Estrone Research Articles

Effect of Calcium Soaps of Fatty Acids and Administration of Somatotropin on Milk Production, Preovulatory Follicular Development, and Plasma and Follicular Fluid Lipid Composition in High Yielding Dairy Cows

The effect of fat and bovine somatotropin (bST) on preovulatory follicular hormones and lipids was evaluated by feeding cows for 150 d from parturition a control diet, a control diet plus 0.55 kg/d of calcium soaps of fatty acids, or a control diet with 500mg of bST injected every 14 d. Fourteen days after a synchronized or natural estrus, cows were injected with a PGF2α analogue; 48h later, follicular fluid from all ovarian follicles >8mm was aspirated. Cows fed fat or injected with bST produced more milk and milk solids than did control cows, and cows on the bST treatment lost more body condition after calving than did cows on the other treatments. Both treatments changed the proportion of estradiol-active follicles (>400ng of estradiol/ml of follicular fluid) and the correlation between follicular fluid estradiol concentration and the total number large follicles per cow. In follicles aspirated between 60 and 90 DIM the percentage of estradiol-active follicles was 67, 40, and 0 for cows on the control, calcium soaps of fatty acids, and bST treatments, respectively. After 90 DIM, no differences existed between treatments in the percentage of estradiol-active follicles. Estradiol concentration in follicular fluid was correlated with DIM at follicle aspiration (r=0.51). The proportion of oleic acid in free fatty acids in plasma at 50 DIM was lower in control cows and was lower in follicular fluid of estradiol-active follicles. Both calcium soaps of fatty acids and bST had a considerable effect on follicular development and activity and the composition of fatty acids in follicles.

Egg Yolk Layers Vary in the Concentration of Steroid Hormones in Two Avian Species

Maternally derived steroid hormones are known to be present in the yolks of avian eggs; however, the physiological mechanisms involved in their deposition remain largely unexplored. Investigations of steroid production by avian follicles have demonstrated temporal differences in the concentrations of progesterone, 17β-estradiol, and testosterone during yolk formation. Because yolk is deposited peripherally in concentric spheres as the oocyte develops, differences in the production of follicular hormones during yolk formation should be manifested in differences in the localization of steroids within layers of the yolk. To investigate this hypothesis we analyzed steroid hormone concentrations in layers of individual eggs of the dark-eyed junco (Junco hyemalis) and the red-winged blackbird (Agelaius phoeniceus). We found that in the dark-eyed junco the concentration of progesterone is significantly greater at the periphery of the yolk, while the concentration of 17β-estradiol is significantly greater near the center of the yolk. We also found in both the dark-eyed junco and the red-winged blackbird that the concentration of testosterone remains constant from the interior to the intermediate layers of the yolk and then drops sharply between the intermediate and exterior layers. The patterns of hormone localization that we found agree with those predicted by studies of temporal changes in steroidogenesis in the maturing follicle of the chicken, thus suggesting that within-yolk variation in yolk steroid concentrations in the dark-eyed junco and the red-winged blackbird reflects temporal differences in the pattern of follicular steroidogenesis. Variation in the concentration of hormones among yolk layers presents a methodological concern for studies that involve the removal of yolk samples from viable eggs for subsequent hormonal analysis. This variation also has implications for the timing of embryonic exposure to steroid hormones.

Molecular Modelling of Oestrone Sulphatase Inhibitors

Using molecular modelling techniques, information regarding the active site of oestrone sulphatase was determined. The structural properties of non-steroidal inhibitors required for inhibitory activity against oestrone sulphatase were investigated, and we were able to rationalize the inhibitory activity of both steroidal and non-steroidal inhibitors. The C(17) polar group within the structure of the substrate, oestrone sulphate, was required for potent inhibitory activity. The major requirement of inhibitors appeared to be the mimicking of the steroid C(3) sulphonate group. The phenolic ring in the oestrogen-based inhibitors (and the majority of the non-steroidal inhibitors) was not necessary for inhibitory activity. We synthesized a number of potential non-steroidal straight-chain alcohol-derived inhibitors for biochemical evaluation.

