Cervical ripening with combinations of vaginal prostaglandin F2-alpha estradiol, and relaxin

The first of a 2-part trial consisted of a double-blind randomized pilot study in which 4 groups of 10 patients near term received 1 of the following hormonal combinations in a vaginal gel 15 hours before surgical induction of labor: 1) prostaglandin F2 alpha (PGF2 alpha) and relaxin; 2) relaxin and estradiol; 3) estradiol and PGF2 alpha; and 4) relaxin, estradiol, and PGF2 alpha. In each group the mean cervical score improved after treatment; the relaxin/PGF2 alpha combination was associated with the greatest improvement in cervical score (4.8). The highest incidence of subsequent labor was also seen in the relaxin/PGF2 alpha group (40%). However, with the exception of the latter group, the clinical effects of these hormonal combinations were neither greater nor smaller than the previously published effects of these hormones used individually in similar circumstances. The second part of the study further explored the possibility of an additive effect of relaxin and PGF2 alpha in combination as suggested by the pilot study, and an additional 40 patients were given this combination. Analysis of these larger numbers showed no additive effect when these hormones were used in combination compared with when they were used individually. Thus, in the circumstances described, there is no clinical advantage to the concurrent administration of any combination of relaxin, PGF2 alpha and estradiol with regard to cervical ripening and/or the initiation of parturition.

Relaxin purification from human placental basal plates

A crude relaxin preparation has been obtained from the basal plate region of electric cesarean section human placentae, as well as normal term placentae. The relaxin isolated has different charge properties by ion exchange chromatography from porcine relaxin, although it is of approximately the same molecular size. The most potent fraction obtained has approximately 0.7% of the immunoactivity of purified porcine relaxin when compared with porcine relaxin in a RIA based on porcine material, suggesting significant amino acid sequence differences between the putative human relaxin and its porcine counterpart.

Ripening of the human cervix and induction of labour with purified porcine relaxin

In a randomised double-blind trial 10 of 30 patients given 2 mg of intravaginal purified porcine relaxin on the evening before surgical induction of labour went into labour before the proposed induction. Of 30 control patients, none went into labour. Of the 30 patients treated with relaxin, 25 had improved cervical scores after treatment and significantly fewer required augmentation in labour with intravenous oxytocin than the control group. Administration of relaxin was associated with very little increase in uterine activity and no side-effects. The trial shows that exogenous relaxin causes cervical ripening and can initiate parturition. Endogenous relaxin may have a similar role.

Plasma IgA, IgG and IgM and their relationship to breast cancer in British, Japanese and Hawaiian-Japanese women

The plasma levels of immunoglobulins IgA, IgG and IgM have been measured in 35 British, 44 Hawaiian-Japanese and 37 Japanese healthy adult women. Previous investigations showed that the mean levels of all three immunoglobulins were higher in Japanese than in British normal women. The present study finds that Hawaiian-Japanese women have "Japanese" levels of IgA, "British" levels of IgM and are intermediate for IgG. Thus, plasma IgM concentrations correlate with breast cancer incidence rates in the three racial groups and the reduced amounts of plasma IgM found in Japanese patients with breast cancer support this association.

Human chorionic gonadotropin beta-subunit--like immunoreactive material in the plasma of women wearing an intrauterine progesterone contraceptive system

A systematic study of the presence of human chorionic gonadotropin beta-subunit--like (hCG beta-like) material in the plasma of one woman sampled daily throughout one menstrual cycle and in nine women studied on a selected bleeding schedule has been carried out. Peaks of immunoreactive hCG beta-like activity were found in the follicular and luteal phases of these menstrual cycles which could not be explained by a cross-reaction of luteinizing hormone (LH) in the plasma. The same nine women were studied again 1 month after the insertion of the intrauterine progesterone contraceptive system (IPCS) and again 6 to 8 months later. Although the presence of hCG beta-like immunoactivity correlated with LH values in the cycles studied, there was a significant decrease in its presence 1 month after IPCS use and a highly significant decrease after 6 to 8 months of use.

Specificity of radioimmunoassays for relaxin

The specificities of two radioimmunoassays (RIA) for relaxin, based upon crude porcine relaxin (NIH-R-P1; RIA I) and a highly purified porcine relaxin (RIA II) have been studied concurrently using purified hormones and plasma samples. A labelled fraction, selected from radio-iodinated NIH-R-P1 and used in that RIA, was also bound to antiserum raised to the highly purified relaxin. Hence a third RIA was possible in which both the crude and the purified relaxins inhibited in the ng/ml range. Porcine insulin and the connecting peptide of porcine proinsulin did not inhibit any of the assay systems whereas porcine proinsulin did inhibit in each assay at the microgram/ml range. Concurrent measurements by assays I and II have been made in sheep plasma obtained during both delivery of the lamb and suckling. The peak values obtained by assays I and II are 3 and 6 min out of phase during suckling and delivery respectively; the NIH-R-P1 relaxin immunoactivity appearing first. The plasma inhibition curves of both appear to be the sum of individual contributions from relaxin and relaxin-like peptides, such as prorelaxin and its fragments, as seen by different antisera. Both assays, however, give qualitatively similar indices of relaxin immunoactivity. The RIA developed for the more purified peptide would be expected to yield a better quantitative estimate of relaxin secretion but this, like specificity, cannot be shown absolutely.

