Kinetic studies of the applicability of the common site concept to the 3β-hydroxysteroid dehydrogenase: 5-ene-3-ketosteroid isomerase activities of human placental microsomes

Pregnenolone (3β-hydroxy-5-pregnen-20-one) and DHA (3β-hydroxy-5-androsten-17-one), substrates for 3β-hy-droxysteroid dehydrogenase (3β-HSD), with K_M values of 15–40 nM, were ineffective inhibitors of 5-ene-3-ketosteroid isomerase (isomerase), with K_I values >40 μM in each case. Progesterone and androstenedione (4-androstene-3, 17-dione), 3β-HSD inhibitors with K_I values of 5.0 μM and 0.8 μM respectively, were also relatively ineffective inhibitors of isomerase, with K_I values of 30 μM and 16.5 μM respectively. Exposure of microsomes to hydrogen peroxide, which significantly increases the K_M for pregnenolone as a 3β-HSD substrate, had no effect on the K_M for the isomerase substrate 5-pregnene-3, 20-dione.It is concluded that the data do not support the common site concept with regard to the conversion of pregnenolone to progesterone by human placental microsomes.     

Prostaglandins and thromboxanes in amniotic fluid during rivanol-induced abortion and labour

Abortion or delivery were induced by extra-amniotic instillation of Rivanol during the second trimester in twelve patients and during the third trimester in two patients with fetal death and one patient with fetal acrania. Serial sampling of amniotic fluid was performed through a transabdominal catheter and the levels of free arachidonic acid (AA), prostaglandin F₂α (PGF₂α), prostaglandin E₂ (PGE₂), 6-keto-prostaglandin F₁α (6-keto-PGF₁α) and thromboxane B₂ (TXB₂) were determined. The levels of AA, PGF₂α, PGE₂, 6-keto-PGF₁α and TXB₂ in amniotic fluid increased significantly during induction with the exception of AA in fetal death which was high and remained constant during induction. Furthermore, PGF₂α, 6-keto-PGF₁α and TXB₂ were all significantly correlated to AA.These observations suggested that free AA is released during Rivanol-induction of abortion and labour giving an increased synthesis of PGF₂α, PGE₂ prostacyclin and thromboxane A₂ in the fetal membranes and the decidua but not in the fetus. This increase might be relevant for the initiation and progress of abortion and labour in these patients.     

透骨川椒汤在妇科慢性盆腔炎治疗中的临床疗效观察

目的:探讨透骨川椒汤在妇科炎症治疗中的应用价值.方法:收集妇科慢性盆腔炎病例508例,分为治疗组和时照组各254例,两组除相同的基础治疗外,治疗组加用透骨川椒汤治疗,并对比两组疗效.结果:治疗组治愈率为50.4%,明显高于对照组的28.3%(P＜0.05).治疗组与对照组的治疗无效率比较无显著性差异(P＞0.05).结论:透骨川椒汤在治疗妇科慢性盆腔炎效果可靠,有着较好的应用前景.     

The molecular weight and substrate specificity of 20 β-hydroxysteroid dehydrogenase from Streptomyces hydrogenans

The molecular weight of 20β-hydroxysteroid dehydrogenase was 111,000 when determined by agarose gel fitration and 106,000 by density gradient centrifugation. From gel electrophoresis in sodium dodecyl sulfate, after treatment with urea and 2-mercaptoethanol, the molecular weight was 27,000, consistent with the native molecule containing four subunits. After gel electrophoresis at pH 8.1, a single band was detected which stained for protein and activity with 5α-pregnan-20β-ol-3-one and 5α-androstan-3α,17β-diol. 20β-hydroxysteroid dehydrogenase was inactivated at pH 4.5 and the time course of inactivation was independent of the steroid used for activity measurements. Steroid substrates did not protect 20β-hydroxysteroid dehydrogenase against acid inactivation or affect enzyme fluorescence. It was concluded that the activity observed with the two substrates occurred at the same active center and that under the experimental conditions little steroid was bound to the enzyme in the the absence of coenzyme.     

Inhibition of 17β-hydroxysteroid dehydrogenase (17β-HSD) activities of human placenta by steroids and non-steroidal hormone agonists and antagonists

Various naturally occurring steroids, synthetic steroid derivatives and non-steroidal hormone agonists and antagonists were assayed as inhibitors of human placental 17β-HSD activities. Microsomal 17β-HSD was inhibited by C₁₈ -,C₁₉- and C₂₁-steroids. Soluble 17β-HSD was highly specific for C₁₈-steroids. In contrast to the soluble activity, the microsomal enzyme also had a strong affinity for ethinylestradiol (K_I=0.3 μM) and danazol (K_I=0.6 μM); anabolic steroids and norethisterone were weaker inhibitors. Of the non-steroids tested only diethylstilbestrol and o-demethyl CI-680 were inhibitors and they showed a greater affinity for soluble 17β-HSD.K_I-values for estradiol-17β, (0.8 μM), progesterone (27.0 μM) and 20α-dihydroprogesterone (1.5 μM) were comparable to reported tissue levels of these compounds, consistent with a possible competition in vivo among naturally occurring C₁₈-, C₁₉-, and C₂₁-steroids for the active site of microsomal 17β-HSD.     

Leukotrienes and myometrial activity of the term pregnant uterus

Biopsies from different segments of the pregnant human uterus were superfused in organ chambers and contractile activity was registered. Leukotriene C₄(LTC₄) caused inhibition of spontaneous but not noradrenaline induced contractile activity in strips from the cervix. This effect occured both in early pregnancy and at term. However, the lower and the upper uterine segment of the term pregnant uterus did not respond to LTC₄. The results represent a documentation of the segmental differentiation in the uterine response to eicosanoids.     

