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At least 19 recordsLinked to original sources
PubMed1979

Some estrogenic effects of two oral contraceptives consisting of norgestrel and two different doses of ethynylestradiol.

Some biological and biochemical effects (i.e. KPI, cervical mucus, SHBG and ceruloplasmin) as well as serum ethynylestradiol and serum norgestrel, following the use of two oral contraceptives containing the same amount of norgestrel (dl-norgestrel 0.5 mg) and either 30 microgram or 50 microgram of ethynylestradiol were compared. There was no difference in the clinical features in either group of patients. There was a statistically significant difference in the levels of unconjugated ethynylestradiol but not in the other biochemical parameters studied. It is concluded that the absence of any such difference might be attributable to the strong antiestrogenic effects of dl-norgestrel.

Adolescent↗
PubMed1975

The urinary metabolites of 17alpha-ethynylestradiol-9alpha,11xi-3H in women. Chromatographic profiling and indentification of ethynyl and non-ethynyl compounds.

Metabolites of 17alpha-ethynylestradiol (EE2) were obtained from human urine following ingestion of tritium-labeled EE2. Over 95% of the recovered activity was found as conjugated steroids and these were separated into four groups by chromatography of the urine extract on Sephadex LH-20 with chloroform-methanol (1/1) + 0.01M NaCl. The two major conjugate fractions appeared to be almost exclusively glucosiduronates. Enzymatic hydrolysis liberated at least ten different EE2 metabolites as shown by chromatography on Sephadex LH-20 with benzene-methanol (85/15). After additional separation and purification of these metabolites, positive identification was obtained for nine radioactive compounds by either gas liquid chromatography-mass spectrometry or reverse-isotope recrystallization. Five were ethynyl compounds: EE2, 2-MeO EE2, 16beta-OH EE2, 2-OH EE2 and 6alpha-OH EE2. The other four were de-ethynylated estrogens: estrone, estradiol-17beta, estriol, and 2-Me-O-estradiol-17beta.

Chromatography, Gas↗
PubMed1977

Interaction of rifampicin treatment with pharmacokinetics and metabolism of ethinyloestradiol in man.

[6,7-3H]Ethinyloestradiol (50 microng) was administered intravenously to volunteers and the free extractable ethinyloestradiol in the plasma was measured. The compound showed a biphasic plasma decline. The half-life of the second phase was 7.5+/-1.7 (SD) hours. Administration of rifampicin (600 mg for 6 days) shifted the half-life of ethinyloestradiol to 3.3+/-0.9 h while the apparent volume of distribution for the second phase of elimination was not changed. When [2,4,6,7-3H]ethinyloestradiol (100 microng) was administered orally, some of the tritium was released by oxidative metabolism from the steroid and transformed to tritiated water (HTO) which equilibrated with whole body water. This portion, normally 7.17+/-1.66% of the tritium dose, was increased by previous administration of rifampicin to 10.62+/-2.27%. The initial rate of oxication of [2,4,6,7-3H]ethinyloestradiol was increased more than twofold by rifampicin treatment. The results are consistent with previous findings that rifampicin induces the oestrogen-2-hydroxylase in the endoplasmic reticulum of human liver, and explain the reduced effectiveness of ethinyloestradiol in oral contraceptives, if the patients are treated with rifampicin.

Administration, Oral↗
PubMed1978

Ethinyl estradiol in peripheral plasma after oral administration of 30 microgram and 50 microgram to women.

Plasma levels of ethinyl estradiol were measured by radioimmunoassay in five women after oral administration of 30 microgram and of 50 microgram of ethinyl estradiol. Peak levels of ethinyl estradiol were mostly observed within two hours after the tablet intake. The peak concentrations found were 50--90 pg and 95--135 pg for the two doses administered. Twenty-four hours after the administration of the tablets, the plasma concentration of ethinyl estradiol did not exceed the plasma blank values (25 pg/ml) in most women.

Administration, Oral↗
PubMed1979

An investigation of the pharmacokinetics of ethynylestradiol in women using radioimmunoassay.

A radioimmunoassay for ethynylestradiol (EE) which is applicable to plasma samples obtained from women, who have taken a combination type oral contraceptive, has been developed and fully validated. Plasma concentration of EE rise to a peak of 128 pg/ml following the oral administration of 50 microgram EE. Following the intravenous administration of the same dose of EE, plasma concentrations of the steroid declined biexponentially, the two half-lives being 0.83 and 6.75 hours. Comparison of the results of the intravenous and oral administration of the steroid suggested that its oral bioavailability is 42%. Although EE thus has a lower bioavailability than norethindrone, the pharmacokinetics of the two steroids, as reflected by half-lives, plasma clearance and volume of distribution, are very similar. The occurrence of a secondary peak in plasma at around 12 hours after dosing gave strong evidence that EE undergoes enterohepatic circulation in women; an event that may have considerable clinical significance.

Administration, Oral↗
PubMed1979

Accumulation of ethinylestradiol in blood and endometrium of women taking oral contraceptives: the sequential therapy.

