To elucidate the effect of smoking on estrogen metabolism, we examined 136 postmenopausal women treated for one year with one of three different doses of combined estrogen-progestogen or placebo. The women were grouped according to smoking status, and serum levels of estrone and estradiol were measured before and after treatment. The results showed reduced levels of both estrogens in smokers as compared with nonsmokers in all three dosage groups. This reduction was most pronounced in the high-dose group (4 mg of estradiol), in which the serum levels of estrone and estradiol in smokers were only 50 per cent of those in nonsmokers (P less than 0.001 and less than 0.05, respectively). In contrast, no significant changes could be demonstrated in the corresponding placebo groups. Moreover, it was possible to demonstrate significant inverse correlations between the number of cigarettes smoked daily and the changes in the levels of serum estrone and estradiol, respectively, (P less than 0.001). This study suggests that an increased hepatic metabolism of estrogens results in lower estrogen levels among postmenopausal smokers. This may contribute to the reported risk of osteoporosis among smokers.

ing of the lesions would have been more rapid in the drugtreated group.A long-term follow-up of patients with pain lasting longer than the 28-day study was carried out. This showed that the group was significantly older rthan those patients whose pain went during the 28-day observation period and the final disappearance of pain was at about the same time in both the control and treated groups.I thank the following family doctors who collaborated in the studv: Drs.

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The precision and reporducibility of three different clearance methods as used in clinical routine assessment of glomerular filtration rate (GFR) were investigated in 51 patients: total [51Cr]EDTA plasma clearance (E); 24-hr endogenous creatinine clearance (C); and creatinine clearance estimated from the plasma creatinine concentration, weight, and sex- and age-dependent mean creatinine excretion rate (c). The precision and reporducibility (coefficient of variation) for single determinations were, in patients with E greater than 30 ml/min, 5.5 and 4.1% (E); 26.9% (C); and 23.2 and 11.0% (c). The corresponding figures for E less than 30 ml/min were 11.6 and 11.5% (E); 21.9% (C); and 21.4 and 6.5% (c). The precision of C could not be ameliorated by excluding single deviating determinations, but only by excluding patients for whom the precision of 15.5% for mean of three determinations of C (total material) could be reduced to 10% by excluding 25% of the patients. The present data indicate that E in most cases is the method of choice for assessment of GFR in clinical routine work. For changes in renal function, especially at low functional levels, c may be of value.

SUMMARYThe bone mineral content (BMC) and body height were measured in 301 normal children and adolescents aged 7-20 years, and in 8 boys with constitutional delayed puberty aged 14-17 years. Serum testosterone was measured in the last group as well as in a subpopulation of the normal children and adolescents. The growth spurt, which coincided with a steep increase of serum testosterone in boys, indicated a great change in skeletal growth and mineralisation in both sexes. After the growth spurt, linear growth slowed down considerably while bone mineralisation rose steeply. When low levels of serum testosterone were maintained, as in delayed puberty, these combined changes of skeletal growth and mineralisation did not occur. It is suggested that gonadal hormones are the true initiators of the short-lived growth spurt as well as of prolonged acceleration of bone mineralisation.