽  
Domestic Sheep ◽  
Dramatic Rise ◽  
Oestradiol Production ◽  
Human Placentae

SUMMARY Placental microsomes from eight domestic sheep at 136–146 days of gestation were incubated with radioactive androstenedione, testosterone and dehydroepiandrosterone. Aromatizing activity was examined in the presence and absence of cortisol and the rates of both oestrone and oestradiol synthesis were measured. Oestrone predominated in preference to oestradiol in most of the incubations, a result opposite to that found with human placentae. The sharp increase in the rate of oestradiol production found in the 144- to 146-day-old placentae incubated with testosterone may indicate a more rapid increase of aromatizing than of 17β-hydroxysteroid dehydrogenase activity. The presence of cortisol in the mixtures did not significantly affect the placental aromatizing activity, indicating that there is no direct effect of cortisol on the enzyme system as measured in vitro. The dramatic rise of overall mean aromatizing activity from 4·86 ± 0·22 (s.e.m.) at 138–141 days of gestation to 12·96 ± 0·38 pmol/mg protein/min at 144–146 days (with a greater relative increase in the rate of oestradiol formation), suggests that changes in placental aromatizing activity may play an important role in maternal and foetal plasma oestrogen surges before ovine parturition.

UPTAKE AND METABOLISM OF TRITIATED OESTRADIOL AND OESTRONE BY HUMAN ENDOMETRIAL AND MYOMETRIAL TISSUE IN VITRO

1974 ◽  
Vol 62 (1) ◽  
pp. 109-123 ◽  
Author(s):  
R. G. GABB ◽  
G. M. STONE
Keyword(s):  
Hydroxysteroid Dehydrogenase ◽  
Endometrial Tissue ◽  
Human Uterus ◽  
Secretory Phase ◽  
Proliferative Phase ◽  
Significant Difference ◽  
Degree Of Oxidation ◽  
Tissue Homogenates ◽  
Uptake And Metabolism

SUMMARY Human endometrial and myometrial tissues were incubated in vitro with [3H]oestradiol-17β and [3H]oestrone to study the uptake and interconversion of these two steroids by the tissues. Endometrial tissue displayed a higher capacity for oestrogen interconversion than myometrial tissue and the oxidation of oestradiol-17β to oestrone was favoured, rather than the reverse reaction. A greater degree of oxidation was found in tissue taken from uteri in the secretory phase than in the proliferative phase. A study of the distribution of radiometabolites between 'soluble' and 'particulate' fractions of tissue homogenates showed that a greater proportion of the tissue radioactivity was associated with the 'particulate' fraction in the proliferative phase than in the secretory phase. After incubation of endometrial tissue from the secretory phase with tritiated oestrogens there was evidence of the formation of chloroform-insoluble radiometabolites and some of these were tentatively identified as oestrogen sulphates. In a second experiment, the uptake and metabolism of the same two oestrogens by tissue from leiomyomata uteri (fibroids) and normal myometrial tissue were compared. No significant difference between these tissues was found. The results suggest that the levels of 17β-hydroxysteroid dehydrogenase in the human uterus may be dependent upon the levels of oestrogens in the blood. The lack of a difference in the treatment of oestrogens by fibroid and normal myometrial tissue suggests that these tissues may have a similar mechanism for the uptake and retention of oestrogens.

STEROID BIOSYNTHESIS BY HUMAN FOETAL ADRENALS INCUBATED IN VITRO WITH [4-14C]PROGESTERONE: CHANGES WITH GESTATIONAL AGE

1970 ◽  
Vol 47 (3) ◽  
pp. 379-384 ◽  
Author(s):  
A. JOSEPHINE MILNER ◽  
I. H. MILLS
Keyword(s):  
Isotope Dilution ◽  
Gestational Age ◽  
Major Product ◽  
Adrenal Weight ◽  
Steroid Biosynthesis ◽  
Adrenal Tissue

SUMMARY Adrenals from foetuses of 13 to 27 weeks gestation were sliced and incubated with 5 μC of [4-14C]progesterone for 2 hr. The biosynthesis of cortisol, 11-deoxycortisol, androstenedione and 11β-hydroxyandrostenedione was estimated by reverse isotope dilution. Cortisol was the major product identified and the production of both cortisol and 11β-hydroxyandrostenedione increased with gestational age in approximate proportion to the increasing adrenal weight. The ratio of (cortisol plus 11-deoxycortisol) to (androstenedione plus 11β-hydroxyandrostenedione) was constant at 13, 16 and 27 weeks gestation. The production of cortisol and androstenedione from progesterone and from pregnenolone by adrenal tissue from a 27-week-old foetus is compared.

scholarly journals In-vitro steroid synthesis by the placenta of cows in late gestation and at parturition

Reproduction ◽  
1988 ◽  
Vol 83 (2) ◽  
pp. 565-573 ◽  
Author(s):  
T. S. Gross ◽  
W. F. Williams
Keyword(s):  
Late Gestation ◽  
Steroid Synthesis

