To investigate the effect of changes in sex hormone concentration on muscle strength and the bioavailability of 17-beta oestradiol (oestradiol) and testosterone, seven eumenorrheic females were tested during two phases of the menstrual cycle. Maximum voluntary isometric strength of the first dorsal interosseus muscle was measured during the early follicular and mid-luteal phases of the menstrua...

Three mature nulliparous female leopards were studied for 5 years. During three separate 6-month periods serum oestradiol and progesterone concentrations were measured at weekly intervals. Oestradiol was elevated over 21 pg/ml for 54 weeks during these 3 periods, and 36 oestradiol peaks (65.8 +/- 6.3 pg/ml (mean +/- s.e.m.), range 21-172 pg/ml) were identified. Daily frequency of feline reprodu...

The timing and dosage of oestradiol benzoate injected after weaning was critical with respect to the pattern of behavioural oestrus and the ovarian stimulation achieved; treatment on the day of weaning (Day 0) and Day 1 with 60 micrograms oestradiol benzoate/kg body wt produced poor ovulatory responses and abnormal oestrous behaviour. Treatment on Day 2 with 30 micrograms oestradiol benzoate/kg...

BACKGROUND Oral and transdermal postmenopausal hormone replacement therapy (HRT) affects lipid and glucose metabolism differently, which is of significance in the release of leptin by adipocytes. Moreover, oestrogen and progesterone can stimulate leptin secretion in women of reproductive age. Therefore, we compared the effects of oral and transdermal oestrogen plus progestin regimen on plasma l...

The aim of this study was to determine for the first time in humans, the efficacy of adding a low dose oestradiol to a suboptimally suppressive testosterone dose in a depot hormonal regimen to suppress spermatogenesis in healthy eugonadal men. Twenty-six healthy men were randomized into groups that were treated by a single subdermal implantation of either 600 mg testosterone alone (T; n = 11) o...

Recent studies suggest that oestrogen and progestin receptors may be activated by the neurotransmitter dopamine, as well as by their respective ligands. Because intracerebroventricular infusion of D(1), but not D(2), dopaminergic receptor agonists increases oestrous behaviour in oestradiol-primed rats, we wanted to determine if treatment with oestradiol alters the activity of D(1) receptor-asso...

A specific high-affinity oestradiol-binding protein was characterized in salt extracts of liver nuclei of the developing chick embryo. It is present in very small amounts at day 10 of development and is marginally stimulated by oestradiol injection into the yolk sac on day 8. Injection of oestradiol on day 10 evokes a substantial increase in the nuclear oestradiol-binding activity measured on d...

Breast cancer risk is increased by early menarche and late menopause, suggesting that the long duration of exposure of the breasts to the high levels of ovarian steroids in premenopausal women increases risk. Recent prospective studies have shown that postmenopausal women who develop breast cancer have significantly greater prediagnostic serum concentrations of oestradiol than postmenopausal wo...

A 31 year old woman had her treatment for infertility by in-vitro fertilization (IVF) cancelled because a highly elevated serum concentration of oestradiol was detected, contrary to the clinical picture and that observed by vaginal ultrasound. The immunoassay for measuring oestradiol had been affected by circulating heterophilic antibodies in the form of an elevated immunoglobulin (Ig) G-kappa ...