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Biomedical subjects

E Weiner

Publications and source records attributed to E Weiner.

At least 91 records · Page 5Linked to original sources

Pituitary and ovarian function during contraception with one subcutaneous implant releasing a progestin, ST-1435.

Three women received one subcutaneous SilasticR capsule containing 40 mg of ST-1435 for contraception. Plasma levels of ST-1435, a 19-norprogesterone derivative, were measured during the treatment period of 13-15 months. The effects of treatment on pituitary and ovarian function were determined by assaying plasma concentrations of LH, FSH, estradiol and progesterone. The mean concentrations of ST-1435 during the treatment varied from 52 to 220 pg/ml in different subjects. These low concentrations of progestin were sufficient to suppress ovulation and make the implant effective for more than one year. No mid-cycle gonadotropin peaks were observed during the treatment. The subjects showed constantly low estradiol levels, thus also indicating a suppression of follicle development. Regular cyclic activity of the pituitary and ovaries, without the occurrence of ovulation, was observed in one subject. Increasing levels of estradiol parallelled a decrease of FSH and LH. It therefore seems that the negative feedback action of estradiol on gonadotropin release is unaffected but the positive feedback action of estradiol on LH appears to be blocked by the progestin ST-1435.

Contraceptive Agents, Female↗

Contraception with subcutaneous capsules containing ST-1435. Pituitary and ovarian function and plasma levels of ST-1435.

An RIA for a new progestin, ST-1435, was developed. Plasma concentrations of this steroid were measured in three women having three subcutaneous capsules, each containing 40 mg of ST-1435. Pituitary and ovarian functions were assessed by measuring plasma levels of LH, FSH, estradiol and progesterone. Plasma profiles of ST-1435 were characterized by high and irregular peaks all the way through the study period of 7-9 months. Concentrations below 100 pg/ml were not observed, whereas the highest peaks reached concentrations of 10.1 ng/ml. Plasma estradiol concentrations remained uniformly suppressed below 100 pg/ml, thus indicating a suppression in follicle development. As judged by constantly suppressed progesterone concentrations, no ovulations occurred during the treatment. Plasma FSH concentrations remained at the upper limit of the follicular phase, and those of LH at the lower limit of the luteal phase of the normal menstrual cycle. No midcycle gonadotropin peaks were observed.

Adult↗

Endometrial effects of levonorgestrel and estradiol: A Scanning electron microscopic study of the luminal epithelium.

Fertile women in the follicular phase possessed an uterine luminal surface with many ciliated cells and with non-ciliated cells, which carried numerous, fairly long microvilli. A moderate number of the non-ciliated cells had an irregular surface with small apical protrusions. Postmenopausal women had an endometrial surface containing rather flat cells. Ciliated cells were seldon encountered, and the non-ciliated cells possessed mostly only few short microvilli. When menopausal women had been wearing estradiol-containing intravaginal rings for three weeks, the uterine surface had developed many ciliated cells, and the non-ciliated cells now possessed many long microvilli. This appearance resembles that appearing during the follicular phase. Fertile women with levonorgestrel-containing subdermal implants or intravaginal rings showed a surface epithelium with few ciliated cells and with non-ciliated cells possessing short and irregular microvilli; that is, an epithelium less developed than that from a cyclic women. Adding estradiol to the levonorgestrel-containing intravaginal rings resulted in an estrogen response with an increase in number and length of the microvilli and an appearance of a few small apical protrusions.

Endometrium↗

Effects on sex hormone binding globulin of different oral contraceptives containing norethisterone and lynestrenol.

