Serum Oestradiol-17β in Normal Women

Summary.-Follicular-phase (Day 11) plasma prolactin, and plasma and urinary oestrogen levels of 70 nulliparous nuns were compared with those of 80 of their sisters, of whom 62 were parous. The nuns and their nulliparous sisters did not differ significantly in their prolactin and oestrogen levels. No differences in plasma oestrogens or urinary oestriol ratio were found between the parous and the nulliparous women. However, the mean prolactin level of the nuns and their nulliparous sisters was 3500 higher than that of the parous women in the sample taken 13 h after rising (P < 0-0005), and 24% higher (P <0.01) in the 2nd sample taken 2 h later. The elevation was independent of age, weight, and age at menarche. Age at first full-term pregnancy, at least up to the age of 30, and second or subsequent full-term pregnancies had no further effect on prolactin level. This study suggests that the effect of early first full-term pregnancy in lowering breast cancer risk may be mediated, at least in part, by permanently lowering the level of circulating prolactin.ONE OF THE MOST STRIKING breastcancer risk factors is age at first full-term pregnancy (FFTP): women whose FFTP is before the age of 20 have less than half the breast-cancer risk of nulliparous women (MacMahon et al., 1973). Two theories have been proposed to "explain" how this protective effect of early FFTP is brought about. Cairns (1975) theorized that early FFTP would effectively reduce the number of susceptible breast "stem" cells, while Cole et al. (1976) proposed that the protective effect may be due to a change in the "urinary oestriol ratio". There is no evidence available to either support or refute Cairns's hypothesis, but there is some evidence that early FFTP does increase the urinary oestriol ratio (Cole et al., 1976;Trichopoulos et al., 1980).Prolactin may also play a key role in determining risk of breast cancer (Hill et al., 1976;Malarkey et al., 1977;Pike et al., 1977;Welsch & Meites, 1978) and we were struck by the finding of Vekemans & Robyn (1 975a) in a cross-sectional study that prolactin levels decreased after age 25 in women but not in men. If this decrease with age in women is due to pregnancy, this prolactin change may be a critical part of the protective effect of early FFTP.In this paper we describe our results in comparing the plasma prolactin, and plasma and urinary oestrogen levels of nulliparous and parous women aged in California. METHODSWith the cooperation of a number of Catholic orders in California, we identified Caucasian nuns aged 20-39, who had never been pregnant and who had at least one sister aged 20-39 residing in the continental U.S. We excluded nuns who had had uterine (excluding D&C) or ovarian surgery. We also

Section: Resultsmentioning

confidence: 78%

Elevated levels of prolactin in nulliparous women

Yu¹,

Gerkins²,

Be³

et al. 1981

“…In a previous study (England et al, 1974) (England et al, 1974). The addition of two more since this publication has not None of the subjects studied had a history of gynaecological disease or was taking any hormonal preparation.…”

mentioning

confidence: 93%

“…Measurement of serum oestradiol-173.-Radioimmunoassay of oestradiol-17/3 was carried out by the method described previously (Cameron and Jones, 1972;England et al, 1974). By counting the radioactive supernatant sample (0.5 ml) in 10 ml of a 1 : 1 dilution with Scintillator Grade Xylene of PCS-Liquid scintillation cocktail (Hopkins and Williams, Chadw%Aell Heath, Essex) counting efficiency was rasied to approximately 38%o.…”

mentioning

confidence: 99%

Serum Oestradiol-17β in Women with Benign and Malignant Breast Disease

England¹,

Skinner²,

Cottrell³

et al. 1974

Self Cite

Summary.-Serum concentrations of oestradiol-173 were measured daily throughout one menstrual cycle in 32 normal women, 31 women with benign disease of the breast and 10 with cancer of the breast. The concentrations were found to differ significantly from normal in women with cysts and to a lesser extent in those with cancer of the breast. In 25 normal post-menopausal and in 27 post-menopausal women with cancer repeated assays disclosed consistently low levels of oestradiol-17/f.

“…Serum oestradiol was measured by radioimmunoassay as published elsewhere (England et al, 1974 (Siegel, 1956 Mean concentration for serum oestradiol in adult women (luteal phase): 67-3 ± 1-47 (se mean) pg/ml.…”

Section: Methodsmentioning

confidence: 99%

Ovarian failure following abdominal irradiation in childhood

Shalet¹,

Beardwell²,

Jones³

et al. 1976

106

Summary.-Ovarian function was studied in 18 female patients treated for abdominal tumours during childhood. All received abdominal radiotherapy as part of their treatment and were studied between 1 and 26 years after irradiation. The serum gonadotrophins and oestradiol levels were consistent with ovarian failure in each case but there was a disproportionate elevation in serum follicle stimulating hormone (FSH) when compared to serum luteinizing hormone (LH) in 16. In 2 patients, the radiotherapeutic field extended downwards only as far as the sacral promontory. However, these 2 girls show similar evidence of ovarian failure to that in the other 16.