Anaesthesia for assisted conception

Anaesthesia for assisted conception

Abnormal plasma oxytocin and β-endorphin levels in alcoholics after short and long term abstinence

1. 1. Plasma oxytocin (OX), vasopressin (VP), estrone (ES) and β-endorphin (β-end) levels were measured in 13 male non-chirrotic alcoholics, at 1, 4, 7, 15 and 28 days after alcohol withrawal, and only once in 9 sex- and age-matched normal controls. 2. 2. At all examined time points, plasma OX and ES, but not VP, levels were significanlty higher in alcoholics than in controls. Alcoholics showed plasma β-end levels lower than normal. 3. 3. A positive relationship was found between ES and OX levels suggesting that elevated estrogens levels in chronic alcoholics might exert a stimulatory effect on OX. 4. 4. In light of the well-known effect of OX on learnig and memory, an involvement of OX in alcohol-induced neuropsychological deficits may be supposed.

Investigation of oestrogen receptors, sex steroids and soluble adhesion molecules in the progression of malignant melanoma

The question of whether melanoma tumours have classical oestrogen receptors (ERs) is unresolved, but epidemiological data clearly show a survival benefit for female patients with metastatic melanoma. The aims of this study were to examine to what extent the presence of ER in melanoma tumours might relate to disease progression and whether disease progression relates to patients' sex steroid status. Additionally, levels of two soluble adhesion molecules [circulating intercellular adhesion molecule-1 (sICAM-1) and circulating vascular cell adhesion molecule-1 (sVCAM-1)] were examined as independent, possibly prognostic indicators of disease progression. ER immunocytochemical assay identified only two lesions (out of 69 investigated) which had any evidence of the receptors, and staining in these lesions was very modest. No significant changes in oestrone or androstenedione levels were noted for male or female patients with disease progression. As expected, oestradiol levels reflected the menopausal status of the female patients but, for all post-menopausal female patients and male patients, there was no significant relationship to tumour stage. However, a significant decrease in sex hormone-binding globulin occurred with disease progression in male but not female patients, and sex differences in the levels of soluble adhesion molecules were also seen in advanced metastatic disease.

The Hydrogenation and Deuteration of Estrone

Hydrogenation (H2/PdC) of estrone (1) gives estrane-3,17-dione (2), the 5α, 10α A/B ring fusion stereochemistry being established by NMR. Reduction of estrone using D2/PdC gives 1α,2α,4α,5α,6,6,9α,10α-d8-estrane-3,17-dione (3).

Effect of finasteride on human testicular steroidogenesis.

We studied the testicular function and some androgen-mediated events in 22 males (16-30 years of age) with male pattern baldness that was treated with finasteride (10 mg once daily) for 2 years. Patients were evaluated every 3 months. Prostatic volume was determined in six subjects by endorectal ultrasound scans. Serum gonadotropin, prostate-specific antigen (PSA), and sex hormone levels were determined basally and periodically during the treatment period. Fourteen subjects underwent gonadal stimulation with human chorionic gonadotropin (hCG), and the gonadotropin response to gonadotropin releasing hormone (GnRH) was determined in eight subjects, prior to and after 2 years of therapy. Finasteride treatment resulted in an improvement in the male pattern baldness and prostatic shrinkage that was associated with an increase in serum testosterone levels (17.2 +/- 2.5 vs. 26.3 +/- 1.7 nmol/L) and a decrease in dihydrotestosterone (DHT) levels (1.45 +/- 0.41 vs. 0.38 +/- 0.10 nmol/L), causing a marked increase in that testosterone/DHT ratio. A significant increase in the serum levels of androstenedione (3.67 +/- 0.49 vs. 7.05 +/- 0.70 nmol/L) and estradiol (132 +/- 44 vs. 187 +/- 26 pmol/L) was also noted, whereas androstanediol glucoronide (33.3 +/- 6.4 vs. 10.7 +/- 4.5 pmol) and PSA (1.6 +/- 0.6 vs. 0.4 +/- 0.1 ng/ml) were significantly decreased. No changes in basal or stimulated levels of gonadotropin were observed. There was a significant increase in the testosterone response to hCG during finasteride therapy (delta: 16.7 vs. 35.5 nmol/L) that could be explained, at least in part, by the reduction of testosterone metabolism resulting from the blockage induced by finasteride. The decrease in the androstenedione to testosterone and estrone to estradiol ratios observed after hCG treatment, however, strongly suggests increased activity of the 17-ketosteroid reductase enzyme and an improvement of the testicular capacity for testosterone production.

Regulation of aromatase and sulphatase in breast tumour cells.

