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Biomedical subjects

P F Brenner

Publications and source records attributed to P F Brenner.

At least 19 recordsLinked to original sources
PubMed1979

Rate of metabolism of norethisterone in women from different populations.

The rate of metabolism of orally administered norethisterone was compared in fourteen centres by measuring plasma levels of the steroid by radioimmunoassay at varying times after oral administration of a 1 mg dose. The inter-centre differences were of the same order as the intra-centre differences. Variations in metabolism appeared not to be due to variations in body size.

Adult↗
PubMed1979

Origin of estrogen in normal men and in women with testicular feminization.

The purpose of this study was to quantify the various sources of estrone (E1) and 17 beta-estradiol (E2) production in normal men and in women with testicular feminization. The mean production rate of E1 in four young adult men was 58 micrograms/24 h, while that of E2 was 44 micrograms/24 h. In these men, E1 production could be accounted for totally by extraglandular formation through 1) aromatization of plasma androstenedione, 2) conversion of E2 which was formed from the aromatization of plasma testosterone, and 3) conversion of secreted E2. In these men, only 12 micrograms or less of E2 production could not be accounted for by extraglandular formation from plasma C19 precursors, and is presumed to have arisen by testicular secretion. In six women with testicular feminization, the mean production rate of E1 was 99 micrograms/24 h, while that of E2 was 77 micrograms/24 h. THe amount of E2 production that arose by glandular secretion could be computed in four of these women and was considerably greater than that found in the young adult men. In these women with testicular feminization, an average of 44 micrograms/24 h E2 could not be accounted for by extraglandular formation and is presumed to have arisen by testicular secretion. The mean plasma production rate of testosterone in the normal men was 5.7 mg/24 h, while that in the women with testicular feminization was 8.3 mg/24 h. However, the range of plasma production rates of testosterone in the women with testicular feminization was large (1.3--17.0 mg/24 h).

Adolescent↗
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

A radioimmunoassay for norethindrone (NET): measurement of serum NET concentrations following ingestion of NET-containing oral contraceptive steroids.

A sensitive and reliable radioimmunoassay (RIA) for the measurement of norethindrone (NET) in serum has been established employing anti-11 alpha-hydroxynorethindrone 11-hemisuccinyl-bovine serum albumin serum in conjunction with norethindrone-3-(0-carboxymethyl) oximino-[125I]-iodohistamine. Of a number of ring A reduced NET metabolites, only 17 beta-hydroxy-17 alpha-ethinyl-5 beta-estran-3-one (43%) and 17 alpha-ethinyl-5 alpha-estrane-3 beta, 17 beta-diol (15.7%) cross-reacted appreciably in this RIA. Ethinyl estradiol (EE2) and mestranol (MEE2) exhibited cross-reactions of only 1.1 and 0.4%, respectively. Serum NET levels were measured in four groups of 3 women, each ingesting either 1 mg NET plus 0.05 mg MEE2 (Norinyl 1 + 50 or Ortho Novum 1/50), 0.5 mg NET plus 0.035 mg EE2 (Brevicon) or only 0.35 mg NET (Micronor) daily for 5 consecutive days. Peak serum NET levels were observed within 1/2 to 4 hours after oral intake and fell precipitously thereafter. After reaching a maximum, serum NET concentrations declined in a manner consistent with at least two disposition phases. The average half-life for the first disposition phase was 2.3, 3.4, 3.9 and 4.4 hours in subjects ingesting Norinyl 1 + 50, Ortho Novum 1/50, Brevicon and Micronor, respectively. Peak and 3-hour post-ingestion serum NET concentrations were dose-related but showed considerable subject-to-subject variations. Following discontinuation of tablet intake, serum NET levels remained detectable (greater than 0.05 ng/ml) for at least 5 days in all 3 women who had taken Ortho Novum 1/50, but in none of the other 9 volunteers. These results suggest that different preparations of identical doses and combinations of oral contraceptive steroids may yield different serum NET profiles. However, due to considerable subject-to-subject variations, larger numbers of subjects are required for a conclusive investigation.

