Effects Of Estradiol Benzoate Research Articles

Effect of oestradiol benzoate on biliary phospholipids in the rat.

Bile was collected from conscious, ovariectomized, young female rats which had been treated with either oestradiol benzoate or peanut oil for 3 weeks. L-[Me-14C]Methionine was given intravenously immediately before collection of bile was started.

Effect of actinomycin D on estrogen-induced release of luteinizing hormone in ovariectomized rats.

Ovariectomized rats were injected with 0.5 μg/day of estradiol benzoate (EB) for 6 days. On day 7, at 1100 hr, they were given 50 μg EB or oil. They were sacrificed at 1600 hr either on day 7 or 8, and LH levels in the serum were determined by radioimmunoassay. In animals killed on day 7, LH levels of EB and oil treated rats did not differ significantly, but in those killed on day 8, EB treated rats had significantly higher levels of LH than oil treated rats. Injection of 80 μg/100 g bw of actinomycin D (AD) at 0700 hr, 4 hr prior to 50 μg oil or EB, had no detectable effect on LH levels in animals killed on day 7, but blocked the effect of EB on LH levels in animals killed on day 8. When AD was given at 0700 on day 8, it did not alter the effect of EB on LH levels in animals killed 9 hr later. AD had no observable effect on LH levels in the oil treated controls. These results suggest that the induction of LH release by EB may require DNA dependent m-RNA synthesis within 0-20 hr after the injection of EB....

The Effects of Estrogen and Progesterone on the Blood Levels of Glucose, Non-Esterified Fatty Acids and Cholesterol in Ovariectomized Sheep

The effects of estrogen and progesterone on the blood levels of glucose, non-esterified fatty acids and cholesterol in ovariectomized sheep. The effects of estradiol benzoate and progesterone on blood glucose, NEFA and cholesterol were studied in ovariectomized sheep. Intramuscular injection of 2.5 mg estradiol benzoate gave biphasic changes in NEFA. After 2 hrs. NEFA was decreased, but thereafter an increase occurred and maximum levels were reached after 24 hrs. Blood glucose was significantly increased from 12 to 48 hrs. after the injection. Serum cholesterol was lowered after 24 hrs., but thereafter the level increased. Maximum values were obtained after 120 hrs. Progesterone at the same dose did not change any of the measured parameters. Simultaneous administration of estradiol benzoate and progesterone gave similar responses as estradiol benzoate alone. Blood glucose and NEFA were followed during heat in a lactating cow. Both parameters increased after ovulation. Since NEFA was increased during so long time after the injection of estradiol benzoate, the mechanism behind this effect was discussed. No lipolytic hormone has been reported to give a response of this duration. Estrogen is known to increase plasma GH, and since GH is strongly lipolytic in sheep it seemed possible that the elevated NEFA levels were caused by increased GH secretion. There is now evidence that also estrogen-induced changes in serum cholesterol are pituitary dependant. It was therefore considered possible that all the noted metabolic changes were mediated by the pituitary.

Effect of oestrogen and progesterone on the release of luteinizing hormone in pseudopregnant rats.

ABSTRACT The administration of 20 μg oestradiol benzoate to rats on the 4th day of pseudopregnancy caused a rise in serum luteinizing (LH) concentration on the following day. This effect of oestradiol benzoate was reduced when the animals were ovariectomized at the time of the steroid injection. The response was restored by injection of progesterone with oestradiol benzoate thus showing the importance of progesterone for the mechanisms which trigger off the release of LH.

Direct Inhibition by Ergocornine of Pituitary Prolactin Release

The effects of ergocornine, estradiol benzoate (EB) or both on anterior pituitary (AP) and serum prolactin concentrations were studied in ovariectomized or hypophysectomized rats with a pituitary transplant, and directly on the AP in vitro. Injections of 5 or 10 μg EB into ovariectomized rats for 5 days produced 3-to 4-fold increase in AP prolactin concentration, a 6-to 8-fold rise in serum prolactin and increases in pituitary weight and mammary growth. Doses of 0.1 or 0.3 mg ergocornine methanesulfonate (ERG) partially or completely inhibited the stimulatory effects of EB on each of these parameters. Transplantation of one AP into the kidney capsule of hypophysectomizedovariectomized rats resulted in relatively high blood prolactin levels. ERG reduced prolactin release from the AP graft and mammary growth, whereas EB increased both AP and serum prolactin concentrations and mammary growth. When given together, ERG partially counteracted EB stimulation of pituitary and serum prolactin levels and mammary gr...

