Increased cardiovascular reactivity to agiotensin caused by renin.

After a short period of tachyphylaxis, there is a marked and sustained enhancement of pressor re sponses to renin and angiotensin during chronic administration of renin.

Progesterone production by dispersed cells from human corpus luteum: stimulation by gonadotrophins and prostaglandin F 2 alpha; lack of response to adrenaline and isoprenaline.

Progesterone production was assessed following short-term incubations of luteal cell suspensions prepared from tissue samples of human corpora lutea obtained at specific times throughout the luteal phase of the menstrual cycle. Luteal cells responded rapidly and sensitively to human chorionic gonadotrophin (HCG: concentration required for 50% maximum response, 0.1--1.0 i.u./ml) with a maximum level of response (five- to tenfold higher than basal production) similar to that elicited by human LH or N6,O2'-dibutyryl cyclic AMP. In the absence of gonadotrophin or in the presence of sub-maximal (but not maximal) concentrations of HCG, progesterone production by mid-luteal phase cells was stimulated by prostaglandin F 2 alpha (1 mumol/l, an effect not observed during the late-luteal phase. L-Adrenaline and L-isoprenaline failed to elicit significant increases in the level of progesterone production.

Stimulation by human chorionic gonadotrophin of oestradiol production by dispersed cells from human corpus luteum: comparison with progesterone production; utilization of exogenous testosterone.

Cell suspensions were prepared from tissue samples of human corpora lutea obtained during the mid- and late-luteal phase of the menstrual cycle. Both oestradiol and progesterone production by dispersed cells were stimulated by similar concentrations of human chorionic gonadotrophin (hCG). As the degree of stimulation of production by hCG was greater for progesterone than for oestradiol (five- to tenfold compared two- to threefold higher than basal production), the ratio of progesterone to oestradiol produced varied according to the level of trophic stimulation. A comparison of cell suspensions prepared form mid- to late-luteal phase corpora lutea, exposed to the same concentration of hCG (10 i.u./ml) in vitro, did not reveal a shift to oestradiol production in the late-luteal phase. Provision of additional testosterone during incubation raised the level of oestradiol production by dispersed luteal cells. At an optimum concentration of testosterone (l mumol/l), oestradiol synthesis was not raised further in the presence of hCG or N6, O2'-dibutyryl cyclic AMP, suggesting a lack of induction or activation of the aromatase system by gonadotrophin in short-term cultures. Basal and stimulated levels of progesterone production were not significantly impaired in the presence of testosterone.

Lack of direct inhibitory action of oxytocin on progesterone production by dispersed cells from human corpus luteum.

Suspensions of luteal cells were prepared from samples of human corpora lutea obtained during the luteal phase of menstrual cycles. Addition of oxytocin (1 mumol/l) to the various cell preparations had no effect on either basal production of progesterone or on steroidogenic responses to a range of concentrations of gonadotrophin.

Augmentation by epidermal growth factor of basal and stimulated progesterone production by human luteinized granulosa cells.

Human granulosa cells were prepared from follicular aspirates obtained during oocyte collection for in vitro fertilization. Following several days in culture, cells were washed and then progesterone output was measured in 2-h incubations. After culture for 3 days, incubated cells responded well to human chorionic gonadotrophin (hCG) and prostaglandin (PG) E2 with similar levels of maximum response. Exposure of cultured cells to epidermal growth factor (EGF) for 2 days (days 3-5) led to substantial increases both in basal production and in responses to hCG and PGE2 during subsequent incubations. These effects of EGF were not accompanied by measurable increases in DNA levels in cultures over this time. Results may point to a possible paracrine role for EGF-like factors modulating the activity of cells forming the early corpus luteum.

Inhibitory action of chemically deglycosylated human chorionic gonadotrophin on hormone-induced steroid production by dispersed cells from human corpus luteum.

The biological activity of deglycosylated human chorionic gonadotrophin (hCG) prepared by treatment of the native hormone with anhydrous hydrogen fluoride was evaluated using suspensions of dispersed cells from biopsies of human corpus luteum obtained during the luteal phase of normal menstrual cycles. A reproducible pattern of response to hCG in terms of progesterone production by luteal cells was established for a range of luteal ages. Deglycosylation of hCG led to a diminished level of maximum response to the hormone. Co-incubation of luteal cells with a level of hCG just sufficient to elicit a maximum response and increasing concentrations of deglycosylated hCG led to a progressive inhibition of the hormonal response; at a concentration of 10(3) ng deglycosylated hCG/ml (a tenfold excess of deglycosylated hCG over the native hormone), hCG-induced progesterone production was reduced by about 50%. Deglycosylated hCG therefore acts as a partial antagonist for the action of hCG on human luteal cells.

Effects of a long-acting analogue of LH releasing hormone on human and rat corpora lutea.