In situ oestrogen synthesis makes an important contribution to the high oestrogen concentration found in breast tumours. Cytokines, including interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF alpha), have been shown to regulate aromatase activity in fibroblasts derived from normal and malignant breast tissues. In the present study, the ability of other cytokines in the IL-6 superfamily (IL-11 and oncostatin M) to stimulate aromatase activity has been confirmed. Formation of oestrone via the oestrone sulphatase pathway may be the major route of tumour oestrogen synthesis and in the present study TNF alpha was found to stimulate sulphatase activity in a dose-dependent manner. Human serum albumin was also found to be a potent stimulator of oestrone sulphatase activity. Its stimulatory effect was blocked by basic fibroblast growth factor, but not by several other growth factors tested. Insight into the regulation of oestrogen synthesis in breast tumours should enable the development of novel compounds to inhibit oestrogen synthesis in women with breast cancer.

17 beta-hydroxysteroid oxidoreductase activity in intact cells significantly differs from classical enzymology analysis.

This paper summarizes our most recent results of steroid enzyme studies on cultured breast and endometrial cancer cells. It deals mainly with estrogen 17 beta-hydroxysteroid oxidoreductase (17 beta HSOR) activity, which presides over estradiol (E2) and estrone (E1) interconversion, a major metabolic pathway of estrogens. Assessment of either the oxidative or reductive component of 17 beta HSOR was carried out on intact cells by means of an original approach based on reverse phase-high performance liquid chromatography and radioactive detection on line. This system allows the continuous monitoring of both precursor degradation and formation of several radiometabolites to assess rates and direction of steroid metabolism. Overall, hormone-responsive, estrogen receptor (ER)-positive cells, regardless of whether they were derived from breast (MCF7) or endometrial (Ishikawa) tumor tissues, showed a prevalence for reductive metabolism (E1-->E2), whilst oxidative pathways (E2-->E1) were largely dominant in non-responsive, ER-poor mammary (MDA-MB231) and endometrial (HEC-1A) cells. The above estimates of 17 beta HSOR activity were at variance with those obtained using the classical enzymology approach, not only in quantitative terms (being markedly lower using intact cell analysis), but also because the prevalent direction of estrogen metabolism was often reversed. Although striking methodological differences may well account for this discrepancy, intact cell analysis is undoubtedly more similar to the in vivo state than the artificial requirements of classical enzymology procedures.

Quantitative structure-chromatographic retention relationship study of six underivatized equine estrogens

Underivatized estrone (ES), equilin (EQ), equilenin (EQN) and their corresponding 17α-diols 17α-estradiol (ESD), 17α-dihydroequilin (DHEQ) and 17α-dihydroequilenin (DHEQN) were separated by TLC, RP-HPLC and capillary GC. Their dipole moments (μ) and Randić's connectivity indices ( 1 χ) were determined as parameters of importance for the separation. The number of H atoms was taken as an additive structural parameter of importance for the quantitative structure-chromatographic retention relationship study (QSRR). Principal component analysis (PCA) was applied in order to find similarities and dissimilarities between 9 TLC and 10 RP-HPLC systems. PCA indicated that proton donor-proton acceptor interactions play the most important role for the TLC and RP-HPLC separation. The two-dimensional non-linear map of PC variables showed that the keto-estrogens (ES, EQ and EQN) and the corresponding diols (ESD, DHEQ and DHEQN) form two separate clusters. The relationship between GC retention of equine estrogens characterized by Kováts indices (KI), their 1 χ and μ was expressed by the equation KI/100 = a/ 1 χ+ b/ μ 2+ c. The biological activity of the estrogens was related to log 1/μ 2.

Ovarian follicular development and the follicular fluid hormones and growth factors in normal women of advanced reproductive age.