Release of Luteinizing Hormone Induced by Estrogen Injection Into Ovariectomized Rats

The effect of estrogen on the release of luteinizing hormone (LH) and folliclestimulating hormone (FSH) was studied in spayed rats. The concentration of the hormones in serum was determined by a radioimmunoassay procedure. After a single injection of 20 μg estradiol benzoate (EB), the elevated values of LH in ovariectomized rats were reduced the following day and remained low for at least 8 days. A second injection of EB given at noon 3 or 4 days after the first injection significantly increased serum LH a few hours later and a second peak of LH also occurred the next day. When EB was injected on alternate days, beginning 3 days after the priming dose, high serum LH levels were found every day up to the eighth day. The positive feedback effect of EB on LH release was observed only in the afternoon and not in the morning. No significant changes in serum FSH were found. It is concluded that estrogen injection is effective in triggering the release of LH in ovariectomized rats primed with estrogen. (Endocrin...

Mechanism of stimulatory feedback effect of estradiol benzoate on the pituitary.

Experiments were conducted to investigate the mechanism whereby intrapituitary implantation of crystalline estradiol benzoate (EB) on diestrus-2 advances ovulation by 1 day in rats showing 5-day estrous cycles; or 4- day rats converted to a 5-day cycle by progesterone on metestrus (diestrus-1). Sodium pentobarbital early in the afternoon of the day following implantation prevented advancement of ovulation. It was restored in 50% of animals after administration of a submaximal dose of an ovine gonadotropin releasing factor preparation. To determine the required period of action of estrogen on the pituitary, implants were allowed to remain in situ for different periods of time at different stages of the cycle. Twenty-four hr implantation from the morning of diestrus-2 was effective, in contrast to similar implantation 1 day later. When implants were placed for shorter periods of time on diestrus-2, it was found that implantation from 1 to 5 PM advanced ovulation in all of 9 rats tested. This period of expos...

Effect of estrogen and anti-estrogen on reproductive function in neonatally androgenized female rats.

Estradiol benzoate (EB) and ethamoxytriphetol (MER-25)2 were administered during puberty in an attempt to influence time of occurrence of the anovulatory syndrome and degree of receptivity in neonatally androgenized rats. When 5 days old, Sprague-Dawley female rats were injected with either oil or 3, 5, 10 or 50 tig testosterone propionate (TP) and, when 26 days old, with either 20 μg EB for 5 or 10 successive days or 5.0 mg MER-25 or oil for 10 days. All subjects were ovariectomized between 81 and 90 days of age and after 1 week received the first of 3 weekly receptivity tests with vigorous males. Heat was induced by injecting 10 μg EB followed 44 hr later by 0.5 mg progesterone. For the most part, the effect of EB and MER-25 on age of vaginal opening was independent of neonatal androgen treatment. EB advanced by approximately 5 days and MER-25 delayed by 6 days onset time of vaginal canalization. Age of onset of persistent vaginal estrus (PVE) was inversely related to neonatal TP dosage. EB increased by...

Effect of Timing and Quantity of Estrogen on Gonadotrophin-Induced Ovulation in Immature Rats

Induction of ovulation in immature rats by pregnant mare's serum (PMS) is initiated by the secretion of ovarian hormones; these exert a positive feedback stimulus on the hypothalamo-pituitary complex, which, in turn, releases the gonadotrophins necessary to bring about ovulation. When PMS is given at 9 am on the 28th day of age, spontaneous ovulation follows on day 31. A single injection of 0.5 μg of estradiol benzoate (EB) at 9 am on day 30 facilitated PMS-induced ovulation, whereas earlier treatment (9 am on day 28) or later treatment (3 or 7 pm on day 30) was less effective. Either more or less estrogen given at 9 am on day 30 also proved less effective; 4 μg suppressed ovulation entirely, as did 3 daily injections of 0.5 or 1.0 μg of EB (days 28 through 30). However, if animals were treated with 0.5 μg of EB on days 28 and 29 and with 1 μg EB or 1 mg progesterone at 9 am on day 30, ovulation occurred on the following day. Experiments with HCG failed to show any direct inhibitory effect of EB on the ov...