Pulmonary insulin responsivitiy: in vivo effects of insulin on the diabetic rat lung and specific insulin binding to lung receptors in normal rats

Adult rats were rendered diabetic by a single iv injection of streptozotocin (70 or 75 mg/kg). In these rats, serum insulin fell to minimal levels during the 48 h following drug treatment, and this was roughly paralleled by a progressive decrease in the ability of the lung to oxidize glucose. The addition of insulin to diabetic rat lung slices in vitro had no restorative effect on the depressed glucose oxidative rate during a 2 h incubation period; however, two daily treatments of the rats with 1 unit of protamine, zinc insulin completely restored lung glucose oxidation rate to normal, without significantly reducing the hyperglycemic state of the rats. An examination of the temporal changes in glucose utilization by the rat lung after acute insulin treatment revealed that the diabetic lung responded directly to serum levels of insulin, whereas the normal lung appeared to be unaffected by serum insulin levels as hihg as 87 ng/ml. The reduced rate of glucose oxidation in the diabetic lung was apparent after perfusion of the lung with glucose-free medium, and was characterized by a significant reduction in Vmax without an alteration in Km. This was attended by a depressed ability of the lung to incorporate [3H]leucine into protein and an increased ability to produce lactate, but hexose monophosphate shunt activity was normal. Specific receptors for insulin have been identified and partially characterized in crude membrane preparations of normal rat lung. The interaction of insulin with these receptors was rapid, reversible, saturable, and was dependent upon time and temperature. The binding of labeled insulin was inhibited by low concentrations of unlabeled insulin and by high concentrations of proinsulin, whereas it was unaffected by the presence of glucagon, gastrin, prolactin, ACTH, or growth hormone in microgram amounts. These observations suggest that insulin regulates the transport and utilization of glucose in the rat lung, and that this tissue contains specific receptors for insulin.

Hormonal evaluation of the intrauterine progesterone contraceptive system

Nine women were studied for one menstrual cycle prior to the insertion of an intrauterine progesterone contraceptive system (IPCS) delivering 65 microng progesterone/day into the uterus and again at 1 month after its insertion. Eight of these women were again studied between 6-8 months after the insertion of the IPCS. Luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol-17beta, progesterone, prolactin and relaxin were measured in each plasma sample. The data from each study were combined according to the day of the LH peak. Ovulation occurred in all the cycles studied in spite of an elevation in plasma estradiol-17beta and a depression of prolactin and relaxin immunoactivities at the 6-8 month follow up. Menstruations noted at the 6-8 month of use occurred while levels of estradiol-17beta and progesterone were elevated.

Secretion of prolactin and luteinizing hormone at oestrus in the ewe

Studies of the effect of mating on the release of prolactin over a 47-h period from the onset of oestrus in the ewe are presented. Surges of prolactin occurred around the time of pre-ovulatory luteinizing hormone release, and in some instances copulation appeared to result in an additional surge of prolactin secretion.

Pituitary function after yttrium implants as measured by plasma growth hormone levels

Plasma growth hormone (GH) levels during insulin hypoglycaemia were measured in 30 women with implants of 90Y in the pituitary for advanced breast cancer. There was evidence of continued pituitary activity in six patients (20%), the rise in plasma GH level being greater than 4 ng/ml during hypoglycaemia. Thirteen patients (43%) were regarded as having complete ablations because they had no GH response and a fasting level of less than 4 ng/ml. In the remaining 11 patients (37%) there was no rise in the GH level during hypoglycaemia, but there were significant fasting levels. From the post-mortem evidence it was concluded that these patients also had adequate ablations.

This test is shown to be of more value in estimating residual pituitary function than routine tests of thyroid or adrenal function.

Sequences of pituitary and placental lactogenic and growth hormones: evolution from a primordial peptide by gene reduplication

Human placental lactogen has been found to resemble human pituitary growth hormone very closely in amino acid sequence, about 80% of the residues examined being identical in the two molecules when a revised sequence for growth hormone is used as the basis for comparison. The structural features responsible for the differing biological potency of the two hormones may therefore reside in rather limited regions of primary structure. The observation of internal sequence homologies within the pituitary growth hormone and prolactin and the placental lactogen molecules suggests that these polypeptide hormones may have evolved by genetic reduplication from a smaller common ancestral peptide. This finding directs further attention to subfragments of these molecules as possible possessors of intrinsic somatotrophic and lactogenic activity.

