Stimulation of aromatase activity in the fetal rat gonads by cAMP and FSH

1988 ◽  
Vol 119 (3) ◽  
pp. 381-385 ◽  
Author(s):  
J.-P. Weniger ◽  
A. Zeis
Keyword(s):  
Specific Activity ◽  
Isotopic Dilution ◽  
Aromatase Activity ◽  
Fetal Rat ◽  
Estrogen Synthesis ◽  
Fetal Rats ◽  
Stimulation Of ◽  
Constant Specific Activity

Abstract. The gonads from 17- to 21-day-old fetal rats were cultured in vitro in the presence of [3H]testosterone and in the presence or absence of cAMP or FSH, and estrone and estradiol formed were measured by double isotopic dilution and recrystallization to constant specific activity. Estrogen synthesis by testes was stimulated by both cAMP and FSH as early as at 18 days of gestation. FSH did not enhance aromatase activity in ovaries, although cAMP did. It is remarkable that FSH controls estrogen synthesis in the testis earlier than in the ovary.

Stimulation of aromatase activity in the fetal rat testis by cyclic AMP and FSH

1988 ◽  
Vol 118 (3) ◽  
pp. 485-489 ◽  
Author(s):  
J.-P. Weniger ◽  
A. Zeis
Keyword(s):  
Cyclic Amp ◽  
Specific Activity ◽  
Isotopic Dilution ◽  
Aromatase Activity ◽  
Dibutyryl Cyclic Amp ◽  
Rat Testis ◽  
Fetal Rat ◽  
Fetal Rats ◽  
Stimulation Of

ABSTRACT The effect of dibutyryl cyclic AMP and FSH on oestrogen biosynthesis was investigated in testes from 18- to 21-day-old fetal rats cultured in vitro in the presence of tritiated testosterone. Oestrone and oestradiol concentrations were measured by determination of constant specific activity after isotopic dilution. Dibutyryl cyclic AMP and FSH markedly stimulated the conversion of testosterone into both oestrone and oestradiol at all stages studied. Oestradiol synthesis was stimulated by two- to sevenfold, while stimulation of oestrone synthesis was even greater. The results demonstrate that the aromatase enzyme system of the fetal rat testis responds to cyclic AMP and FSH. J. Endocr. (1988) 118, 485–489

Aromatase activity in the mare ovary during estrous cycle. Measurement of endogenous steroids and of their in vitro inhibitory effect

1993 ◽  
Vol 129 (6) ◽  
pp. 536-542 ◽  
Author(s):  
Hakima Amri ◽  
Pierre Silberzahn ◽  
Ihsan Al-Timimi ◽  
Jean-Luc Gaillard
Keyword(s):  
Follicular Fluid ◽  
Luteal Phase ◽  
Physiological Role ◽  
Inhibitory Effect ◽  
Aromatase Activity ◽  
Estrogen Production ◽  
Estrogen Synthesis ◽  
Luteal Tissue ◽  
Endogenous Steroids

This present study was undertaken to clarify estrogen synthesis in the mare ovary. First of all, an evaluation of endogenous steroid contents was carried out in the follicular fluid and in the luteal tissue at different stages of the luteal phase. Radioimmunoassays were performed after separation and purification of each hormone by chromatography. High amounts of conjugated (0.9 mg/l) and unconjugated (4 mg/l) estradiol-17β were found in the follicular fluid of the large follicules (50 mm). These concentrations of estrogens decreased drasticaly in the luteal tissue, and only low levels of circulating estrogens are found during the luteal phase. On the other hand, a high aromatization ability has been evidenced in the cyclic corpus luteum in vitro. In an attempt to clarify the regulation of estrogen synthesis, we have tested the inhibitory effect of several endogenous steroids on equine ovarian aromatase activity. 5α-Dihydrotestosterone appeared to be the most potent competitive inhibitor (Ki= 181 nmol/l) of aromatase activity, while the addition of a 3-sulfate group induced a slump in the inhibitory potency of estrone (Ki= 397 nmol/l vs 2206 nmol/l) and dehydroepiandrosterone (Ki = 291 nmol/l vs 6157 nmol/l). The physiological role of these conjugated steroids has not been known until now; we suggest that they would play a role in protecting aromatase from inhibition, in vivo. The high amounts of progesterone found in the luteal tissue (1.3 g/kg of proteins) might play a role in the regulation of estrogen production either by suppressing the induction of aromatase synthesis or by inhibiting the activity of the enzyme complex.