Dispersed luteal cells were prepared both from samples of human corpora lutea obtained during normal menstrual cycles and from luteinized rat ovaries of animals pretreated with pregnant mare's serum gonadotrophin and human chorionic gonadotrophin (hCG). Addition of the long-acting analogue, D-Ala6-des-Gly10-LH releasing hormone ethylamide (D-Ala6-LHRH), to rat luteal cells caused a small but significant increase in progesterone production. An inhibitory action of the analogue on hCG-stimulated steroidogenesis by rat luteal cells was confirmed. Addition of D-Ala6-LHRH to suspensions of human luteal cells had no effect on either basal or hCG-stimulated progesterone production. Studies on the interaction of 125I-labelled D-Ala6-LHRH with the dispersed cell preparations, while confirming the presence of displaceable binding to rat luteal cells, failed to detect any equivalent binding to human luteal cells. Low levels of displaceable binding observed using homogenates of human corpora lutea are interpreted as being of doubtful physiological significance in view of the negative findings obtained with the intact cell system.

Pregnancy-specific-beta 1-glycoprotein: effect on lymphocyte proliferation in vitro.

The effects of three different preparations of pregnancy-specific-beta 1-glycoprotein (SP1) were investigated in parallel with progesterone, oestradiol and human chorionic gonadotrophin (hCG) on the proliferative response of lymphocytes in the mixed lymphocyte reaction (MLR), and to the mitogens phytohaemagglutinin (PHA) and pokeweed mitogen (PWM). A dose-related inhibition of the MLR was obtained with SP1 at 2.5-10 mg/l. SP1 also inhibited the PHA response at 10 mg/l, but had no effect on the PWM response at these concentrations. Progesterone and oestradiol inhibited all systems at 10-20 mg/l while hCG inhibited all systems at 1500-3000 IU/ml. The observations suggest that SP1 selectively inhibits the proliferative responses of T lymphocytes at the concentrations studied.

Comparison of serum and urine hCG levels with SP1 and PAPP-A levels in patients with first-trimester vaginal bleeding.

Serum levels of human chorionic gonadotropin (hCG) in patients with threatened abortion are compared to the values in normal pregnancy. The predictive value was 93%, the sensitivity was 84%, and the prediction of gestational viability was 81% for the threatened group. These results compare favorably with urinary pregnancy testing and are similar to those obtained with the assay of Schwangerschaftsprotein I. Human chorionic gonadotropin was, however, a much better predictor of pregnancy outcome than pregnancy-associated plasma protein-A.

Observations on the variability of plasma estriol.

Total plasma estriol and unconjugated plasma estriol were measured daily for 8 days in 9 women during the 38th week of pregnancy. The average coefficient of variation of total estriol concentration was 15.0%; that of unconjugated estriol was 16.5 per cent.

Plasma estrogens and pregnancy-associated plasma proteins: a study of their variability in late pregnancy.

The plasma concentration of several estrogens (unconjugated estradiol and estriol, total estriol, and estriol sulfate) and of the placental proteins hPL and PAPP-C were measured daily for 8 days in 9 subjects. The steroids showed coefficients of variation ranging from 14 to 21%. The proteins were much less variable (PAPP-C 5% and hPL 6%).

Placental protein 14 secretion during in vitro fertilization cycles with and without human chorionic gonadotropin for luteal support.

OBJECTIVE: To investigate levels of placental protein 14 (PP14) in in vitro fertilization (IVF) patients with and without exogenous human chorionic gonadotropin (hCG) for luteal support. DESIGN, PATIENTS: Thirty-one women undergoing IVF were studied. For 18 women, hCG was administered in the luteal phase, and 12 became pregnant. Five pregnancies occurred in 13 women not receiving exogenous hCG. SETTING: All the patients attended the University of Southampton/Chalybeate Hospital IVF program. RESULTS: There was no change in PP14 levels 2 days after embryo transfer (ET), but small significant rises were noted by day 8 in all patients. Thereafter, levels rose further in pregnant subjects but showed no change in nonpregnant patients. The highest level of PP14 was seen in the group of women on hCG support, but there was no overall statistical difference between those on support and those not. In the nonpregnant group, there was no significant correlation between progesterone (P) and PP14 8 days from ET, whereas a highly significant correlation was noted in the pregnant group. CONCLUSIONS: Neither hCG nor P are primary factors in the control of endometrial PP14 secretion, but PP14 and P may have common underlying control mechanisms.

Improved separation of motile sperm in asthenospermia and its application to artificial insemination homologous (AIH).

A method is described for the separation of motile sperm from semen by "migration' into a diluent, providing a large area of interface between the semen and the diluent and resulting in a good yield of motile sperm (58%), with a mean percentage of motility of 95%. The method provides a specimen free of seminal plasma and debris and suitable for intrauterine insemination in less than two hours. The motile fraction was used for AIH treatment of 20 couples with a mean of 4 years' infertility, where the female factor had been excluded and the male was asthenospermic. After a mean of six cycles, three pregnancies were achieved. Improvement of the percentage of motility alone did not, in this study, give a significant improvement in conception rates when compared with accepted cycles with the placebo.