Reproductive aging in women (a physiological decline in the function of the hypothalamic-pituitary-ovarian axis) is an infrequently investigated and poorly understood biological phenomenon. Although menstrual irregularity and anovulation are known to precede the menopause, normal women in their fifth decade experience a profound decrease in fertility while still experiencing regular menstrual cycles. To further our understanding of the physiological changes associated with reproductive aging, this study examined the spontaneous development and function of ovarian follicles in normal women, aged 40-45 yr. The subjects were women (n = 21), aged 40-45 yr, who had regular 25- to 35-day ovulatory menstrual cycles, were not infertile, had no medical problems, and met specific criteria for weight, diet, and exercise. The controls were normal women (n = 20), age 20-25 yr, who met the same criteria. The subjects were monitored with daily hormone measurements [LH, FSH, estradiol (E), progesterone (P), and inhibin] and pelvic sonograms from day 1 of their study cycle until the dominant ovarian follicle reached a mean diameter of 15 mm and/or a serum E level of 550 pmol/L or higher was attained. At that time, 10,000 U hCG were given, and a transvaginal sonographic follicle aspiration was performed 32 h later. The follicular fluid (FF) was collected, stored frozen at -70 C, and later analyzed for E, P, testosterone (T), androstenedione, inhibin, insulin-like growth factor I (IGF-I), and IGF-II. The number of cycle days to aspiration was lower (11.6 vs. 15.6 days; P < 0.001) and the early follicular phase mean FSH and mean E levels were higher (9.3 vs. 6.6 mIU/mL and 305 vs. 160 pmol/L; P < 0.01) in the older (O) group compared to the younger group. There was a strong trend toward higher FF mean E (2280 vs. 1931 nmol/L) and lower FF mean T (978 vs. 2361 pmol/L) levels in group O. The E/T ratio was significantly higher (5253 vs. 2408; P < 0.03) in group O. In group O, the mean FF P levels were increased as well (25.1 vs. 18.8 micromol/L; P < 0.01). The serum mean IGF-I (153 vs. 226 ng/mL; P < 0.001) and FF mean IGF-I (113 vs. 158 ng/mL; P < 0.02) levels were significantly decreased in group O. There were no differences between groups in serum or FF IGF-II or inhibin levels. Whether reproductive aging is an intrinsic ovarian process or the ovary is simply responding to exogenous influences, the ovary in general and its follicles in particular are the primary site of the effects of aging. Ovarian follicles in older ovulatory women have some unique features: 1) the follicles are the same size as those in younger women, but form more rapidly; 2) secretion of E and inhibin is not compromised; 3) the concentrations of steroids in the FF are indicative of a healthier follicle, i.e. increased P levels and higher estrogen to androgen ratio; and 4) serum and FF levels of IGF-I are decreased, but there are no differences in IGF-II levels.

Some Flavones and Isoflavones as Inhibitors of Human Placental 17β‐Hydroxysteroid Dehydrogenase In‐vitro

Oestrogen-dependent breast cancers are considered to produce oestradiol in the breast through the initial action of a sulphatase on the oestrone sulphate reservoir, followed by reduction of the oestrone formed by a 17β-hydroxysteroid dehydrogenase. The low rate of incidence of the disease in the Far East has been related to a high dietary intake of soya products containing flavones and isoflavones. We have found that the flavones chrysin (IC50 60-5 μM), apigenin (18-3 μM) and naringenin (19-9 μM), and the isoflavones genistein (195 μM), biochanin A (47-6 μM) and daidzein are potent inhibitors of human placental 17 β-hydroxy steroid dehydrogenase.

Activation of the human estrogen receptor by estrogenic and antiestrogenic compounds in Saccharomyces cerevisiae: a positive selection system

The yeast URA3 gene was used as a reporter to investigate the activities of estrogenic and antiestrogenic compounds in yeast Saccharomyces cerevisiae. The control sequences of the wild type (wt) URA3 promoter were replaced with zero, two, or six copies of estrogen-response elements (ERE). Insertion of two and six copies of ERE rendered the expression of the URA3 gene to be dependent on the presence of the human estrogen receptor (ER) and the hormone 17β-estradiol (E 2). Two versions of the ER genes were constructed: a full-length wild-type ER (ERa-f) and a truncated ER with domains C, D, and E (ERcde). Both forms of the ER were able to activate the ERE-URA3 reporter in a hormone-dependent manner. The growth of yeast transformants were hormone-dependent when the reporter constructs were inserted into chromosomes using yeast integrating vectors (YIp) but not with the 2μ-based episomal (high-copy number, YEp) or centromeric (low-copy number, YCp) vectors. The integrated transformants were employed to investigate the effects of estrogenic and antiestrogenic compounds. The estrogenic compounds, E 2, diethylstilbestrol (DES), and estrone (EST), activated expression of the reporter genes at 1 nM concentration, which is the same concentration exhibiting activity in mammalian cells. None of the antiestrogens, at concentrations up to 1 μM, including tamoxifen (TAM), raloxifene (RAL), and ICI 164,384 (ICI) antagonized 1 nM of E 2 against either form of the ER. In fact, TAM, RAL, and ICI displayed slight agonistic activity at high concentrations of 300 nM or greater to the ERcde. This system can be used to investigate or clone the missing factor(s) that is responsible for the antagonistic activity of the ER in yeast, and is also suitable for screening for the effectors of the ER.

Pituitary-ovarian dysfunction as a cause for endometriosis-associated and unexplained infertility.