Effects of estrogen, SU-9055, and cyproterone acetate on the hypersecretory activity in the seminal vesicles of the castrate catfish, Heteropneustes fossilis (Bloch).

AbstractThe effect of estradiol benzoate (EB), SU‐9055, and cyproterone acetate (CA) on the hypersecretory seminal vesicles of the castrate catfish has been studied. EB to a marked extent, SU‐9055 and CA to a lesser extent inhibit castration induced hypersecretion in the seminal vesicles. This implies that while EB inhibits the gonadotrophin production, SU‐9055 and CA act at the level of the interrenal glands and the seminal vesicles respectively. The data indicate that following castration the high level of circulating gonadotrophin induces the interrenals to produce androgens which in turn bring about hypersecretion in the seminal vesicles.

Effect of estradiol benzoate, human chorionic gonadotropin, and follicle-stimulating hormone on unilateral ovariectomy-induced compensatory hypertrophy in Catfish, Heteropneustes fossilis (Bloch)

Studies on the compensatory hypertrophy response of the catfish ovary after unilateral ovariectomy during the spawning season indicate that the remaining ovary has the ability to compensate for the loss of its counterpart, gravimetrically as well as in the number of oocytes, within 15 to 22 days. This system was used to study the effect of administration of estradiol benzoate (EB), follicle-stimulating hormone (FSH), and human chorionic gonadotropin (HCG) alone or in combination on hemiovariectomy-induced ovarian compensatory hypertrophy. Administration of high dose of EB effectively blocked ovarian compensatory hypertrophy whereas a low dose was only partially effective. HCG when administered alone accentuated the compensatory hypertrophy response of the ovary in terms of increase in the number of oocytes. HCG when administered along with EB counteracted the inhibitory effects of EB. FSH on the contrary, did not have any stimulatory effect on ovarian compensatory hypertrophy. The significance of these findings is discussed.

Effect of anti-estrogen on steroid induced sexual receptivity in ovariectomized rats

Ovariectomized female rats were injected with estradiol benzoate (EB) and 48 hr later with progesterone, in order to induce sexual receptivity as measured by the lordosis quotient (LQ) over 30 mounts. The antiestrogen CN-55, 945-27 (CN) markedly reduced the LQ when administered by gavage at the time of EB injection. There was no effect of CN when given at the time of progesterone injection, nor when given 24 hr after EB. These data demonstrate that CN counteracts the behavioral effects of EB, and suggest that exposure of the brain to EB for less than 24 hr is sufficient to trigger processes which culminate in the lordosis response of the female rat to the male.

Comparative Effects of Steroids on Skin Maintained in Organ Culture. II. Estradiol, Progesterone, and Testosterone2

Full-thickness, auricular skin from adult mice was maintained in organ culture for 1–5 weeks. The effects of estradiol benzoate, testosterone, and progesterone incorporated in the culture medium were studied, and the ability of skin to function as an autograft after treatment with these steroids was compared. The gross and microscopic changes produced by these compounds were studied. Wet and dry weights were compared for the skin maintained for different lengths of time with, the steroids added to the medium. Skin treated with progesterone functioned successfully as autografts after up to 5 weeks in organ culture. Testosterone obtained results essentially similar to those previously reported for cortisone. Estradiol, on the other hand, somewhat reduced the time the tissue could be held in vitro and still function as an autograft. In addition, it enhanced the loss of the architectural integrity of the skin in vitro. Progesterone and, to a lesser extent, testosterone protected the normal histologic features of the cultured skin. The significance of these results in terms of the dichotomy of structural integrity and functional ability is discussed.

Effect of estradiol benzoate on lipid metabolism in the rat.

