Effect of Certain Toxicants on Gonadotropin-Induced Ovarian Non-Esterified Cholesterol Depletion and Steroidogenic Enzyme Stimulation of the Common Carp Cyprinus carpio in vitro

Isolated ovarian tissues from the common carp, Cyprinus carpio were incubated in vitro to obtain a discrete effect of four common toxicants of industrial origin, namely phenol, sulfide, mercuric chloride and cadmium chloride, on gonadotropin-induced alteration of nonesterified and esterified cholesterol and steroidogenic enzymes, △5-3β-HSD and 17β-HSD activity. Stage II ovarian tissue containing 30-40% mature oocytes were shown to be most responsive to gonadotropins in depleting only nonesterified cholesterol moiety and stimulating the activity of both. Safe doses of above mentioned toxicants when added separately to stage II ovarian tissue with oLH (1 μg/incubation) gonadotropin-induced depletion of nonesterified cholesterol and gonadotropin-induced stimulation of the activity of both enzymes was significantly inhibited. Esterified cholesterol remained almost unaltered. Findings clearly indicate the impairment of gonadotropin induced fish ovarian steroidogenesis by the four toxicants separately.

Changes in neurosteroid levels and steroidogenic enzyme expression in the brain of morphine dependent and withdrawing rats

BACKGROUND： Studies have demonstrated that exogenous neurosteroid treatment prevents the development of morphine tolerance and dependence, and attenuates abstinence behavior in mice. However, there are few studies on whether the levels of endogenous neurosteroids can be changed by morphine dependence and withdrawal. OBJECTIVE： To investigate the levels of various neurosteroids in rat brain following morphine dependence and withdrawal. To evaluate the expressions of steroidogenic enzyme mRNAs and proteins. To identify the relationship between neurosteroids and morphine dependence at the whole animal behavior, neural biochemistry, and molecular levels. DESIGN, TIME AND SETTING： A randomized, controlled study. Experiments were performed at the Department of Pharmacology of Hebei Medical University and Department of Pharmacology of Beathune International Peace Hospital, China, from June 2004 to October 2007. MATERIALS： Morphine hydrochloride injection （Shenyang First Pharmaceutical Factory, China）, naloxone hydrochloride （Hunan Yiqiao Pharmaceutical Co., China） and a gas chromatography-mass spectrometry system （Agilent, CA, USA） were used in this study. METHODS： Healthy adult Sprague Dawley rats were randomly divided into three groups： a morphine dependence group, morphine withdrawal group and control group （n = 20）. The rats in the morphine dependence and morphine withdrawal groups were given increasing doses of morphine （5, 10, 15, 20, 30, 40 and 50 mg/kg, intraperitoneal） to create morphine dependence. The rats in the morphine withdrawal group were injected with 2 mg/kg naloxone to precipitate withdrawal 1 hour after the last morphine injection. Rats in the control group were treated with an equal volume of saline. MAIN OUTCOME MEASURES： Following morphine dependence and withdrawal, brain levels of the neurosteroids pregnenolone, progesterone and allopregnanolone were analyzed using gas chromatography-mass spectrometry. The mRNA expression of two key steroidogenic enzymes, P450 side-chain cleavage enzyme （P450scc） and 3[B-hydroxysteroid dehydrogenase （313-HSD）, were determined in rat brain regions using reverse transcription-polymerase chain reaction. The distribution and expression of P450scc protein were visualized in brain regions associated with addiction by immunohistochemistry. RESULTS： In brain tissue from the morphine dependence group, the levels of pregnenolone and progesterone were decreased by 62% （P 〈 0.01） and 92% （P 〈 0.01 ） respectively, compared with the control group. In the morphine dependence group, the key steroidogenic enzyme P450scc mRNA was decreased in striatum （P 〈 0.05）, while 3-HSD mRNA was decreased in amygdala （P 〈 0.05）, striatum （P 〈 0.05） and frontal cortex （P 〈 0.05） compared with the control group. Morphine withdrawal induced a significant increase in the neurosteroid levels compared with the control group （P 〈 0.01）. However, there was no significant difference in the expressions of P450scc and 36-HSD mRNAs between the morphine withdrawal and control groups （P 〉 0.05）. CONCLUSION： The neurosteroid levels and expressions of steroidogenic enzymes changed similarly in morphine dependent rats, suggesting that the morphine dependence-induced decrease in neurosteroids might depend on local expression of steroidogenic enzymes in the central nervous system. However, the changes in neurosteroids in morphine withdrawal rats were not in accordance with the changes in the expression of steroidogenic enzymes, suggesting that the effects of morphine withdrawal on brain neurosteroid levels may not depend primarily on the local expression of steroidogenic enzymes in the central nervous system.