This study examines circulating and follicular hormone concentrations and fertilization of oocytes in cycles totally unperturbed by exogenous gonadotrophins in 10 women (25 cycles) with untreated minimal-mild endometriosis and nine women (23 cycles) with prolonged unexplained infertility compared with 16 women (50 cycles) with tubal damage as functional controls. Endometriosis was associated with a significantly longer follicular phase (median 15, 12, 13 days respectively) and reduced oestrogen secretion (median index area under the curve 3063, 3842, 3805 units respectively) compared with controls. Both endometriosis and unexplained infertility had significantly reduced serum luteinizing hormone (LH) surges [median peak serum (LH) 43, 39, 55 IU/l respectively and median area under the curve 661, 687, 823 units respectively] and reduced LH concentrations in follicular fluid (median 19.6, 10.6, 9.2 IU/l respectively). These findings suggest that infertility associated with minor endometriosis and of apparently unexplained aetiology share a common pathophysiology in impaired LH surge secretion. Whether that represents a primary pituitary disorder or is secondary to a defective ovarian signal is discussed.

Impact of different gonadotropin and GnRH agonist regimens on serum and follicular fluid hormone levels and folliculogenesis

Gonadotropin-releasing hormone agonists (GnRH-a) are currently used in virtually every assisted reproduction ovulation induction cycle to reduce cancellation rates and to improve treatment outcome. The combination of GnRH-a and gonadotropins appears to be safe and devoid of direct side-effects even when GnRH-a are administered in early pregnancy. We recently showed that long GnRH-a regimens are preferable to short (flare-up) regimens as they result in a greater follicle yield and a better intrafollicular endocrine environment. Thus, the combined use of long GnRH-a regimens and gonadotropins for assisted reproduction ovulation induction is destined to further grow.

Ovarielle Stimulation mit verschiedenen FSH/LH-Konzentrationen in einem In-vitro-Fertilisationsprogramm

Various stimulation regimes have been tried to induce multiple follicular development for in-vitro fertilisation and embryo transfer. Human menopausal gonadotrophins have been widely used to induce follicular growth. To evaluate the role of the FSH: LH-ratio and the importance of LH concentrations, the results of a randomised assessor-blind group comparative efficacy and safety study are described. The effects of preparations, comprising FSH: LH-ratio of 3:1 and FSH: LH-ratio of 1:1 respectively, in stimulation of the ovaries for in-vitro fertilisation in infertile women are compared. Patients under 38 years of age with regular menstrual cycle (27 +/- 3 days and 32 +/- 3 days) are included. Sperm parameters have to be in normal range, according to WHO criteria. Follicular and luteal hormone parameters, ultrasound measurements, oocyte quality, fertilisation, cleavage and pregnancy rates are reported. The outcome of in-vitro fertilisation after the administration of preparations containing different ratios of FSH:LH leads to comparable results. However, the rate of ovarian hyperstimulation syndrome and the abortion rate after embryo transfer seems to be lower in patients stimulated with FSH dominant gonadotrophins.

Purification and Properties of Steroid Sulfotransferase in Human Fetal Liver

Steroids in fetal circulation are known to exist in a sulfoconjugated form. To investigate the contribution of human fetal liver to the sulfoconjugation of steroids, and the properties of steroid sulfotransferase, an attempt was made to separate the specific sulfotransferases toward estrone (E-ST) and 3β-hydroxysteroid (3β-ST). For the purification procedure, successive chromatography was used:(1) DEAE-Sepharose CL-6B chromatography (2) Chromatofocusing and (3) Adenosine 3', 5'-diphosphateagarose affinity chromatography. Enzymatic activity was obtained with 3H-estrone (E1), 3H-pregnenolone (P) and 3H-dehydroepiandrosterone (DHA) as substrates. Two active fractions of steroid sulfotransferase were collected from the eluate of a CL-6B column. Fractions 88-120 found to be specific for E1, were purified approximately 1, 800 fold by further chromatographic procedures. The affinity column condition used was set at pH 7.2. The apparent Km and Vmax values were 1.66 μM and 35.6 nmol/mg protein/min, respectively. Fractions 130-162 specific for P were further purified approximately 144 fold. The affinity column condition used was set at pH 6.0. The apparent Km and Vmax values were 0.25 μM and 4.36 nmol/mg protein/min, respectively. Both enzymes were found to be a single band and had almost the same molecular weight of approximately 36 kDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Both enzymes equally catalyzed DHA to form DHA-sulfate. In the present study, E-ST and 3β-ST were separated and purified in human fetal liver for the first time, with kinetic analysis for both enzymes.