The effect of estradiol benzoate on the concentration of lipids in the plasma, liver and heart and on the incorporation of acetate 1-14C into lipids in these tissues has been studied in adult male rats. Following the daily injection of 1.7 mg of estradiol benzoate for 5 days, estrogen- treated and control animals were injected with 14 μc of sodium acetate 1-14C and killed 2, 4, 12, 24, 48 and 60 hr after the injection. There was a marked decrease in plasma free and esterified cholesterol, plasma phospholipids and the plasma cholesterol/phospholipid (C/P) ratio. The accompanying increase in liver cholesterol ester suggests that estradiol benzoate causes the transfer of cholesterol ester from the plasma to the liver. The increased turnover rate of plasma free cholesterol but lack of increase in liver free cholesterol may be due to an influx of free cholesterol from the plasma to the liver, the effect of which is balanced by a decreased rate of hepatic free cholesterol synthesis. There was a decreased incorporation of acetate 1-14C into liver cholesterolcholesterol ester and free cholesterol. In the plasma cholesterol ester fractions of the estrogen-treated animals there was an increase in the percentage of cholesterol oleate. The decrease in plasma phospholipids was not reflected by significant changes in corresponding liver or myocardial tissue fractions. Estradiol benzoate had no apparent effect on the concentration of tri- and diglycerides in the tissues examined but decreased the plasma monoglyceride and the liver free fatty acid (FFA) concentrations. The incorporation of acetate 1-14C into the plasma FFA was decreased in the estrogen-treated animals. There was also a decreased incorporation of the acetate 1-14C into the plasma triglycerides and the FFA liver tri-, di- and monoglycerides and phospholipids. The specific activity values for myocardial tissue were too low to determine whether estradiol benzoate might have any effect on the lipids in this tissue. There was no apparent effect on myocardial lipid concentrations. (Endocrinology80: 263, 1967)

Relationship between male reproductive function and estrogen. VI. Effect of estradiol benzoate on the secretion of accessory sex glands in the bull

1.正常牛にestradiol 6mg30日間投与した場合の精液性状は,DESを投与した時と全く同じように精液量の減少,精子活力の減弱,精子数の軽度の減少,奇形率の増加(主としてlooped tail)などの所見が得られた。また精漿の交換試験では明らかに正常精子の運動性を減弱させた。2.精管結紮牛にestradiolを1~2mg連日7日間投与して採取した精漿の性状は,投与期間が短かいために影響は軽度であったが,2mg投与では射精量の減少,精液緩衝能力の低下を認め,本牛精漿を添加した正常精子の生存性は低下した。3.去勢牛に試験期間50~100mgのtestosteroneを隔日に注射し,これにestradiolを5~10mg連日7~10日間投与し,1日のE:Tが1:2.5~1:10の割合になるようにした場合の精漿も前記同様,pHはアルカリ性に強く傾き,緩衝能力の減弱,果糖量の減少などが認められた。精漿の交換試験においてもEd投与未期および中止後の精漿は精子に対して阻害作用を呈した。4.これらの雄牛の精漿中無機質の濃度は,estradiolの投与によってNaの増加,Kの減少,Clは正常牛は減少,他は増加,Caについては正常牛は増加したが,他は著変がみられなかった。5.試験終了時に解剖して採取した副性器の組織所見では,末期testosteroneのみ投与のNo.3と,estradiolのみ投与のNo.4の問に若干の差が認められ,estrogenの影響が強かったNo.4では,前立腺部尿道のえ死,分泌物充満,尿道球腺の腺胞および排泄管内腔の分泌増加などの所見が得られた。以上のことからestragenが精巣における精子形成障害を起す以前のかなり早期に,副生殖腺の分泌物の性状に異常を誘起し,それが生産された精子に対して悪影響をおよぼすものと考える。

Effect of estradiol benzoate on cholesterol and vitamin A metabolism.

SummaryWeanling male rats depleted of their liver vit. A stores were given the following for 21 days: 0.5% or no cholesterol, 150 or 1000 IU of vit. A acetate daily, and subcutaneous injections of 4 μg of estradiol benzoate 3 times a week in 0.1 ml of cottonseed oil or the carrier oil only. One-half of the rats were castrated at about 4 weeks of age. Castrates showed an inverse relationship between liver vit. A and cholesterol deposition. Estrogenic-treated castrates fed cholesterol responded like the intact rats with an inverse relationship between liver cholesterol deposition in dietary vit. A level. Estradiol benzoate 1) depressed the cholesterol/liver content in the intact rats fed cholesterol and the castrates fed cholesterol with the high vit. A level which may be a reflection of the effect of EB on liver weight only; 2) increased the liver vit. A concentration in castrates fed cholesterol and in intact rats fed cholesterol and the high vit. A level; 3) increased the serum cholesterol level in all g...