Six combined oral contraceptive drugs containing ethinyloestradiol or mestranol and norethisterone or lynestrenol were studied throughout six 21-day cycles in healthy female volunteers. There was always one menstrual cycle without treatment between every treatment cycle. Plasma levels of norethisterone were determined throughout treatment by use of a specific radioimmunoassay. Sex hormone binding globulin (SHBG) was measured by an ammonium sulphate precipitation method at the beginning and at the end of each treatment cycle. The results indicated an accumulation of norethisterone in plasma when 1 to 3 mg of norethisterone or lynestrenol was given. There was no obvious accumulation during treatment with 0.5 mg norethisterone. SHBG increased during treatment with all combinations studied. However, this increase was most pronounced with the 50 microgram ethinyloestradiol/l mg lynestrenol, 50 microgram mestranol/l mg norethisterone and 35 microgram ethinyloestradiol/0.5 mg norethisterone combinations. There was no statistically significant increase in SHBG with 50 microgram ethinyloestradiol/2.5 mg lynestrenol or 50 microgram ethinyloestradiol/3 mg norethisterone acetate combinations. The results indicated that the induction of SHBG by the synthetic oestrogens was antagonized by the progestogens in a dose-dependent manner. The effect on SHBG by a combind preparation could be one assessment of the oestrogenicity or androgenicity of the preparation.

Adult↗

Incorrect diagnosis of placental insufficiency in a patient with pre-eclampsia.

A case of pre-eclampsia is described where suspicion of placental insufficiency arose due to low estriol levels and a positive oxytocin challenge test (OCT). The cause, however, of these findings was later proven to be strictly fetal. It is concluded that low estriol levels and a positive OCT may be caused by a decreased placental capacity but specific tests of placental function, as for instance estimations of HPL in plasma and/or a DHAS-test, should be used to verify or rule out a suspicion of placental insufficiency.

Adult↗

Subdermal norethindrone pellets -- a method for contraception?

The mode of action of compressed pellets containing 85 per cent norethindrone (NET) and 15 per cent cholesterol was studied. Four pellets were inserted subcutaneously, in each of five healthy volunteers and left in place for 200--229 days. The NET content of the pellets varied between 23.9 mg and 25.6 mg; and the cholesterol content between 4.2 mg and 4.5 mg. Plasma levels of NET, estradiol and progesterone were determined by radioimmunoassays. Plasma levels of NET varied mostly between 1--2 ng/ml the first month after insertion. After two months plasma levels of NET ranged between 0.5 ng/ml and 1 ng/ml in all volunteers and there was a gradual decrease of the plasma NET levels throughout treatment. Pronounced day-to-day variations in plasma NET levels were recorded. The release rates of NET was calculated to be between 187 micrograms/day and 243 micrograms/day among the five volunteers. Ovulations occurred in four out of five subjects during treatment. This study indicates that the release of gestagen from four NET pellets was only initially high enough to completely inhibit ovulation and that to accomplish full contraceptive efficacy, a higher dose, i.e. more pellets, would have to be inserted.

Adult↗

Plasma levels of norethindrone and effect upon ovarian function during treatment with silastic implants containing norethindrone.

The study was made to evaluate the effect upon the ovarian steroid pattern during treatment with subcutaneously implanted silastic rods containing norethindrone. Four rods, each containing 37 mg norethindrone (NET), were implanted subcutaneously in five women and left in place for 135--200 days. Plasma levels of NET, estradiol and progesterone were determined by radioimmunoassays. After an initial peak found in all subjects, the plasma level of NET declined. Great day-to-day variations of NET were found. Ovulations were suppressed during treatment in three subjects. One subject had regular ovulations throughout treatment and in one subject a single ovulation was recorded. Peaks of estradiol without subsequent ovulation were found in two subjects. The bleeding pattern was irregular; three subjects had varying degrees of spotting and bleeding, two subjects were amenorrheic. The average daily release rate was 300/micrograms, calculated from the amount of steroids lost from the removed rods. This study indicates that the release of steroid from four NET rods is high enough only initially to completely inhibit ovulation.

Adult↗

Plasma levels of norethindrone after single oral dose administration of norethindrone and lynestrenol.

