Cell suspensions were prepared from human corpora lutea obtained during the mid-luteal phase. Progesterone production was assessed after short-term incubation of luteal cell suspensions. Luteal cells were very sensitive to hCG, the concentration required for 50% maximum response being 0.01 i.u./ml, and the response was 5 times higher than the basal production. Oestradiol (1-100 microM) induced a significant dose-related decrease in both basal and hCG-stimulated progesterone production. The A-nor steroidal compounds anordrin and AF-45 reduced hCG-stimulated progesterone production only at the high concentration of 100 microM. The ED50 values were approximately 3 microM, 75 microM and 100 microM for oestradiol, AF-45 and anordrin respectively. Anordrin showed no significant effects on basal progesterone production. In addition, oestradiol markedly inhibited the activity of 3 beta-hydroxysteroid dehydrogenase in luteal cells, expressed by the conversion of pregnenolone to progesterone, but the inhibitory effects of anordrin and AF-45 were negligible or relatively low. The effects of anordrin and AF-45 were different from those of oestradiol on progesterone production by human luteal cells in vitro, indicating that neither substance is likely to be a useful luteolytic agent in women.

SUMMARY.Prolactin has been reported to be present in cervical mucus at concentrations higher than those found in blood. Our initial findings appeared to confirm this and the material fulfilled criteria of validity generally applied when an immunoassay is employed on a new biological matrix, i.e. parallelism and chromatographic identity. Further experiments demonstrated that prolactin concentrations in cervical mucus were less than 40 mUlL and the prolactin-like immunoreactivity originally detected was due to the action of the enzyme bromelin which was used to liquefy the mucus. Bromelin has a similar molecular weight to prolactin and appeared to digest prolactin tracer and reduce its ability to bind antiserum in a manner paralleling the effect of adding pituitary prolactin.Prolactin has been reported to be present in relatively high concentrations in a number of body fluids including amniotic fluid;' rnilk.i semen" 4 and cervical mucus-where it has been suggested that it may alter the receptivity of the mucus to spermatozoa at mid-cycle by altering the concentration of electrolytes."Many studies have shown that in plasma, prolactin, as identified by radioimmunoassay, is present in three different molecular forms:": 7 the smallest (mol. wt. 22 0(0) corresponding to monomeric prolactin, and the larger forms (mol. wt. 50 000 and greater than 100 000 daltons) to dimer and aggregate or precursor respectively. Size heterogeneity of immunoreactive prolactin has been reported in amniotic fluid," cerebrospinal fluid" and seminal plasma. III This study was originally undertaken to confirm that prolactin was present in cervical mucus and to investigate whether it was present in different molecular weight forms.Samples of cervical mucus were obtained from a seminology laboratory attached to an inferility out-patient clinic. These samples had been collected for sperm antibody investigations and had already been treated with bromelin, a peptidase obtained from plants of the pineapple family, 11 in order to liquefy the mucus and make it easier to pipette.Correspondence: S B Sufi. 316During the course of the investigation it became apparent that this enzyme was interferring in the radioimmunoassay for prolactin. This paper is a report of this effect. Materials and methods SAMPLESSamples of mucus were collected, during the periovulatory period, from subjects having regular menstrual cycles who were attending an infertility clinic. They were instructed to abstain from sexual intercourse for 3 days prior to collection. TREATMENT OF SAMPLESThree methods of pretreatment of samples before assay were investigated. All samples were stored at -20°C after liquefaction. Bromelin treatmentOne vial of bromelin (Blood Transfusion Service, Central Laboratory, Amsterdam, Netherlands) was diluted with 2 mL of 0·88% sodium chloride solution to give a stock solution containing ()·5% bromelin. An equal volume of bromelin solution was added to each sample of cervical mucus and the sample was left to liquefy at ambient temperature. Freezing and thaw...