Radioimmunoassay of a human pituitary prolactin in plasma

A protein fraction with prolactin bioactivities was obtained from the culture medium of human fetal pituitary tissue in long term cultures and termed Pasteels human prolactin (PHP) for convenience. An antiserum was prepared against this human prolactin and used to develop a radioimmunoassay for the material in human plasma. The antigen available (220 µg)was tested against antisera to human growth hormone and to human placental lactogen and in radioimmunoassays for these hormones. The results suggested that the human prolactin fraction contained some immunoreactive human growth hormone (1%). The resulting antibodies in the antihuman prolactin serum could be neutralized by the addition of human growth hormone. The human prolactin also generated antibodies, binding ¹³¹I-labelled human prolactin, which were not neutralized by human growth hormone. This binding was inhibited by plasma from a normal male, 2 normal females and by plasma from a lactating woman after breast feeding. An increase in plasma concentration of the inhibitor, immunologically similar to the human prolactin fraction, was obtained after phenothiazine injection. In the 7 plasma samples tested for human prolactin only 1 contained a detectable concentration of immunoreactive growth hormone. Immunoreactive human placental lactogen (human chorionic somatomammotropin) or any material cross-reacting with anti-HCS serum was undetectable in these plasma samples by a sensitive radioimmunoassay. It is suggested that human plasmas contain detectable amounts of a material immunologically similar to a prolactin fraction isolated from tissue cultures of fetal pituitaries. The fraction and the plasma inhibitor are distinguishable by immunoassay from human growth hormone and from human placental lactogen.

Radioactive implants of the pituitary for endocrine disease

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Plasma prolactin in goats measured by radioimmunoassay: the effects of teat stimulation, mating behavior, stress, fasting and of oxytocin, insulin and glucose injections

Results are reported of measuring prolactin in goatplasma by a radioimmunoassay.Changes in concentration in plasma prolactin over time scales from minutes to hours were noted in animals not subject to experimental stimuli. It is presumed that these changes reflect the rapid removal of prolactin from plasma (<i>t</i> ½ 19 min) and the secretion of prolactin in response to unknown internal stimuli. Stimuli are reported which cause rises in plasma concentration suggestive of bursts of secretion from the pituitary. Copulation, in both males and females, sexual excitement in males and milking caused the largest increases in plasma concentration. Oxytocin injections and mild stress caused significant but smaller increases in plasma prolactin sometimes seen as a rise in jugular vein concentrations only. Plasma prolactin fell on fasting and after insulin and it rose on refeeding, but there was not a direct correlation with changes in blood glucose concentration.

Radioimmunoassay for ovine, caprine and bovine prolactin in plasma and tissue extracts

1. A radioimmunoassay for ovine prolactin is described based on the inhibition of the reaction between (131)I-labelled ovine prolactin and guinea-pig or rabbit antiserum to ovine prolactin. The extent of the reaction after a 4-day incubation period is determined by chromatoelectrophoresis or by adsorption of unchanged (131)I-labelled ovine prolactin on charcoal. The sensitivity is equal to 5.9ng. of prolactin/ml. of plasma with chromatoelectrophoresis, or 0.2ng. of prolactin/ml. of tissue extracts with the charcoal separation. 2. A complete cross-reaction demonstrated between ovine prolactin and caprine pituitary extracts allows the assay to be used to measure caprine prolactin. The partial cross-reactions between ovine prolactin and bovine prolactin and between ovine prolactin and bovine pituitary extract differ, and an alteration in the immunological activity of bovine prolactin during its isolation is suggested. Bovine prolactin in plasma may be measured against a bovine pituitary extract as standard. No cross-reactions were demonstrated with pituitary extracts from a number of other species. The extent of the contamination of ovine and bovine growth hormone preparations by their respective prolactins is shown. 3. Dilutions of ovine and caprine plasma inhibit the reaction between (131)I-labelled ovine prolactin and antiserum with the same characteristics as ovine prolactin. 4. The immunoreactive material in plasma fractionates on Sephadex G-200 and in sucrose density gradients as a single peak similar to that shown by freshly dissolved ovine prolactin. There is no evidence that ovine prolactin is bound to a plasma protein. 5. By suppressing prolactin secretion and assaying serial samples of plasma thereafter it is shown that the immunological activity of the surviving hormone becomes progressively altered with time. It is suggested that this alteration is usually not detected but introduces an element of uncertainty into the quantitative but not the qualitative value of the measurements obtained by reference to standard ovine prolactin.