Single Injection Of Estradiol Research Articles

Effects of ovarian hormones upon nucleolar ultrastructure in endometrial stromal cells of the rat.

The ultrastructure of the nucleoli of endometrial stromal cells was studied in rats deprived of endogenous steroid hormones by combined ovariectomy and adrenalectomy, and after various hormonal treatments. Three weeks after the operation the nucleoli were small and compact, and composed exclusively of the fibrous component. Administration of progesterone (5 mg/rat im for 7 days) brought about enlargement of the nucleoli and massive accumulation of the granular component; this was attended by augmentation of the rough-surfaced endoplasmic reticulum and of free ribosome clusters in the cytoplasm. Subsequent administration of a single injection of estradiol (0.2 µg/rat, im) caused intensification of these changes. A single injection of estradiol on its own (0.2 µg/rat im) caused the appearance of a small amount of the granular component, but was unable to restore full nucleolar function. It is suggested that progesterone promotes the elaboration of ribosomal precursors by the nucleoli of stromal cells, and that this effect may contribute to the sensitization of this cell type to the action of estradiol.

Effects of estrogen treatment on plasma renin parameters in the rat.

The effects of estrogen treatment upon plasma renin parameters were determined in groups of male rats 1, 6, and 12 hr after administration of a single injection of 100 μg ethinylestradiol, and after more prolonged treatment for 2 and 5 days with 100 μg ethinyl—estradiol daily. In the latter groups, the response to furosemide administration was also evaluated. Measurements of plasma renin activity (PRA), plasma renin concentration (PRC) and renin substrate (PRS) were performed by radioimmunoassay of angiotensin I generated in plasma incubated alone (PRA), with an excess of rat renin substrate (PRC) and with an excess of rat renin (PRS). The most notable result of these experiments was the rapid onset of the estrogen—induced rise in circulating renin substrate, which was significantly elevated as early as 6 hr after a single injection of estradiol. This rise was accompanied by an early increase in PRA, which remained elevated for 2 days during continued estrogen treatment and fell to slightly below normal l...

Induction of phosvitin by oestradiol in rooster liver needs DNA synthesis.

THE synthesis of an egg yolk protein phosvitin, which is normally synthesized by the laying hen, can be induced in immature pullets1 or roosters2 by treatment with oestrogens. Phosvitin appears in the plasma of roosters with a lag period of 24 h after a single injection of oestradiol, reaching maximum values at 72 h3. The lag period is reduced on sequential injections of the hormone. The peak values of the protein in plasma as well as total amounts synthesized are enhanced progressively with successive exposures to the hormone3. The livers of hormone-treated birds become larger4,5. These observations suggested that the amplified response to sequential injections of the hormone could be due to more cells that synthesize the protein being mobilized. Our experiments suggest that DNA synthesis is necessary before the target cells can be stimulated to synthesize phosvitin by oestrogens.

Reproduction and estrogen-induced vitellogenesis in Dipsosaurus dorsalis

1. 1. The ovarian cycle of female Dipsosaurus dorsalis was studied during June through October. A peak of vitellogenesis occurred in late June. 2. 2. Ovarian maturation was accompanied by significant increases in oviduct weight, plasma protein fraction 4 (the “beta-globulin”) and total plasma calcium. 3. 3. Ovulation was followed first by a decrease in calcium and later by a decrease in plasma fraction 4. 4. 4. Oviduct and adrenal weight decreased from peak summer levels by October. 5. 5. A single injection of estradiol 17β in post-reproductive females was followed by significant increases in plasma protein fraction 4 and calcium. 6. 6. This response did not occur in the absence of the pituitary gland.

Synthesis and degradation of glucose-6-phosphate dehydrogenase in the rat uterus.