Adult↗
PubMed1978

Comparison of the effects of contraceptive steroid formulations containing two doses of estrogen on pituitary function.

A pituitary stimulation test with gonadotropin-releasing hormone (GnRH) and thyrotropin-releasing hormone (TRH) was undertaken to determine (1) whether pituitary responses to GnRH vary in individual women taking oral contraceptive steroids over time, (2) whether a less suppressive pituitary gonadotropin effect is produced by formulations containing less than 50 microgram of estrogen, and (3) to obtain more information concerning prolactin secretion in users of oral contraceptive steroids. The same subjects who had had a suppressed luteinizing hormone (LH) and follicle-stimulating hormone (FSH) response 6 to 9 months previously also had a suppressed response, indicating that this effect persists over time. Contraceptive formulations containing less than 50 microgram of estrogen have a lesser suppressive effect on LH release than do formulations containing 50 microgram of estrogen or more. The basal prolactin (PRL) response as well as the maximal PRL response to TRH were found to be significantly greater in subjects using oral contraceptives than in the control subjects. However, no difference in PRL response was found between the subjects using low or high doses of estrogen fomulations.

Adult↗
PubMed1978

A randomized comparison of the Ypsilon-Y and Lippes loop D intrauterine devices in parous women.

A randomized single-blind clinical study was performed to determine whether there was any difference in the termination event rates between parous women using the Ypsilon-Y intrauterine device (IUD) and those using the Lippes loop D. A total of 174 women received the Ypsilon-Y IUD and 173 women received the loop D. A significant higher incidence of expulsion occurred with use of the Ypsilon-Y IUD.

Adolescent↗
PubMed1977

Serum levels of d-norgestrel, luteinizing hormone, follicle-stimulating hormone, estradiol, and progesterone in women during and following ingestion of combination oral contraceptives containing dl-norgestrel.

Three formulations of dl-norgestrel were administered daily to groups of three women for five consecutive days. The serum levels of d-norgestrel were related to the dosage of dl-norgestrel ingested. Peak concentrations in the circulation of synthetic gestagen were attained a half hour to three hours after oral administration, followed by a rapid and sharp decline in levels until the next dose. Three women received 500 micrograms of dl-norgestrel and 50 micrograms of ethinyl estradiol for 21 days followed by six to seven days of no medication for two consecutive cycles. The gonadotropins remained suppressed for four to six days when therapy was discontinued. The daily concentrations of estradiol varied from less than 5 to 81 pg. per milliliter, and there was no difference in estrogen values during the nontreatment and treatment days. Due to the long half life of norgestrel, the one-week pill-free interval is not long enough for the complete recovery of the reproductive axis from the inhibition of oral contraceptives.

Adult↗
PubMed1977

The effect of contraceptive steroids on hypothalamic-pituitary function.

A study was performed to obtain additional information about the effects of oral contraceptives on pituitary function. A sequential pituitary stimulation test (SST) was used to study normal control women who then received either a combination pill with 50 mug of ethinyl estradiol or an injectable or oral progestin for three weeks, after which the test was repeated. The same test was also performed on five long-term oral contraceptive users. The SST consists of measurement of growth hormone (GH), thyroid-stimulating hormone (TSH), prolactin (PRL), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) at frequent intervals after stimulation by hypoglycemia, thyrotropin-releasing hormone, and gonadotropin-releasing hormone. GH and TSH release following stimulation were unaffected by the use of contraceptive steroids, while PRL release was increased by both the combination pill and the progestin alone. LH and FSH release was decreased in the three short-term and most of the long-term users of the combination pills but was not decreased in two of the long-term users as well as in those receiving the progestin alone. These results indicate that the combination oral contraceptives have a direct effect upon the pituitary gland, causing an increase in prolactin release and a decrease in gonadotropin release. This effect varies among individuals receiving the same formulation and may be related to the development of syndrome of postpill amenorrhea-galactorrhea.