Effectiveness of prostagland in F2α in restoration of HMG-HCG induced ovulation in indomethacin-treated rhesus monkeys

Six mature female rhesus monkeys were treated with HMG-HCG in control cycles at doses adjusted to induce ovulation while avoiding superovulation. Occurrence of ovulation was determined by observation of fresh ovulation points at laparotomy 48 to 120 hours following HCG. In subsequent cycles animals were treated with indomethacin (treatment days 4 through 10) together with the established dose of HMG-HCG. In 8 cycles indomethacin 5 mg/kg was given i.m. once daily; in 9 cycles 10 mg/kg i.m. was administered in 2 divided doses. Following this, PGF₂α (3 mg t.i.d. s.c.) was administered for 3 days together with indomethacin 10 mg/kg and HMG-HCG, beginning on the day prior to HCG. Determinations of progesterone were performed by RIA on treatment days 4, 7, 10, and 11. Eleven of the 13 control cycles were ovulatory. With indomethacin 5 mg/kg/day, 5 of 8 cycles were ovulatory but ovulation was delayed in 2 instances. Of 9 cycles using indomethacin 10 mg/kg/day only 1 was ovulatory. When PGF₂α was administered in subsequent cycles along with indomethacin (10 mg/kg) and HMG-HCG, ovulation occurred in 13 of 19 cycles. These data suggest that local ovarian PGF₂α may be essential in the mechanics of follicle rupture in gonadotropin-treated rhesus monkeys.     

Influence of interferon on human monocyte to macrophage development

The effect of interferon-α (Wellferon) on human monocyte to macrophage maturation in vitro has been investigated. Cell volume and three markers, acid phosphatase, leucine aminopeptidase, and phagocytosis, which increase with maturation, have been studied employing recently developed flow cytofluorometric techniques. The increase in cell volume and in the expression of all three markers was inhibited in a dose-dependent manner in monocyte cultures given 50–300 U/ml of interferon within 2 hr of culture initiation. An initial dose of 300 U/ml of interferon, removed from the cultures after 24 hr, was as effective in inhibiting the development of each of the markers as three 100 U pulses on three consecutive days, and as effective as 300 U interferon left in throughout the culture period. Histogram analysis of marker expression indicated that all monocytes, and not a subpopulation, were affected by the interferon. Cytotoxic activity of freshly isolated monocytes rapidly decayed when the cells were cultured under standard maturation conditions. The addition of interferon to the cultures prevented the loss of this activity while also preventing the development of more mature cells. It appears that maintenance of the cytotoxic state is one influence of interferons; however, it may be that these cells have also been directed toward alternate pathways of macrophage differentiation.     

Inhibition of in vitro human chorionic gonadotropin-stimulated testosterone production in testis and of ovulation in the rat by charcoal-treated rat testicular extract

Previously, we described the presence of a factor obtained from a 105,000 X g supernatant of rat testis that was found to inhibit human chorionic gonadotropin (hCG) binding to gonadal receptors. In the present study, similarly prepared testicular extract was tested for its effects on in vitro hCG-stimulated testosterone production by isolated testis interstitial cells and for its effect on spontaneous ovulation in the rat. Incubation of interstitial cells with charcoal-treated extract significantly inhibited the steroidogenic response to hCG in a dose-related manner. This inhibition was also apparent after heating the extract for 10 min at 100 degrees C. Preincubation of the cells with charcoal-treated extract resulted in an inhibitory effect that was not readily reversed by subsequent addition of hCG, revealing an element of irreversibility in the mechanism of inhibition. A single i.p. injection of testicular extract given between 1430-1630 h of proestrus inhibited spontaneous ovulation in the rat. This effect was also observed after heating the extract for 10 min at 100 degrees C; in contrast, no significant effect was obtained with the injection of a similar dose of liver extract. Administration of 5 IU hCG after pretreatment with the testicular extract did not reverse the inhibitory effect on ovulation, indicating that this effect was probably not exerted at the hypothalamus-pituitary level. It is concluded that the aqueous testicular extract contains a factor able to antagonize the physiological events mediated by luteinizing hormone (LH)/hCG, and that this factor is consistent with the presence of an LH/hCG-binding inhibitory activity in rat testis.     

Inhibiton of human placental 17 beta-hydroxysteroid dehydrogenase by steroids and nonsteroidal alcohols: aspects of inhibitor structure and binding specificity

Inhibition of human placental 17β-hydroxysteroid dehydrogenase by C₁₈ and C₁₉ steroids and nonsteroidal alcohols was assayed at pH 9.0 with 17β-estradiol 3-methyl ether and NAD⁺ as reactants. The nonstaroidal alcohols tested were poor inhibitors. Cyclopentanol and cyclohexanol had K_i values greater than 5 mm. Nonaromatic C₁₈ and C₁₉ steroids with oxygen functions at both positions 3 and 17 gave no detectable inhibition or had K_i, values greater than or equal to 160 μm. 3μ-Hydroxy-5,16-androstadiene, 5-androsten-3β-ol, 1,3,5(10)-estratrien-3-ol, and 1,3,5(10),16-estratetraen-3-ol, steroids lacking a C(17) oxygen function, had K_i values of 1.8, 6.0, 0.04, and 0.17 μm, respectively, demonstrating that both C₁₈ and C₁₉ steroids can bind at the steroid site. Binding specificity is narrowed and binding affinity for nonaromatic steroids weakened by oxygen functions at C(17) or both C(3) and C(17). The structural implications of the specificity data for steroid recognition and complex formation and in vivo control of enzyme activity are discussed.