Intravenous administration of 5 μg of estradiol or intrauterine application of 5 Mmoles of NADP+ in single or multiple doses increased the level of glucose-6-phosphate dehydrogenase activity (D-glucose-6-phosphate: NADP+ oxidoreductase, EC 1.1.1.49) in the uterus of the ovariectomized mature rat. Enzyme levels were increased 3.5-fold after 36 hr by a single injection of estradiol and 8-fold after 3 days by multiple doses of estradiol. Single or multiple applications of NADP+ resulted in a 2.4-fold increase. During the periods of decreasing enzyme activity following the above 4 treatments, the rate constants of enzyme synthesis (ks) and enzyme degradation (kd) were estimated as described by Segal and Kim (Proc Nat Acad Sci USA 50: 912, 1963). The basal rate of synthesis of glucose-6-phosphate dehydrogenase in the ovariectomized mature rat uterus was 0.0020 units/uterus X hr-1 and the rate of degradation was 0.014 hr-1 (t½ = 50 hr). These values were found to be independent of the treatment used to perturb the resting steady state and represent the average values obtained after all treatments. (Endocrinology89: 1131 1971)

The effect of neonatal administration of sex hormones on ribonucleic acid metabolism in the liver of male and female rats.

Fifteen minutes after the intraperitoneal injection of (32)P labelled phosphate, normal adult male rats show a higher incorporation of isotope into their liver nuclear RNA than do females. A single injection of testosterone into neonatal female rats causes a higher uptake of (32)P in adult life, while a single injection of oestradiol into male neonates lowers the incorporation in adult life. Gonadectomy at 4 weeks of age has only a small effect on the subsequent incorporation of (32)P into nuclear RNA either in control rats or in rats injected with sex hormones immediately after birth, showing that this effect of liver metabolism is mainly determined by the hormanal pattern at about the time of birth. The possible relevance of this sex difference in RNA metabolism to the different sex incidence of spontaneous or induced liver cancer is discussed.

THE EFFECTS OF OESTROGEN AND PROGESTERONE ON UTERINE CELL DIVISION AND EPITHELIAL MORPHOLOGY IN SPAYED, ADRENALECTOMIZED RATS

40 female spayed (20 of these adrenalectomized) rats were primed with 3 daily injections of 1 mcg estradiol-17beta in arachis oil. After 2 days without treatment 10 rats received oil only (5 spayed 5 spayed-adrenalectomized); 10 oil and .5 mcg estradiol; 10 4 mg progesterone and .5 mcg estradiol; and 10 4 mg progesterone. In spayed rats a single injection of estradiol stimulated mitosis in the luminal and glandular epithelia but not in the stroma. Pretreatment with progesterone suppressed epithelial mitosis and instead caused a mitotic response to estradiol in the stroma. Progesterone alone produced few or no mitoses in any of the tissues. Spayed rats that were also adrenalectomized gave similar results. In untreated rats the cytoplasm was pale and the nuclei and nucleoli small. Subnuclear and supranuclear lipid was present in distinct bands. Estrogen caused loss of the lipid and increased nuclear and nucleolar size and cytoplasmic basophilia. Changes after progesterone were the same whether estrogen was given or not. The cytoplasm was not basophilic. The nuclei were regularly aligned shrunken and elongated with small nucleoli. Both subnuclear and supranuclear lipids were increased. The lumen became sinuous in cross-section but there was no sign of corrugation of the epithelial surface. These results indicate that progesterone alters the mitotic responses to estrogen and the epithelial morphology of the rat uterus. The adrenal glands do not appear to mediate these actions.

Structural changes, related to reproduction, in the hypothalamus and in the pars tuberalis of the rhesus monkey: Part I. The hypothalamus. Part II. The pars tuberalis