CONNECTIVE TISSUE 13. EFFECT OF ESTRADIOL BENZOATE UPON COLLAGEN SYNTHESIS BY SPONGE BIOPSY CONNECTIVE TISSUE.

Summary1. The effect of estradiol benzoate upon collagen synthesis in sponge biopsy connective tissue has been studied in normal and ovariectomized rats. 2. A dose of 300 μg, twice weekly for 4 weeks, produced a decrease in sponge weight, collagen concentration and total amount of collagen. However, the radioisotopic data demonstrated a stimulating effect of estrogen on collagen synthesis, as there was an increase in the specific activity of collagen, hydroxylysine and lysine and the total counts per minute recovered per incubation. These results lead to the conclusion that estradiol stimulates the metabolism of collagen. 3. The stimulatory effect of estradiol on collagen synthesis in sponge biopsy connective tissue is more readily demonstrated in the ovariectomized than in the intact rat.

GONADAL ACTIVITY AND SEXUAL DIFFERENTIATION OF THE HYPOTHALAMUS.

The administration of testosterone propionate (TP) or estradiol benzoate (EB) to the neonatal female rat induces masculinization of the hypothalamus and results in a tonic pattern of gonadotropin (GTH) secretion and the absence of ovulation. To determine the relation between this effect of steroids on the developing hypothalamus and endogenous gonadal activity, newborn rats were subjected to gonadectomy and/or steroid injection, or gonadal transplantation. The mode of GTH secretion of the host was ascertained by examining the histology of subcutaneous ovarian grafts. Corpora lutea (CL) in such grafts were considered as evidence of the cyclic release of GTH, and their absence as evidence of the tonic or masculine mode of GTH secretion. CL were found in ovarian grafts removed from females ovariectomized on day 2 or 6 of age, and from males castrated on day 2 or 3, some of which received ovarian grafts at the time of castration. CL were absent in grafts removed either from neonatally ovariectomized females given testicular grafts or a single injection of microgram dosages of sex steroids, or from males castrated after 3 days of age. The female pattern of GTH secretion, which is established following castration of the 2-day-old male, did not develop following the administration of 10 μg TP or 5 μg EB at 4 days of age. The results of this study suggest that sexual differentiation of the hypothalamic regulation of GTH secretion is determined by testicular androgen, that this process is independent of normal ovarian activity, and that the masculinizing effect of EB in both male and female rats is not physiologic. The similar response of male and female rats to steroid hormones supports the hypothesis that sexual differentiation of neuronal elements may determine the capacity of the preoptic hypothalamus to regulate the cyclic discharge of GTH. (Endocrinology76: 226, 1965)

Some effects of estradiol benzoate on development of the reproductive system of the turkey

Some effects of estradiol benzoate on development of the reproductive system of the turkey

Inhibition of Estradiol-Induced Endosteal-Bone Formation After Intrafemoral Implantation of Testosterone Propionate Into Mice

1. One hundred and sixty-seven mice had cavities drilled into their right femora and were divided into seven groups with or without intrafemoral placement of hormones or placebos. 2. Mice which had cavities drilled only into their femora or had cholesterol placebos or testosterone propionate pellets implanted intrafemorally showed little endosteal bone proliferation in the distal metaphyses and callus formation at the drilled sites four weeks after implantation. 3. Both intrafemoral and systemic applications of ninety micrograms of estradiolbenzoate induced localized hyperostosis in the traumatized regions. However, four weeks after hormone implantation the distal metaphyses of both femora were endosteally proliferated to approximately the same degree, due to the systemic effects of estradiol benzoate. 4. Over eighty micrograms of intrafemorally placed testosterone propionate was needed to inhibit the effects produced by ninety-microgram pellets of estradiol benzoate placed subcutaneously. However, the androgen inhibited the estrogenic activity not only in the drilled femur, but also in the contralateral one. 5. No sexual differences were observed in response to the dosages of hormones given. Differences in femoral changes between castrated and non-castrated mice were not seen.