Effect of short-term infusion of recombinant human relaxin on blood pressure in the late-pregnant rhesus macaque (Macaca mulatta).

OBJECTIVE: To test a recombinant human relaxin preparation, developed for potential therapeutic application, for possible hypotensive actions in near-term pregnant rhesus monkeys. METHODS: Groups of four females received 1-hour intravenous infusions of 0, 0.1, or 2.0 mg recombinant human relaxin/kg on gestation day 147 (term = 165 days). Maternal heart rate, electrocardiogram, and diastolic, systolic, and mean arterial pressure; and fetal heart rate were monitored before, during, and after the infusion. After spontaneous delivery, physical, neurobehavioral, and physiologic examinations were conducted on the newborn. RESULTS: No effects of recombinant human relaxin were detected by statistical analysis or examination of data records. CONCLUSION: Intravenous infusion of up to 2.0 mg recombinant human relaxin/kg in conscious pregnant rhesus monkeys had no effect on maternal cardiovascular indices or fetal heart rate.

The relationship between hCG and relaxin secretion in normal pregnancies vs peri-implantation spontaneous abortions.

OBJECTIVE: We determined the ovarian response to human chorionic gonadotrophin (hCG) in terms of relaxin and progesterone secretion during the peri-implantation period of normal and failing pregnancies. We wished to test the hypotheses that relaxin production in failing pregnancies is different from that in normal pregnancies, that relaxin is a reliable, quantitative indicator of the biological activity of endogenous hCG, and that relaxin is a useful predictor of peri-implantation spontaneous abortions. DESIGN: Daily blood samples were collected in a prospective longitudinal study from insemination patients. PATIENTS: Women undergoing artificial insemination in natural cycles with non-frozen donor semen at a University clinic. MEASUREMENTS: Serum LH, hCG, relaxin and progesterone were measured and the relationship between hCG and the ovarian hormones was evaluated in the peri-implantation period of normal pregnancies and spontaneous abortions. RESULTS: Nine of 23 conceptive cycles resulted in a spontaneous abortion between 16 and 70 days after the LH peak. In all normal and failing pregnancies there was a close qualitative relationship between hCG secretion and relaxin production. Six of nine failing pregnancies were associated with abnormally low hCG secretion. Six of the spontaneous abortions were associated with rates of relaxin secretion which were higher than the mean of 14 normal pregnancies. No such alterations in progesterone concentrations were observed. In cases where hCG was extremely low, the quantitative relationship between hCG and relaxin was different from that in cases of normal hCG concentrations. CONCLUSIONS: There is a close temporal relationship between the secretion of trophoblastic hCG and ovarian secretion of relaxin in the peri-implantation period of normal and failing pregnancies. In failing pregnancies there is substantial variability in the quantitative relationship between relaxin and hCG, indicating that relaxin is not a reliable quantitative indicator of hCG bioactivity. Contrary to previous reports, relaxin concentrations in failing pregnancies tended to be higher than or equal to concentrations in normal pregnancies until the loss was imminent. Because of this relaxin is not a useful predictor of peri-implantation spontaneous abortions.

Serum relaxin concentrations in patients with out-of-phase endometrial biopsies.

When luteal phase relaxin concentrations were summed to give an integrated measure (pg/mL per cycle), relaxin was found to be significantly lower in those cycles with an out-of-phase endometrial biopsy. In addition, peak relaxin concentrations were lower in out-of-phase cycles compared with normal cycles. These data indicate that relaxin secretion may be related to normal luteal function and suggest that shortening of the luteal phase results in reduced relaxin production. Measurement of circulating relaxin may prove to be useful in making the diagnosis of out-of-phase biopsy and needs to be assessed for its usefulness in diagnosing abnormal luteal function.

Relationship of serum estradiol and progesterone concentrations to the excretion profiles of their major urinary metabolites as measured by enzyme immunoassay and radioimmunoassay.

Paired daily blood and urine samples were collected from 10 apparently healthy premenopausal women to compare the hormone profiles of estradiol (E2) and progesterone in serum with those of estrone conjugates (E1Conj) and pregnanediol-3-glucuronide (PdG) in urine. Serum hormones were measured by radioimmunoassay (RIA) kits, whereas the urinary steroid metabolites were assessed by both RIA and enzyme immunoassay (EIA). RIA and EIA values for urinary E1Conj and PdG were not different, and both methods produced urinary profiles that paralleled the profile of the parent steroid in serum. However, the simplicity, flexibility, and economy of EIA will make this method more widely applicable. Mean E1Conj values lagged behind concentrations of serum E2 by one day or less, whereas daily urinary PdG profiles lagged behind serum progesterone by one to two days. Mean urinary profiles of E1Conj were similar whether or not creatinine was used to adjust for urine volume; however, creatinine indexing was beneficial when urinary profiles in individual cycles were compared with changes of serum E2.

Relaxin in the peri-implantation period.

The time of appearance of relaxin in peripheral blood was determined in conceptive and non-conceptive cycles using a sensitive and specific double-antibody enzyme-linked immunoassay for human relaxin. For study of relaxin in early pregnancy, daily plasma samples were collected from women receiving artificial insemination of donor semen. The day of ovulation was determined by daily LH monitoring and ultrasound observation. In three conceptive cycles, relaxin was significantly elevated over baseline 9-10 days following the LH peak. Relaxin concentrations quickly rose over the next 15 days of observation to over 800 pg/ml. Relaxin was observed to increase 1 to 2 days prior to the first detectable increase in plasma hCG as measured by enzyme-linked immunosorbent assay. To compare the relaxin profile in conceptive cycles with normal luteal phase concentrations, relaxin was also measured in daily plasma samples collected from women contracepting with barrier methods, bilateral tubal ligation, or abstinence. A small but consistent rise in relaxin in the late luteal phase was observed in nine of eleven women, which began 6-9 days after the LH peak, averaged approximately 50 pg/ml, and was declining by the next menses. It is concluded that a small but measurable rise in plasma relaxin is associated with the normal luteal phase and that relaxin secretion is accelerated around the time that hCG is first detected in conceptive cycles. This acceleration of relaxin secretion which is associated with the onset of hCG may provide additional evidence for identification of transient early pregnancy.