Certain cells lining a circumscribed area of the III ventricle of the rhesus monkey differ from those cells which constitute the characteristic ependymal lining of the brain. The specialized cells studied comprise a number of types which differ in their structure, ultrastructure and staining affinities; all demonstrate features which are generally associated with active secretion and/or absorption. A group of such cells, which form a limited area of the latero-ventral walls of the anterior hypothalamus, have long processes which extend to the walls of the blood vessels in the median eminence. The evidence indicates that many of these cells, here described as Type B or tanycyte cells, secrete their products into the primary capillary network of the pituitary portal system. Another group of cells, here described as Type C and C' cells are found in a slightly more posterior position lining the floor of the ventricle; as yet there are no indications that these may secrete into blood vessels in the median eminence. Some of the specialized cells lining the III ventricle (Types B and C') showed changes in relation to reproductive activity: No such changes were observed in Type C cells nor in the characteristic ependymal cells (Type A) found elsewhere. Studies on normal and experimental male and female monkeys showed that Type B tanycyte cells differed in males and females and altered during the menstrual cycle in the female. Following ovariectomy these cells showed regressive changes but returned to a normal appearance after a single injection of oestradiol. In view of the close spatial relationship of the tanycyte ependyma to cells of the pars tuberalis it was interesting to note that pars tuberalis cells also altered in relation to the menstrual cycle. The evidence presented accords with the view that certain cells which line the III ventricle of the brain and have prolongations extending to pituitary blood vessels, thus linking the cerebrospinal fluid and the blood system in the region of the pituitary, may play a role in the regulation of pituitary function and thereby constitute an important neuro-endocrine system.

Sex difference in the release of luteinizing hormone evoked by progesterone.

SUMMARY Long-term gonadectomized female and male rats showed increased plasma luteinizing hormone (LH) activity (as measured by the ovarian ascorbic acid depletion method). A single injection of 20 μg. oestradiol benzoate or 2·5 mg. testosterone propionate after 3 days reduced the raised values significantly. Progesterone injected into gonadectomized rats primed with gonadal steroids exerts a positive feed-back action on the release of LH. In ovariectomized rats the injection of progesterone 3 days after a single injection of oestradiol or testosterone induced, a few hours later, a significant increase in plasma LH. In contrast, castrated male rats responded to progesterone with an increase in plasma LH only when they had been primed 3 days before with testosterone. This difference was not eliminated by gonadectomy on the first day of life. Androgen-sterilized ovariectomized rats failed to show an increase in plasma LH after progesterone when primed with testosterone but did so after priming with oestradiol. In male rats treated with testosterone in the early neonatal period, the normal LH release induced by progesterone in testosterone-primed animals was abolished. It is concluded that separate female and male patterns of LH release evoked by progesterone exist in the rat, and the difference between them is not determined by a postnatal differentiation in the neural mechanism which controls the secretion of LH.

A REFRACTORY PERIOD FOLLOWING OESTROGENIC STIMULATION OF CELL DIVISION IN THE MOUSE UTERUS

SUMMARY A single injection of oestradiol given to ovariectomized mice pretreated with progesterone for several days stimulates a large increase in cell division in the uterine stroma which reaches a maximum 24 hr. later. A second injection 48 hr. after the first, also stimulates stromal cell division, but a second injection 12–36 hr. after the first does not. This failure to respond is not due simply to depletion of the stock of cells ripe for division. Rather it appears that the uterus becomes insensitive to further stimulation for approximately 36 hr. Although a second injection 24 hr. after the first injection does not increase stromal cell division, it does lengthen the refractory period so that a third injection given at 48 hr. has no effect.

Effects of a Single Injection of Estrogen Early in the Estrous Cycle on Pituitary and Luteal Function in Ewes

Twenty-four mature ewes were studied to determine the effect of a single injection of estradiol−17β on pituitary and ovarian function. Twelve ewes received an intramuscular injection of 2 mg. of estradiol−17β the morning of day 5 and were killed the afternoon of day 7 (approximately 56 hr. later). Six untreated controls were killed on day 5 and six on day 7 of the estrous cycle. New ovulations were observed in eight of 12 treated ewes. Estrous behavior was induced in three of eight ewes which ovulated and one ewe that failed to ovulate. LH activity in pituitaries of estrogen treated ewes was significantly less than that observed for controls killed on the same day of the cycle, indicating an LH release which presumably led to the new ovulations. The total progesterone content of corpora lutea of estrogen treated ewes was significantly depressed by the treatment.