Single oral doses of 0.3 mg, 0.5 mg and 5 mg Norethindrone (NET) and 0.5 mg and 5 mg Lynestrenol (lyn) were given to five women. Lynestrenol is probably metabolized through NET and exerts its main biological activity as NET. Plasma concentrations of NET were determined by a radioimmunoassay at different intervals after administration of the tablets. Peak concentrations of NET were found within two hours after intake of each table. The plasma half life of Net after NET and lyn administration for the period 8-24 h was 8-11 h. No significant difference was found between the half life of NET and the NET tablets and after the lyn tablets. When 5 mg NET was given the plasma half life of NET for the period 24-72 h was around 10 h and this was significantly shorter than the half-life of NET after 5 mg lyn, which was 16 1/2 h. The systemic availability of the drugs was estimated by calculating and comparing the areas under the plasma concentration versus time curve (AUC). 0-24 H. The AUC 0.24 after 0.3 MG NET was almost identical to the AUC 0.24 after 0.5 mg lyn. The AUC 0-24 after 0.5 mg NET was significantly larger than after 0.5 lyn. No difference was found between the AUC 0-24 after 5 mg lyn and 5 mg NET. This study supports the concept of a conversion from lyn to NET. It also shows that there were only minor pharmacokinetic differences between the drugs when all samples were measured as NET.

Administration, Oral↗

Pituitary responsiveness to luteinizing hormone-releasing hormone during treatment with subdermal D-norgestrel implants in women.

It has previously been reported that subdermal implants containing d-norgestrel inhibit ovulation through blockage of the positive feedback action of estrogen on luteinizing hormone (LH) release. In this study 100 micrograms of LH-releasing hormone (LRH) were injected intravenously to test the pituitary reserve capacity for gonadotrophin secretion in three women with three 40 mg d-norgestrel rods implanted subdermally for more than one year. The gonadotrophin release to LRH varied and seemed related to the ovarian steroid concentrations at the time of the LRH infusion in a manner similar to that seen during the normal menstrual cycle. It is concluded that low plasma levels of d-norgestreol do not inhibit the pituitary responsiveness to LRH. The results indicate that the blocking action of the gestagen on the positive feedback of estradiol on LH release occurs at the hypothalamus or higher CNS centers.

Adult↗

Copper intrauterine contraceptive devices in adolescent nulliparae.

Copper intrauterine contraceptive devices (IUCDs) were used in 243 young nulligravidae attending a gynaecological clinic for schoolgirls in Uppsala between March 1973 and June 1975; 226 of these girls (93%) were seen again during December 1975 making a total of 3138 months of observation. At the time of follow up, 126 patients (55.8%) still had the IUCD in situ; 20% had expelled the IUCD and in another 24.2% the IUCD had been removed because of bleeding and/or pain or because of suspected pelvic inflammatory disease (7 patients). Twelve of the girls conceived during the period of observation making the Pearl index 4.6; nine of the conceptions occurred within nine months of the insertion of the IUCD. Unlike others we do not advocate the use of the IUCD for young nulligravidae.

Adolescent↗

Relation between sex hormone binding globulin and D-norgestrel levels in plasma.

In order to investigate the effect of changes in sex hormone binding globulin (SHBG) levels on d-norgestrel (d-Ng) levels in plasma, the plasma levels of SHBG and d-Ng were studied during one treatment cycle in 6 women on oral contraceptives containing d-Ng and ethinyloestradiol (EOE2) and in 3 women using subcutaneous silastic rods containing d-Ng concomitantly taking EOe2 for three weeks. A significant positive correlation between the SHBG and d-Ng levels was found in 7 of the 9 subjects studied. The results provide evidence for an in vivo binding of d-Ng to SHBG, a SHBG influence on the metabolic clearance rate of d-Ng and consequently a dependence of the plasma levels of d-Ng on the SHBG concentrations in the plasma. These findings support the concept that the clinically and biochemically observed anti-oestrogenic/androgenic effects observed in women on d-Ng containing medication are due to a displacement of testosterone from SHBG by d-Ng.

Contraceptives, Oral, Combined↗