The relation between immunoglobulin G antibodies to Chlamydia trachomatis and poor ovarian response to gonadotropin stimulation before in vitro fertilization.

OBJECTIVE: To determine whether a relation exists between previous exposure to Chlamydia trachomatis and impaired ovarian response to gonadotropin stimulation. DESIGN: Controlled clinical study. SETTING: Two university IVF centers. PATIENT(S): Two hundred forty-two patients receiving IVF treatment and 81 control patients. Ninety-four patients with a poor response to IVF, defined by cycle cancellation in response to a daily stimulation dose of 300 IU of FSH, and 148 patients with a good response were matched for age. Twenty-eight pregnant controls and 53 controls of proven fertility also were included. INTERVENTION(S): Serum samples were obtained from patients and controls. Serum levels of immunoglobulin (Ig) G antibodies to C. trachomatis were determined by ELISA. MAIN OUTCOME MEASURE(S): The prevalence of serum IgG antibodies to C. trachomatis in critically defined poor responders was compared with that of age-matched good responders. RESULT(S): A significantly higher proportion of poor responders had serum IgG antibodies to C. trachomatis compared with good responders (44.7% and 30.4%, respectively). Patients undergoing IVF had a significantly higher prevalence of IgG antibodies to C. trachomatis (36%) than did either pregnant or nonpregnant controls (12%). CONCLUSION(S): A significantly higher prevalence of serum IgG antibodies to C. trachomatis was observed in critically defined poor responders, suggesting a possible detrimental effect of C. trachomatis on subsequent ovarian function.

The variable influence of an alpha component in pregnancy plasma on four different assay systems for the measurement of pregnancy-specific beta1 glycoprotein.

Four methods (radioimmunoassay, electroimmunoassay, laser nephelometry and kinetic immunoturbidimetry) have been evaluated for the measurement of proteins with pregnancy-specific beta1 glycoprotein immunoreactivity. The influence of two maternal plasma proteins with different electrophoretic mobilities (alpha2 and beta1) but with similar antigenic determinants has been assessed in each assay system. The radioimmunoassay method, which utilises a homogeneous preparation of pregnancy-specific beta1 glycoprotein for the preparation of iodinated tracer, and the kinetic immunoturbidimetric assay which measures antigen-antibody complex formation over the first minute of the reaction, were both considerably more specific for the beta1 component of pregnancy specific beta1 glycoprotein immunoreactivity than the laser nephelometric or electroimmunoassay methods.

Development of a radioimmunoassay for pregnancy-associated plasma protein A and establishment of normal levels in the first trimester of pregnancy.

An accelerated double antibody method has been developed for the radioimmunoassay of pregnancy-associated plasma protein A (PAPP-A) in serum. The workable range for the assay was 0.04-1.8 mg/l of serum. PAPP-A levels were determined in single serum samples from 110 women with prospective normal pregnancies of between 7 and 14 weeks' gestation. The level of pregnancy specific beta 1 glycoprotein (SP1) was also measured in these samples and normal ranges for PAPP-A and SP1 were constructed from the results obtained.

Trial of support treatment with human chorionic gonadotrophin in the luteal phase after treatment with buserelin and human menopausal gonadotrophin in women taking part in an in vitro fertilisation programme.

OBJECTIVE: To evaluate the effect of support with human chorionic gonadotrophin in the luteal phase in women taking part in an in vitro fertilisation programme after buserelin and human menopausal gonadotrophin were used to hyperstimulate their ovaries. DESIGN: Controlled group comparison. SETTING: Outpatient department of a private hospital. PATIENTS: 115 Women with indications for in vitro fertilisation, all of whom had at least one embryo transferred. INTERVENTIONS: After suppression of the pituitary with buserelin the ovaries of all the women were stimulated with human menopausal gonadotrophin on day 4 of the luteal phase. Human chorionic gonadotrophin (10,000 IU) was given to induce ovulation, and oocytes were recovered 34 hours later. Embryos were transferred 46 to 48 hours after insemination. Women who had received the 10,000 IU of human chorionic gonadotrophin on a date that was an uneven number (n = 61) were allocated to receive support doses of 2500 IU human chorionic gonadotrophin three and six days after that date. The remaining 54 women did not receive hormonal support. END POINT: Determination of the rates of pregnancy. MEASUREMENTS and main results--Support with human chorionic gonadotrophin did not significantly alter the progesterone or oestradiol concentrations in the early or mid-luteal phase. The mean (range) progesterone concentrations in the late luteal phase in women who did not become pregnant were, however, significantly higher in those who received support (16(9-110) nmol/l nu 8(4-46) nmol/l), and the luteal phase was significantly longer in this group (14 days nu 12 days). The rate of pregnancy was significantly higher in the women who received support than in those who did not (25/61 nu 8/54). CONCLUSIONS: When buserelin and human menopausal gonadotrophin are used to hyperstimulate ovaries support with human chorionic gonadotrophin in the luteal phase has a beneficial effect on in vitro fertilisation.