In order to determine differences in absorption of polycyclic aromatic hydrocarbons (PAH) between anatomical sites and individuals, coal-tar ointment was applied to skin of volunteers at various sites. The surface disappearance of PAH and the excretion of urinary 1-OH-pyrene after skin application of coal-tar ointment were used as parameters for dermal PAH absorption. The surface disappearance was determined by the measurement of the fluorescence of PAH on skin. Surface disappearance measurements show low but significant differences in dermal PAH absorption between anatomical sites: shoulder > forehead, forearm, groin, > ankle, hand (palmar site). The average PAH absorption rate constant at different skin sites ranges from 0.036/h to 0.135/h (overall mean: 0.066/h). This indicates that after 6 h of exposure, 20-56% of a low dermal dose of PAH (e.g., about 1.0 ng pyrene/cm2) will be absorbed. The interindividual differences in PAH absorption are small (7%) in comparison with differences between anatomical sites (69%). Results based on the urinary excretion of 1-OH-pyrene are less clear. The site of application of the coal-tar ointment (dose: 2.5 mg/cm2 during 6 h) has no significant effect on the excreted amount of 1-OH-pyrene in urine. It is estimated that after coal-tar ointment application on skin, 0.3-1.4% of the pyrene dose (about 2 micrograms pyrene/cm2) becomes systemically available. For the accurate estimation of PAH uptake through skin of workers, it seems relevant to distinguish different body regions, not only because of the regional variation in percutaneous PAH absorption, but also because of the high dispersal of PAH contamination on skin of workers.

The mechanisms involved in the reduced cycle duration following exposure to the odour of urine were studied in natural and experimental 5-day cyclic female Wistar rats.A decrease in the rate of ovarian progesterone secretion from the morning of dioestrus I to that of dioestrus II was observed in females whose cycle duration was reduced from 5 to 4 days following exposure to the odour of rat urine. No decrease in ovarian progesterone secretion occurred in females maintaining a 5-day cyclicity despite exposure to this odour. An increase in follicular growth was noted in females with cycle duration reduced from 5 to 4 days, when compared with those maintaining a 5-day rhythm. As a result of exposure to the odour of urine no reduced cycle duration occurred in females with cycles lengthened from 4 to 5 days as a result of progesterone injection on dioestrus I of 4-day cycles. Hence the decrease in ovarian progesterone secretion, induced by exposure to the odour of urine, is considered to cause a speeding up in follicular growth, thereby reducing oestrous cycle duration in 5-day cyclic rats.The role of the odour of urine in the regulation of oestrous cycle duration is now well established in the rat. Cooper 8c Haynes ), Cooper et al. (1972) and Purvis et al. (1971 demonstrated in female rats, with lengthened cycles following food restriction, that the presence of the male could result in reduced cycle duration. Likewise, olfactory stimuli may act on normal cyclic female rats. Olfactory bulb deprivation was shown to alter oestrous cycle duration 426

The increase in serum concentrations of LH and FSH after intramuscular administration of LH/FSH-RH was investigated in normal and hypogonadotrophic hypogonadal males. LH and FSH were measured by specific radio-immunoassays. To evaluate the appropriate dose of LH/ FSH-RH for intramuscular administration different doses were administered and with 200 μg an increase in LH and FSH was found comparable to the results obtained by other investigators using intravenous administration. After the initial studies a simple test including two determinations before LH/FSH-RH administration and one 60 min and 120 min after administration was developed and used in all cases. In 12 normal males a significant increase in the serum concentration of both LH and FSH was found averaging 381 % and 148 % respectively 60 min after 200 μg LH/FSH-RH with a slight decrease in LH but not in FSH after 120 min. A positive response similar to that in normal men was observed in 11 hypogonadotrophic hypogonadal patients presenting different clinical pictures. This indicates that in all these patients the hypogonadotrophic state was due to a hypothalamic defect and not to a hypophyseal disorder.