The induction of implantation in the mouse after ovariectomy

In the mouse ovariectomy before 81 hr. post coitum with daily progesterone treatment prevented blastocyst nidation. Implantation was induced by a single injection of oestradiol but there were no significant differences between the effects of doses of oestradiol in a range from 0.0025 to 2.5 n.g. Five hundred micro-grams of testosterone propionate induced implantation but 10.0 mg of progesterone was inactive. Oestriol was effective only at a dose of 2.5 or 12.5 μg, but 0.5 μg given as 2 injections before oestradiol completely inhibited oestradiol-induced implantation. This does not appear to be due to excessive oestrogenicity since 5.0 μg of oestradiol induced implantation in 3 of 16 mice. Implants resorbed in ov-ariectomised mice given progesterone only for 8 days, but developed normally if 0.008 μg of oestradiol, was given throughout embryogenesis.

The development of viable embryos after ovum transfers to long-term ovariectomised mice

Several weeks after ovariectomy, mice received daily progesterone injections 0.8 mg/day. On day 4 or 5 of progesterone treatment, blastocysts were transferred to one uterine horn, and implantation was induced by a single injection of oestradiol, 0.024 μg on day 5. Progesterone 1.6 mg/day and oestradiol 0.008 μg/day were essential to maintain the implants to day 19, when normal embryos were delivered by caesarean section. This seems to be the first recorded case of viable embryos developing from ova transferred to long-term ovariectomised animals.

Estrogen control of uterine carbohydrate metabolism: factors affecting glucose utilization.

The mechanisms by which estradiol- 17β controls uterine glucose metabolism have been further characterized by altering the rate of glucose uptake and the concentration of electron acceptors under in vitro incubation conditions. Results indicate that early estrogen effects on glucose metabolism are manifest via alterations in the rate of glucose transport into uterine tissue slices. Later estrogen effects on glucose metabolism are probably the result of increased availability of NADP+ and eventually elevated glucose-6-phosphate:NADP oxidoreductase activity. The rate of incorporation of l4C into total uterine lipids from glucose-l-14C, glucose- 6-14C and pyruvate-3-14C increases linearly as a function of time after estradiol injection. Dissimilar changes in the total activity of several dehydrogenases occur in the uterus of the ovariectomized rat 12 hr after a single injection of estradiol. (Endocrinology 79: 1069, 1966

INFLUENCE OF ESTRADIOL ON THYROID: SERUM RADIOIODIDE CONCENTRATION RATIOS OF GONADECTOMIZED AND HYPOPHYSECTOMIZED RATS.

The administration to ovariectomized female rats of estradiol benzoate for 3 consecutive days produces a significant elevation of thyroid:serum radioiodide concentration ratios (T:S) which is apparently not dependent upon the dosage employed in the range between 1 and 250 ng. Similar observations of enhanced thyroidal iodide concentrating activity in estrogen-treated hypophysectomized animals suggest that the stimulatory effect may be one which does not require mediation by pituitary thyrotrophin. The temporal response of the T:S ratios of ovariectomized female rats to a single injection of estradiol is characterized by an initial pituitary-dependent depression that is most marked 18 hr following injection. There is a subsequent elevation in concentrating activity that is maximal at 48–60 hr and that can also be observed in hypophysectomized-ovariectomized animals. The temporal response of T:S ratios of castrated male rats to a single injection of estradiol differs fundamentally from that of ovariectomize...

The effects of estradiol on acid mucopolysaccharide metabolism in oophorectomized rats

Fractions containing hyaluronic acid, chondroitin sulfate, heparin, and sulfatide were isolated from skin, intestine, and uterus of estradiol-treated and nontreated oophorectomized rats at various time intervals after the injection of glucose-U-C 14 and sulfate-S 35. A slight inhibition of sulfate uptake and stimulation of glucose uptake into the acid mucopolysaccharides of skin and intestine was observed; however, there were no apparent differences in the biological half-lives of acid mucopolysaccharides between the treated and nontreated animals. On the other hand, there was a marked stimulation of isotopic turnover in the uterine acid mucopolysaccharides of estradiol-treated oophorectomized rats. Surviving uterine segments, taken from rats killed at various time intervals after a single injection of estradiol, were incubated in vitro in the presence of glucose-U-C 14 and sulfate-S 35. After an initial lag period of approximately 6 hours the amounts and specific activities of hyaluronic acid and chondroitin sulfate were markedly stimulated by the estradiol injection. These observations suggest that there is a possible relationship between RNA and AMPS metabolism and that hyaluronic acid is not directly responsible for the estradiol-induced imbibition of water in the rat uterus.

