Axillary pheromones modulate pulsatile LH secretion in humans.

We examined the effect of axillary compounds on pulsatile secretion of serum luteinizing hormone (LH). Axillary compounds were collected from donor women in the follicular phase (FP) and the ovulatory phase (OP) and were treated with isopropyl alcohol (IPA). The recipient was not exposed to either axillary compounds or IPA for the first 4 h and was exposed to FP or OP compounds, or to IPA, during the next 4 h. The frequency of the LH pulse was increased by FP compounds and was decreased by OP compounds, but the LH pulse frequency was not changed by IPA. Therefore, in humans, pheromones may play a role in the modulation of the timing of ovulation by changing the frequency of pulsatile LH secretion.

Menstrual and circadian variations in time perception in healthy women and women with premenstrual syndrome.

A time production test was performed in seven normal females and seven females with premenstrual syndrome (PMS). We used a time production test for six time intervals (6, 12, 24, 36, 48, 60 s). Time production tests were performed at 08:00, 14:00 and 20:00 h in the follicular, early luteal and late luteal phases (LLP), respectively. The results are as follows. (1) Normal females showed diurnal variations in time production only in the follicular phase (FP). In this phase, they overproduced time at 08:00 h suggesting that the interval clock in normal females was slowest in the morning. (2) Normal females showed menstrual variations in time production only at 20:00 h. They overproduced time in the LLP suggesting that the interval clock in normal females was slowest in the LLP. (3) Neither diurnal nor menstrual variation was found in PMS subjects at any menstrual stage or at any time of the day. These results suggest that the interval timing system in normal females is under the control of ovarian steroid hormones and the circadian clock, but the control of ovarian steroid hormone or the circadian clock does not operate in PMS subjects.

Positive relationship between menstrual synchrony and ability to smell 5alpha-androst-16-en-3alpha-ol.

To explore the possibility that compounds which were identified as pheromones in experimental animals mediate human menstrual synchrony, we examined the relationship between menstrual synchrony and the ability to smell putative pheromones, 5alpha-androst-16-en-3alpha-ol (3alpha-androstenol) and 5alpha-androst-16-en-3-one (5alpha-androstenone). When we examined menstrual synchrony among 64 women living together in a college dormitory, we found that 24 (38%) of them became synchronized with room-mates in 3 months. Afterwards, dilution series of 3alpha-androstenol and 5alpha-androstenone and the control odorant (pyridine) were presented to the 64 women and sensitivity to the odors was compared between synchronized and non-synchronized women. No difference was found between the two groups of women in the detection threshold for pyridine, indicating that general olfactory ability did not differ between them. The detection threshold for 3alpha-androstenol of synchronized women was significantly lower than that of non-synchronized women, but no difference in the threshold for 5alpha-androstenone was found between synchronized and non-synchronized women. These results indicate that the women who showed menstrual synchrony had a higher sensitivity to 3alpha-androstenol but not necessarily to 5alpha-androstenone.

Effects of 5alpha-androst-16-en-3alpha-ol on the pulsatile secretion of luteinizing hormone in human females.

We examined the effects of 5alpha-androst-16-en-3alpha-ol (3alpha-androstenol) on pulsatile luteinizing hormone (LH) secretion in human females. The frequency of the LH pulse in the follicular phase was decreased by exposing the women to 3alpha-androstenol.

Effects of irradiation on the sensitivity of melatonin release to norepinephrine in cultured pineal bodies of rats.

We measured levels of basal and norepinephrine (NE) -induced melatonin release in cultured pineal bodies of rats just after and 2 days after irradiation (20 or 200 Gy) or sham-irradiation. On the day of irradiation, basal and NE-induced melatonin release were not affected by irradiation. Two days after irradiation, basal melatonin levels in both irradiated groups were significantly lower than those in control group, whereas NE-induced melatonin levels in the irradiated groups were higher than those in the control group. These results suggested that irradiation decreases basal melatonin synthesis in pineal glands but that melatonin response to NE is increased after irradiation.