Expression of Key Steroidogenic Enzymes in Human Placenta and Associated Adverse Pregnancy Outcomes

Steroid hormones,including progestagens,estrogens,androgens,corticosteroids,and their precursor cholesterol,perform essential functions in the successful establishment and maintenance of pregnancy and normal fetal development.As the core endocrine organ at the prenatal stage,the human placenta is involved in the biosynthesis,metabolism,and delivery of steroid hormones.Steroidogenic pathways are tightly regulated by placenta-intrinsic cytochrome P450 and hydroxysteroid dehydrogenase.However,the relationship between placental steroidogenic enzyme expression and adverse pregnancy outcomes is controversial.In this review,we summarize the possible upstream regulatory mechanisms of placental steroidogenic enzymes in physiologic and pathophysiologic states.We also describe the human placental barrier model and examine the potential of single-cell sequencing for evaluating the primary functions and cellular origin of steroidogenic enzymes.Finally,we examine the existing evidence for the association between placental steroidogenic enzyme dysregulation and adverse pregnancy outcomes.

Seasonal dynamics,kinetics,and effects of 2-hydroxyestradiol-17βon some steroidogenic enzymes in the ovary of the catfish Heteropneustes fossilis

The synthesis of bioactive steroids is catalyzed by an array of enzymes of diverse properties and actions.In the present study,seasonal dynamics and kinetics of key steroidogenic enzymes,17α-hydroxylase(Cyp17a),3β-hydroxysteroid dehydrogenase(Hsd3b),20α-hydroxysteroid dehydrogenase(Hsd20a)and 20β-hydroxysteroid dehydrogenase(Hsd20b)were investigated in the female catfish Heteropneustes fossilis.Further,the effects of the estrogen metabolite 2-hydroxyestradiol-17β(2-OHE2)and human chorionic gonadotropin(hCG)on activities of the above enzymes,cytochrome P450 aromatase(Cyp19a1),and steroid products including testosterone and cortisol were determined.The enzymes under investigation showed significant seasonal variations across the annual ovarian cycle with low activity in the gonad resting phase.The enzymes Hsd3b and Cyp17a showed high activity during early oogenesis but the activities of Hsd20a and Hsd20b were higher towards late oogenesis in the spawning phase.Hsd3b and Cyp17a elicited high apparent Km values(low substrate affinity)and high apparent Vmax in the vitellogenic phase compared to the postvitellogenic phase.Hsd20a did not elicit any significant differences in the kinetic parameters between the two phases.Hsd20b showed high apparent Km values(low substrate affinity)and high Vmax in the postvitellogenic phase.The incubation of ovarian slices with 2-OHE2 for 24 h increased dose-dependently Hsd3b,Cyp17a,Hsd20a and Hsd20b activities,similar to hCG.The levels of the corresponding C21 steroid products,progesterone(P4),17α-hydroxyprogesterone(17-OHP4),17,20α-dihydroxy-4-pregnen-3-one(17,20α-DP)and 17,20β-dihydoxy-4-pregnen-3-one(17,20β-DP),and cortisol were elevated.However,2-OHE2 decreased significantly the C19 and C18 steroids,testosterone and E2 levels,and Cyp19a activity.The co-incubation with hCG and 2-OHE2 produced a synergistic effect on the enzyme activities except that of CYP19a.The co-incubation reversed the inhibitory effect of 2-OHE2.The data show that 2-OHE2 exerts a dual role on steroidogenesis,stimulating the C21 pathway and inhibiting the C19-C18 pathway,resulting in the steroidogenic shift.

Seasonal change of circulating leptin associated with testicular activities of the wild ground squirrels(Citellus dauricus)

The purpose of this study was to explore the variations in the circulating leptin concentrations of the wild ground squirrels in relation to seasonal changes in testicular activities.Hematoxylin-eosin staining showed all types of elongated spermatids and spermatogenic cells existed in the testis in April,while the primary spermatocytes and spermatogonia were most advanced stages of germ cells in June.In addition,the primary spermatocytes,secondary spermatocytes,and spermatogonia were most advanced stages of germ cells in September.The highest circulating leptin concentration was consistent with the maximum body weight results from accumulation of adipose tissue in September.The mRNA expression level of leptin receptor(Ob-R)and STAT3 was lowest in June,raised in September,and remained increased in April.Ob-R and STAT3 were stronger staining in the Leydig cells in July.Moreover,the concentrations of testosterone(T)showed the maximum values in April,the minimum values in June,and significant increases in September.Furthermore,it is worth noting that the levels of T increased with the mRNA levels of Ob-R,STAT3,StAR,and testicular steroidogenic enzymes(3β-HSD,P450c17,and P450scc).Moreover,RNA-seq analyses of testis during the different periods showed that a total of 4209 genes were differ-entially expressed genes(DEGs);further analysis revealed that DEGs related with the Jak/STAT pathways and reproduction were altered.Taken together,the results suggested that the leptin regulated testicular function through the Jak/STAT pathways and testicular steroidogenic factor expressions.