STUDIES ON THE MECHANISM OF DECIDUALIZATION. I.

ABSTRACT The concept of an oestrogen surge as a prerequisite for successful decidualization of the progravid uterus and consequently nidation in the rat was tested. Experiments were designed to see whether administration of an oestrogen antagonist at specific times would block decidualization (and nidation); whether the ovary was the source of the oestrogen, and whether a single dose of oestrogen, in the absence of the ovary (if the ovary is the source) would allow the uterus to respond to a decidualizing stimulus. It was found that when given prior to the surge, the oestrogen antagonist prevented decidualization and interfered with nidation. The ovary is thus the source of the oestrogen; and a single injection of oestradiol can act as a substitute for the surge.

OVARIAN HORMONES AND UTERINE GROWTH: EFFECTS OF ESTRADIOL, PROGESTERONE AND RELAXIN ON CELL GROWTH AND CELL DIVISION IN THE RAT UTERUS1,2

The influence of ovarian hormones on the uterine growth of castrated rats was studied. The effects of estradiol-17β, alone or in various combinations with progesterone and relaxin, were investigated by measuring dry weight, total amounts of pentose and deoxypentose nucleic acids per uterus and dcoxyribonuclease activity. These analyses permit a distinction between hypertrophic (increase in cell mass) and hyperplastic (increase in cell number) growth. A time-study after a single injection of estradiol showed a rather fast response as regards increase in dry weight, nucleic acid net synthesis and increase in the cellular level of deoxyribonuclease activity. These effects, however, with the exception of deoxyribonuclease activity, were of very short duration. Estradiol under these conditions induced uterine growth both by hypertrophy and by hyperplasia. Simultaneous administration of progesterone had a restrictive effect on both types of growth. Progesterone given prior to estradiol had a pronounced stimulative effect on the hyperplastic activity. Progesterone injected after estradiol exercised uterotrophic effects in terms of both cellular growth and multiplication. Relaxin in a single dose together with estradiol augmented the hypertrophic capacity of estradiol. Repeated injections of this hormone in combination with estradiol and progesterone caused both hypertrophic and hyperplastic growth. Estradiol, alone or in combination with the other ovarian hormones, caused an invariable and sometimes considerable increase in the cellular level of deoxyribonuclease activity.

Influence of estradiol on nucleic acids, respiratory enzymes, and the distribution of nitrogen in the rat uterus

1. 1. The influence of single and repeated subcutaneous injections of 5 μg. estradiol on the uterus of the adult ovariectomized rat was studied. 2. 2. Estradiol was found to promote extensive synthesis of uterine ribonucleic acid (RNA) in contrast to little or no increase in desoxyribonucleic acid (DNA). As a result, the ratio of DNA: RNA changed from 3.4:1.0 in the castrate to 1.3:1.0 at 48 hr. after a single injection. At that time, both uterine weight and RNA content were maximal. 3. 3. Four daily injections of estradiol increased the succinate Q O 22 and the ascorbate Q O 2 to 400% of the castrate level. After a single injection of estradiol, activity reached a maximum at 48 hr. and then decreased. The activity of both enzymes was found to decline progressively for more than 1 month after castration. 4. 4. Determination of nitrogen in the water-extractable, alkali-soluble, and collagen fractions of uteri showed that although estradiol induced prompt increases in the absolute amount of nitrogen in each fraction, increments in the water-extractable moiety were particularly large. Thus, at 48 hr. after a single injection, when peak values were observed, the absolute amount of nitrogen in each of the three fractions amounted to 214, 167, and 144% of the control, respectively. 5. 5. The daily injection of 1 mg. progesterone for four consecutive days failed to alter the nucleic acids, respiratory enzymes, or the distribution of nitrogen from the castrate condition. 6. 6. The simultaneous occurrence of extensive synthesis of RNA, together with increased respiratory and synthetic functions in the absence of comparable increases in DNA, suggests that estrogen-induced uterine growth is based for the first 48 hr. on cytoplasmic growth as opposed to hyperplasia and may involve significant increases in mitochondrial mass.