Effect of glucose on insulin biosynthesis and β cell ultrastructure in cultured fetal rat pancreas

1984 ◽  
Vol 100 (2) ◽  
pp. 155-160 ◽  
Author(s):  
R. D. G. Milner ◽  
A. Cser ◽  
G. H. Cope
Keyword(s):  
Cell Ultrastructure ◽  
Insulin Biosynthesis ◽  
Cell Nuclei ◽  
Β Cell ◽  
Absolute Volume ◽  
Fetal Rat ◽  
Insulin Granules ◽  
Fetal Rats ◽  
Exocrine Cell

ABSTRACT Pancreatic rudiments from 14-day fetal rats were cultured whole for 8 days in medium containing 5·5 or 16·5 mmol glucose/l (1G or 3G medium). Rudiments grown in 3G medium (3G cells) contained more DNA and insulin than those grown in 1G medium (1G cells) but there was no alteration in the insulin/DNA ratio or the fractional area of the rudiment occupied by insulin-containing cells. Morphometric analysis of ultrastructure revealed that the β cells grown in 3G medium were smaller and had smaller nuclei than those grown in 1G medium. The size of exocrine cell nuclei in 1G or 3G medium was similar. Insulin granules occupied a greater proportion of the cytoplasmic volume in rudiments grown in 3G medium although the mean absolute volume of insulin granules per cell grown in 1G and 3G media was similar. Hence the residual cytoplasmic volume (cell—nucleus and granules) of 3G cells was less than that of 1G cells. Insulin granules from 3G cells had smaller granule sacs and cores than those from 1G cells. It is concluded that glucose stimulates the growth of rat fetal pancreas in vitro and has important effects on β cell ultrastructure. J. Endocr. (1984) 100, 155–160

scholarly journals Effect of β-agonist on the dexamethasone-induced expression of aromatase by the human monocyte cells

2017 ◽  
Vol 6 (2) ◽  
pp. 82-88 ◽  
Author(s):  
Masatada Watanabe ◽  
Shuji Ohno ◽  
Hiroshi Wachi
Keyword(s):  
Atopic Dermatitis ◽  
Human Skin ◽  
Human Monocyte ◽  
Skin Thickness ◽  
Aromatase Activity ◽  
Gene Transcript ◽  
Aromatase Expression ◽  
Estrogen Synthesis ◽  
Peripheral Monocyte

Emerging evidence suggests that sex steroids are important for human skin health. In particular, estrogen improves skin thickness, elasticity and moisture of older women. The major source of circulating estrogen is the ovary; however, local estrogen synthesis and secretion have important roles in, for example, bone metabolism and breast cancer development. We hypothesized that infiltrated peripheral monocytes are one of the sources of estrogen in skin tissues. We also hypothesized that, during atopic dermatitis under stress, a decline in the hypothalamus–pituitary–adrenal axis (HPA) and facilitation of the (hypothalamus)–sympathetic–adrenomedullary system (SAM) attenuates estrogen secretion from monocytes. Based on this hypothesis, we tested aromatase expression in the human peripheral monocyte-derived cell line THP-1 in response to the synthetic glucocorticoid dexamethasone (Dex), the synthetic β-agonist isoproterenol (Iso) and the β-antagonist propranolol (Pro). Dex mimics glucocorticoid secreted during excitation of the HPA, and Iso mimics catecholamine secreted during excitation of the SAM. We found that aromatase activity and the CYP19A1 gene transcript were both upregulated in THP-1 cells in the presence of Dex. Addition of Iso induced their downregulation and further addition of Pro rescued aromatase expression. These results may suggest that attenuation of estrogen secretion from peripheral monocytes could be a part of the pathology of stress-caused deterioration of atopic dermatitis. Further examination using an in vitro human skin model including THP-1 cells might be a valuable tool for investigating the therapeutic efficacy and mechanism of estrogen treatment for skin health.

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
Keyword(s):  
Isotope Dilution ◽  
Adrenal Glands ◽  
Specific Activity ◽  
Newborn Period ◽  
Adult Sheep ◽  
Age Related ◽  
Period Of Gestation ◽  
Constant Specific Activity

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.

FORMATION OF 17α-HYDROXY-PREGNENOLONE, 17α-HYDROXY-PROGESTERONE AND PROGESTERONE BY HYDATIDIFORM MOLES IN VITRO

1969 ◽  
Vol 61 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Hubertus A. van Leusden ◽  
Maria Siemerink
Keyword(s):  
Urinary Excretion ◽  
Specific Activity ◽  
Full Term ◽  
Hydroxy Progesterone ◽  
Experimental Findings ◽  
Hydatidiform Moles ◽  
Constant Specific Activity

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.