The effects of insulin and insulin-like growth factors-I and -II on estradiol production by granulosa cells of polycystic ovaries.

The objective of this work was to examine the effects of insulin-like growth factors (IGFs) on estradiol (E2) production by granulosa cells obtained from ovaries of patients with polycystic ovary disease (PCO). Granulosa cells, isolated from ovaries of three PCO patients, were cultured in serum-free medium containing either androstenedione alone (10(-7) M) or androstenedione plus graded doses of FSH, IGF-I, IGF-II, and/or insulin. At the end of the culture period (2, 4, or 6 days) E2 levels in the medium were measured by RIA. The results from each patient were similar, and therefore, the data were pooled. In the 6-day time-course experiments, the control (untreated) cells produced relatively high levels of E2 at 2 days; however, none was detected thereafter. Treatment with FSH (30 ng/mL) stimulated E2 production 4-fold at 2 days, but the stimulatory effects of FSH were not sustained during culture. IGF-I at 30 ng/mL mimicked the effects of FSH. Concomitant treatment with FSH and IGF-I caused synergistic increases in E2 production (3-, 13-, and 33-fold at 2, 4, and 6 days, respectively). Dose-response studies revealed that FSH and IGF-I stimulated E2 production in a dose-dependent fashion (ED50 of FSH and IGF-I, were 1.1 +/- 0.3 and 7.6 +/- 7.2 ng/mL, respectively). In the presence of a maximally effective dose of FSH (30 ng/mL), the cells appeared to become more responsive to IGF-I (ED50 of IGF-I plus FSH, 1.09 +/- 0.29 ng/mL); however, this effect was not significant (P = 0.086). In the presence of a maximally effective dose of IGF-I (30 ng/mL), the stimulatory effect of FSH on E2 production was dramatically amplified, but the IGF-I did not significantly (P = 0.85) change the potency of FSH (ED50 of FSH plus IGF-I, 1.07 +/- 2.3 ng/mL). Treatment with IGF-II over the concentration range of 0.1-100 ng/mL had no effect on either control or FSH-stimulated E2 production. Treatment with insulin, either alone or together with FSH, increased the levels of E2, but the insulin effects were seen only at the highest doses tested (0.3-10 micrograms/mL). The results in these in vitro experiments with PCO granulosa cells indicate that 1) physiological concentrations of IGF-I are as effective as FSH in stimulating E2 production; 2) IGF-I and FSH act synergistically to control the level of E2 production; and 3) this synergy was not observed with insulin or IGF-II.

CV 205-502 treatment of hyperprolactinemia.

CV 205-502 is a nonergot oral dopamine agonist with specific D2 activity, which has a prolonged suppressive effect on serum PRL and may have fewer side-effects than other dopamine agonists. We treated 26 hyperprolactinemic women with this compound given as a single bedtime (hs) dose for up to 12 weeks. All had gonadal dysfunction, either amenorrhea or oligomenorrhea, and 15 had galactorrhea. The initial and subsequent doses were administered in a randomized fashion; the initial dose ranged from 0.01-0.05 mg, and the dose at 12 weeks ranged from 0.03-0.09 mg. The women were evaluated every 2 weeks, and the dose was increased by 0.02 mg every 4 weeks if the serum PRL level was greater than 20 micrograms/L. Of the 26 women initially enrolled, 24 completed 12 weeks of therapy, and 2 discontinued therapy because of side-effects. Thirteen women (54%) had return of menses, and 12 (80%) had either a decrease in or disappearance of galactorrhea. Serum PRL concentrations decreased to a variable degree in all patients; 13 (54%) achieved a normal serum PRL level (less than or equal to 20 micrograms/L). The mean (+/- SE) pretreatment serum PRL concentration was 129 +/- 34, and it was 29.9 +/- 5.9 micrograms/L after 12 weeks of treatment (P = 0.005). The mean (+/- SE) percent reduction in serum PRL was 66.5 +/- 5.0% (median, 78.0%). A dose response was not demonstrated (r = -0.08; P = 0.70) among the 6 dose groups during the last 4 weeks of therapy. In 5 women, serum PRL levels, measured frequently for 24 h after treatment remained low. Side-effects after the initiation of therapy included nausea, headache, and morning fatigue in 10 women. These symptoms caused 2 women to discontinue therapy; they subsided in the other women. An optimal dose was not determined and will probably need to be determined by titration in each patient. CV 205-502, given once daily, appears to be a safe and effective alternative to other dopamine agonists in the treatment of hyperprolactinemia.

Autogenous free muscle grafts and regeneration in rabbits: a preliminary laboratory study.

From a preliminary study using the flexor digitorum superficialis muscle as an orthotopic free graft in the rabbit forelimb it appears that: (1) viable muscle fibers can be consistently identified in the recipient area, varying from 20 to 100 percent of the normal total fiber count of the FDS graft: (2) viable muscle fibers following grafting appear to be the result of the process of regeneration rather than of survival of original graft fibers; and (3) young rabbits appear to have greater regenerative potential compared with mature rabbits.