A radioimmunoassay to quantitate ethinylestradiol (EE-2) in both plasma and endometrium is described. In 29 women under sequential oral contraceptive therapy (chlormadinone acetate, 2 mg, plus mestranol, 80 microgram) for 6 to 84 months, a single blood sample and a single endometrial sample were simultaneously obtained on different days of the pseudomenstrual cycle. In 24 women under 40 years of age the mean plasma EE-2 concentrations were similar during the first (989 +/- 94 pg/ml) and the second half of the cycle (1053 +/- 186 pg/ml) (P greater than 0.05). A similar finding was observed with regard to mean endometrial EE-2 concentrations (3.55 +/- 2.1 and 5.89 +/- 1.7 microgram/gm of wet tissue, respectively). On the other hand, five women over 40 years of age had plasma EE-2 concentrations similar to those of the previous group, but the mean endometrial EE-2 concentrations was 0.9 +/- 0.6 microgram/gm of wet tissue (P less than 0.05). Although plasma follicle-stimulating hormone and luteinizing hormone did not show midcycle peak values, complete suppression of both gonadotropins was not observed. These results show that endometrium has a great ability to concentrate EE-2, and this ability seems to be greater in women below age 40 than above. Whether or not this observation might be related to the known higher incidence of endometrial cancer in women less than 40 years old who have been under chronic sequential oral contraceptive therapy cannot be disclosed from this limited number of determinations.

Adolescent↗
PubMed1977

Oestrogenic activity of oestradiol-decanoate after oral administration to rodents.

Oestradiol-decanoate, dissolved in arachis oil and orally administered to rodents, produces oestrogenic effects. Compared on a molecular basis the ester has 0.1-1.0 times the activity of ethinyl oestradiol, dependent on the species and the parameter studied. The effects of oestradiol-decanoate are less or absent when the oil is omitted. It is likely that absorption of the steroid ester takes place via the intestinal lymphatics in conjunction with the oil.

Administration, Oral↗
PubMed1975

[Plasma concentrations of LH and of sex steroids during the normal menstrual cycle and during contraceptive treatment].

The authors have studied the long-term effects of combined oestrogen-progestogen on the secretion of gonadotrophins and on ovarian function. Estimation of the radio-immune levels of the plasma concentrations of the pituitary luteinizing hormone (LH), of oestradiol (E2), of progesterone (P) and of 20 alpha hydroxyprogesterone (20 alpha OHP) and of testosterone (T) served as a base for this study. A test cycle and 8 cycles in which a combination of 50 micrograms of ethinyl-oestradiol and 0.5 mg of norgestrel were administered were studied in 4 normal volunteer women. A pituitary stimulation test using 50 micrograms of gonadotrophin "releasing factor" (LH-RH) was given during the 7th cycle. Ovarian stimulation using human menopausal gonadotrophins (HMG) was given during the 8th cycle of treatment in 3 of the women and in 3 other subjects. Pituitary secretion of LH and ovarian secretion of E2 and P are partially inhibited. Pituitary response to the injection of LH-RH stays normal but 5 out 6 patients had no response to stimulation by gonadotrophins. These results allow us to conclude that the lowering of production of gonadotrophins during treatment with combination oestrogen and progestagens is responsible for inhibition of ovarian activity, and that there is a delay before the latter respond to stimulation by either endogenous or exogenous gonadotrophins.

Adult↗
PubMed1978

Factors affecting pituitary gonadotropin function in users of oral contraceptive steroids.

In order to determine whether certain factors influence the direct pituitary suppressive effect of contraceptive steroid, 50 subjects who had used various formulations of oral contraceptive steroids for periods of time ranging from one to nine years were stimulated with 50 microgram of gonadotropin-releasing hormone (GnRH) during the last week of oral contraceptive ingestion. The response of lutinizing hormone (LH) and follicle-stimulating hormone (FSH) was compared to the results obtained in nine control subjects with regard to: (1) age of subject. (2) type of contraceptive formulation used, and (3) length of use. Prestimulation levels of LH and FSH, respectively, were significantly decreased in 37 (74 per cent) and 42 (84 per cent) of the subjects. Following GnRH stimulation, peak responses of serum LH and FSH, respectively, were also significantly lower than those in the control subjects in 40 (80 per cent) and 45 (90 per cent of the subjects. The degree of suppression of pituitary gonadotropins, both before and after GnRH administration was significantly correlated with the type of steroid formulation used, being greatest with a combination of d-norgestrel and ethinyl estradiol. No correlation was found with length of use of oral contraceptives or age of the subjects.

Adult↗
PubMed1978

Serum levels of FSH, LH, estradiol-17 beta and progesterone following the administration of a combined oral contraceptive containing 20 micrograms ethinylestradiol.

An oral contraceptive containing 20 micrograms of ethinylestradiol and 250 micrograms of levonorgestrel was given to 5 normally menstruating women for two consecutive cycles. Peripheral serum levels of FSH, LH, estradiol-17 beta and progesterone were determined during the treatment period and during two control cycles, one immediately before, and one immediately after treatment. In all 5 women studied there were no LH peaks and no luteal phase levels of progesterone during the treatment cycles indicating complete inhibition of ovulation. 4 of the 5 women showed no biphasic estradiol pattern. Posttreatment control cycles showed reestablished ovulatory pattern in 4 of the 5 subjects.

Adolescent↗