THE CONVERSION OF PREGNENOLONE TO PROGESTERONE AND 16α-HYDROXYDEHYDROEPIANDROSTERONE IN VITRO BY ADRENAL TISSUE FROM A NEWBORN ANENCEPHALIC INFANT

1968 ◽  
Vol 40 (1) ◽  
pp. 29-35 ◽  
Author(s):  
M. M. SHAHWAN ◽  
R. E. OAKEY ◽  
S. R. STITCH
Keyword(s):  
Specific Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Enzymatic Conversion ◽  
Partition Chromatography ◽  
Adrenal Tissue ◽  
Enzyme Systems ◽  
Constant Specific Activity

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.

Metabolism and receptor binding of nandrolone and testosterone under in vitro and in vivo conditions

1985 ◽  
Vol 110 (3_Suppla) ◽  
pp. S31-S37 ◽  
Author(s):  
E. W. Bergink ◽  
J. A. A. Geelen ◽  
E. W. Turpijn
Keyword(s):  
Androgen Receptor ◽  
Receptor Binding ◽  
Reductase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
In Vivo Studies ◽  
Muscular Tissue ◽  
Binding Studies ◽  
Tissue Homogenates

Abstract. The metabolism and receptor binding of nandrolone (N) and testosterone (T) were studied under in vitro and in vivo conditions. The results of both in vitro incubation studes with 3H-N and 3H-T in tissue homogenates from rats and in vivo infusion studies with 3H-N and 3H-T in conscious rats show the importance of the enzymes 5α-reductase and 3α/β-hydroxysteroid-oxidoreductases in the prostate and the importance of the enzyme 17β-hydroxysteroid dehydrogenase in the kidney for the effects of N and T on these tissues. Following infusion of a combined dose of 3H-N and 3H-T there is a preferential retention at the receptor of 5α-dihydrotestosterone (DHT) over 5α-dihydronandrolone (DHN), N and T (DHT ⪢ DHN > N > T) in the prostate because T is a better substrate than N for 5α-reductase and because DHT binds more strongly to the androgen receptor than DHN, N and T. In the kidney 5α-reductase is not important; there is a preferential retention of N in T (DHN and DHT were only present in small amounts) because N is less susceptible than T for metabolic inactivation by the enzyme 17β-hydroxysteroid dehydrogenase and N binds strongly to the androgen receptor. Both in vitro and in vivo studies show that N and T were relatively stable in spleen, thymus and muscular tissue (only shown in vivo) and, as a result, the same amount of N and T was bound to the receptor in these tissues in the in vivo infusion experiment. In vitro binding studies with the androgen receptor in intact human cells show that 5α-reduction increases the affinity of T and decreases the affinity of N and of the 17α-ethyl derivative of N (3-keto-ethylestrenol). The results of the present studies explain the relatively strong effect of N, or derivatives of N, compared to that of T on tissues devoid of 5α-reductase activity (e.g. muscular tissue) and they suggest that in particular there may be a strong effect of N on tissues which in addition have a high 17β-hydroxysteroid dehydrogenase activity (e.g. kidney).

A BIOCHEMICAL AND PATHOLOGICAL INVESTIGATION OF ADRENAL TISSUES FROM PATIENTS WITH CONN'S SYNDROME

1962 ◽  
Vol 41 (3) ◽  
pp. 411-431 ◽  
Author(s):  
E. Brode ◽  
J. K. Grant ◽  
T. Symington
Keyword(s):  
Adrenal Cortex ◽  
Primary Aldosteronism ◽  
Cortical Tissue ◽  
Conn’S Syndrome ◽  
Tissue Homogenates

ABSTRACT Tumours removed surgically from patients with primary aldosteronism were investigated by histological and biochemical procedures. The formation of 1 1β-hydroxyprogesterone-14C from progesterone-14C by tumour but not normal cortical tissue homogenates has been demonstrated. The significance of this substance in the biosynthesis of aldosterone is discussed. The ratio of 17-hydroxy to 17-deoxy C21 steroids formed in vitro by tumours and zones of normal adrenal cortex has been determined and an attempt has been made to use this ratio to determine the origin of the cells of the aldosterone secreting tumours.

CONVERSION OF PREGNENOLONE TO PROGESTERONE BY RABBIT PLACENTA IN VITRO

1969 ◽  
Vol 61 (4) ◽  
pp. 577-584 ◽  
Author(s):  
K. Matsumoto ◽  
G. Yamane ◽  
H. Endo ◽  
K. Kotoh ◽  
K. Okano
Keyword(s):  
Isotope Dilution ◽  
Specific Activity ◽  
Enzyme System ◽  
Hydroxysteroid Dehydrogenase ◽  
Pregnant Rabbit ◽  
Dehydrogenase Enzyme ◽  
Constant Specific Activity

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.

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