Cumulus and oocyte maturation and in vitro and in vivo fertilization of oocytes in relation to follicular steroids, prolactin, and glycosaminoglycans throughout the estrous period in superovulated heifers with a normal LH surge, no detectable LH surge, and progestin inhibition of LH surge

Crossbred heifers (n = 103) were synchronized to estrus with prostaglandin (PGF 2α) and superovulated with follicle stimulating hormone (FSH-P). Animals were ovariectomized every 12 hr after the PGF 2α injection ( n = 7 to 9/ time) up to 108 hr to monitor the follicular, hormonal, and oocyte changes associated with follicular development and ovulation. Twenty-eight animals were implanted with Norgestomet implants 12 hr before PGF 2α and ovariectomized at 72, 84, 96, and 108 hr post PGF 2α injection to monitor effects of progesterone and suppression of the luteinizing hormone (LH) surge on oocyte maturation and quality. Follicular fluid was collected and analyzed for progesterone, estradiol, prolactin, and glycosaminoglycan content in conjunction with cumulus maturation and nuclear stage of oocyte maturation. Analysis of in vivo matured oocytes by in vitro fertilization was carried out at 60, 72, 84, and 96 hr post PGF 2α and in vitro matured oocytes at 12 to 108 hr post PGF 2α. No developmental changes in cumulus cells surrounding the oocyte of small follicles was noted (≤ 4 mm dia) indicating a static population. Medium (> 4 ≤ 8 mm) and large size (> 8 mm) follicles developed to the corona radiata and loose cumulus stages in animals in which an LH surge was detected but cumulus status remained primarily in the tight cumulus stage for animals without an LH surge. The estradiol-to-progesterone ratio for tight cumulus (TC), corona radiata (CR), and loose cumulus (LC) stages was 1.8 ± .1, 1.0 ± .1, and .4 ± .2, respectively (P < .01). Nuclear maturation of oocytes in small follicles from animals without a detectable LH surge seem to indicate early maturation (48 to 72 hr post PGF 2α) in conjunction with a high percent of degenerate oocytes not seen in animals exhibiting an LH surge. Oocytes from medium size follicles matured to germinal vesicle breakdown (GVBD) and early meiosis (metaphase I; MI) stages of development in all treatments. Most oocytes were degenerate in Norgestomet-implanted animals. Oocytes from large follicles (> 8 mm dia) from animals exhibiting an LH surge were in MI and metaphase II (MII) stages (48 to 84 hr post PGF 2α) in preparation of ovulation whereas oocytes from animals not exhibiting an LH surge had oocytes that early matured to MII (48 to 72 hr post PGF 2α), later regressing to degenerate oocytes (84 to 108 hr). Follicular progesterone, estradiol, and prolactin increased with oocyte maturation, particularly in medium and large follicles. In vivo matured oocytes for fertilization (60, 72, 84, and 96 hr post PGF 2α) were nude (from the oviduct) and primarily CR from follicles. Tubal oocytes (37%) were fertilized more frequently by a single sperm than follicular oocytes (14.3%; P < .01) and single sperm penetration peaked at 72 hr post PGF 2α. Follicular hormone concentrations were not related to sperm penetration. Oocytes (n = 101) matured in vivo had lower fertilization potential from ovaries producing < 14 or > 50 follicles (39.3%) as compared to 21 to 45 aspirated follicles (68.2%; P < .05), with a peak penetration at 32 follicles (86.7% penetration). No treatment differences (LH surge or no detectable LH surge) were noted in relation to in vivo matured oocytes. Oocytes with single sperm penetration had the lowest estradiol/progesterone ratio of 2.2 vs polyspermic penetration of 13.7.

The production of monoclonal antibody to androstenedione and the effect of passive immunization on Xinjiang fine-wool sheep with it.

Five hybridomas stably secreting monoclonal antibodies (McAbs) to androstenedione were prepared by using artificially synthesized androstenedion-11 alpha-succinyl conjugate with bovine serum albumin (BSA) as antigen. These McAbs showed slightly high cross-reactivity with testosterone (8.1-12.3%) and estrone (0.8-2.5%) and high affinities ranging from 2.0 x 10(7) to 2.8 x 10(8) L/M. They were all of the IgG1 subclass. Xinjiang finewool ewes which were passively immunized with McAbs had higher circulating levels of progesterone (P) and luteinizing hormone (LH) than those of control ewes in two oestrous cycles and these changes led to increased ovulation rate and twin lambs born in young ewes.