A quantitative and interspecific test for biological activity of anti-mullerian hormone: the fetal ovary aromatase assay

Development ◽  
1992 ◽  
Vol 114 (3) ◽  
pp. 721-727 ◽  
Author(s):  
N. di Clemente ◽  
S. Ghaffari ◽  
R.B. Pepinsky ◽  
C. Pieau ◽  
N. Josso ◽  
...  
Keyword(s):  
Biological Activity ◽  
Chick Embryo ◽  
Cyclic Amp ◽  
Species Specificity ◽  
Human Protein ◽  
Aromatase Activity ◽  
Fetal Rat ◽  
Fetal Ovary ◽  
Quantitative Bioassay

Anti-Mullerian hormone (AMH), also known as Mullerian-inhibiting substance or factor, has previously been shown to sex-reverse the steroidogenic pattern of fetal mammalian ovaries through repression of aromatase biosynthesis. Study of the ontogeny of the response of cyclic AMP-stimulated aromatase activity of rat fetal ovaries to AMH has allowed us to develop a quantitative bioassay for the hormone. Linear responses as a function of the logarithm of AMH concentration were observed over ranges of 0.2-7.5 micrograms/ml for the bovine protein and 0.15-2 micrograms/ml for the human protein, with a maximal decrease in aromatase activity of 90% for both proteins. Under the same in vitro conditions, AMH treatment did not affect cyclic AMP-stimulated fetal rat testicular aromatase activity. Partially purified chick AMH also decreased rat ovarian aromatase activity, allowing us to use this test to study AMH ontogeny in chick gonads. Analysis of the species specificity of AMH repression of ovarian aromatase activity indicated that turtle and rat fetal ovaries responded to AMH of other vertebrate classes, whereas aromatase activity of chick embryo ovaries could be repressed only by the homospecific hormone.

scholarly journals Purification and properties of d-myo-inositol 1,4,5-trisphosphate 3-kinase from bovine iris sphincter smooth muscle: effects of protein phosphorylation in vitro and in intact muscle

1995 ◽  
Vol 308 (3) ◽  
pp. 1009-1016 ◽  
Author(s):  
X L Wang ◽  
R A Akhtar ◽  
A A Abdel-Latif
Keyword(s):  
Protein Kinase ◽  
Specific Activity ◽  
Soluble Fraction ◽  
Deae Cellulose ◽  
Sphincter Muscle ◽  
Sds Page ◽  
Intact Muscle ◽  
Stimulation Of ◽  
Iris Sphincter

Stimulation of bovine iris sphincter muscle with carbachol (10 microM) increased accumulation of Ins(1,4,5)P3 (InsP3) and Ins(1,3,4,5)P4 (InsP4) by 86 and 32% respectively. Addition of isoproterenol (5 microM) to muscle pretreated with carbachol reduced the 3H-radioactivity in InsP3 by 30% and increased that of InsP4 by 41%. InsP3 3-kinase was predominantly localized in the soluble fraction (110,000 g supernatant) of the iris sphincter. The enzyme was purified from this fraction by sequential chromatography on DEAE-cellulose, calmodulin (CAM)-agarose affinity, and Mono-Q anion-exchange columns. The specific activity of the purified enzyme was 1.94 mumol/min per mg protein with a purification of 114-fold, compared with the cytosolic fraction of the muscle. SDS/PAGE showed the enzyme to be associated with a protein band corresponding to 50 kDa. In the presence of 10 microM Ca2+, CaM dose-dependently stimulated the enzyme. InsP3 3-kinase specifically phosphorylated InsP3 with an apparent K(m) of 0.56 microM and a Vmax. of 2.5 mumol/min per mg protein. The stimulatory effect of CaM was due to a change in Vmax. and not in its K(m). The enzyme was maximally active at pH 7.0-7.5. Phosphorylation of the purified InsP3 3-kinase with protein kinase A increased its activity; in contrast, phosphorylation with protein kinase C inhibited the enzyme activity. Treatment of the intact iris sphincter with isoproterenol or phorbol 12,13-dibutyrate resulted in stimulation of InsP3 3-kinase activity in the soluble fraction and this activation was preserved on SDS/PAGE and renaturation. These results indicate that the bovine iris sphincter contains a Ca-CaM-dependent InsP3 3-kinase which can be differentially regulated, both in vitro and in intact muscle, by protein kinases A and C.

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