Contraceptives, Oral↗
PubMed1977

Termination of early gestation with a vaginal polysiloxane device impregnated with (15S)-15 methyl prostaglandin F2alpha methylester.

An investigation of the abortifacient activity of (15S)-15 methyl prostaglandin F2alpha methyl ester released from a vaginal polysiloxane device was performed in eleven pregnant women of 49 days gestation or less. Bleeding and contractions were induced in all women, but only seven aborted their pregnancies. Five subjects received a vaginal device impregnated with 3 mg of drug and two aborted fetal tissue. Six women were given a vaginal device containing 5 mg of drug and five aborted fetal tissue. Ten of the patients had significant side effects, nausea, emesis, diarrhea and chills. Six women expelled the device prior to the termination of therapy. This prostaglandin analogue, when administered from a vaginal polysiloxane device in early gestation was an effective abortifacient but was accompanied by systemic side effects and a high incidence of expulsion of the device prior to its scheduled removal.

Abortion, Induced↗
PubMed1977

Ectopic pregnancy following tubal sterilization surgery.

In a consecutive study of 100 women with the surgical diagnosis of ectopic pregnancy confirmed by histologic examination, 7 women were found to have had prior tubal sterilization surgery. In 3 of these cases the sterilization procedure was bilateral tubal fulguration. The diagnosis of ectopic pregnancy must be given careful consideration if patients conceive after a tubal sterilization procedure of any type.

Adult↗
PubMed1976

Studies on the pattern of circulating steroids in the normal menstrual cycle. I. Simultaneous assays of progesterone, pregnenolone, dehydroepiandrosterone, testosterone, dihydrotestosterone, androstenedione, oestradiol and oestrone.

In an attempt to analyze the multiple changes and interactions in circulating steroid levels in the peri-ovulatory and peri-menstrual periods, the plasma levels of immunoreactive luteinizing hormone (LH), progesterone and unconjugated pregnenolone, dehydroepiandrosterone, testosterone, oestradiol and oestrone were assayed daily during a complete cycle in 17 normally menstruating women. In 14 of the 17 subjects studied androstenedione and unconjugated dihydrotestosterone were also estimated. The day of the LH-peak and the first day of menstruation, respectively, were used to synchronize the peri-ovulatory and peri-menstrual plasma levels of the various steroids. With the exception of dehydroepiandrosterone and dihydrotestosterone, the plasma levels of all steroids exhibited significant, but different changes during the cycle. Testosterone levels showed a slight but significant increase around the LH-peak, whereas the levels of pregnenolone and androstenedione were higher in the post-ovulatory than in the pre-ovulation periods. The levels of oestradiol and oestrone, as well as the ratios of oestradiol to oestrone gradually increased from the low values observed in the early proliferative phase to pre-ovulatory peak values. The relationship between peaks of oestradiol and oestrone and that of LH exhibited great individual variation. The same was true for the individual oestradiol to oestrone ratios. The combination of several steroidal signals did not improve the predictive value of the analyses. However, an increase of individual progesterone values by at least 0.35 ng/ml from the day preceding the LH-peak to the day of the LH-peak was observed in 13 of the 17 subjects. It is suggested that for the early detection of the LH surge and prediction of the subsequent ovulation daily assays of plasma progesterone are of more value than the assay of the other steroids investigated.

Adult↗
PubMed1975

Clinical study of a progesterone-releasing intrauterine contraceptive device.

A double-blind clinical study was performed to determine whether the release of progesterone from an intrauterine contraceptive device (IUD) had any effect on IUD event rates. A total of 101 women received intrauterine contraceptive devices containing progesterone, resulting in the accumulation of 877 women-months experience; 100 women received IUD's without steroid, resulting in the accumulation of 780 women-months. The only significant difference was a higher incidence of pregnancy in those patients using devices which did not contain progesterone.

Adult↗