Effects of cigarette smoking on cyclic AMP, cyclic GMP, dopamine beta-hydroxylase and nicotine in human plasma and urine during water diuresis

In vitro activation of amphibian dermal melanocytes by nicotine

Epidemiologic investigations have shown that nicotine could be a factor causing oral melanin pigmentation in man. Nicotine was therefore tested on amphibian skin melanocytes. Cell reactions were registered by spectrophotometry, in vitro light microscopy, photomicrography and light and electron microscopy. It was found that dermal melanocytes in the toad Bufo bufo and the frog Rana arvalis were activated by nicotine and that this activation was not mediated via beta-adrenergic receptors in melanocytes.

Elevated nicotine levels in patients undergoing hemodialysis. A role in cardiovascular mortality and morbidity?

The incidence of cardiovascular disease in patients with end-stage renal disease undergoing long-term maintenance hemodialysis is excessively high. The reason for this excess morbidity and mortality has remained unclear. Cigarette smoking is one factor that has been associated with increased cardiovascular risk. To learn more about the effects of tobacco smoking in these patients, nicotine levels were assayed in the serum of 10 patients with end-stage renal disease undergoing maintenance hemodialysis. Specimens were obtained before and after smoking one cigarette and following dialysis or an equivalent period in control subjects. Serum nicotine levels (+/-SEM) in control subjects measured 19.0 +/- 7.2 ng/ml initially, 36.1 +/- 8.2 ng/ml after smoking, and 9.3 +/- 3.5 ng/ml after a period of 4.35 hours. These compare with respective values of 76.6 +/- 16.8 ng/ml (p less than 0.004), 132.9 +/- 19.7 ng/ml (p less than 0.001), and 51.9 +/- 10.5 ng/ml (p less than 0.001) in patients undergoing hemodialysis. These data demonstrate markedly higher nicotine levels in hemodialysis patients compared with control subjects, which may have serious implications regarding morbidity and mortality.

Urinary excretion of cyclic nucleotides and principal electrolytes in healthy humans of different ages

Urinary excretion of cyclic AMP, cyclic GMP, inorganic phosphorus, calcium, sodium, potassium and creatinine was measured in 138 healthy male and 104 healthy female humans from 2 to 68 years old. The range of cyclic nucleotide excretion was as follows: cyclic AMP (mumol/day), 1.01-10.89; cyclic GMP (mumol/day), 0.13-2.00; cyclic AMP (mumol/g creatinine), 1.52-8.93; cyclic GMP (mumol/g creatinine), 0.11-1.87. The 242 volunteers were grouped into seven classes according to age: A, 2-9 years old; B, 10-19; C, 20-29; D, 30-39; E, 40-49; F, 50-59 and G, 60-68. Average excretion (mumol/day) of cyclic AMP in class A (2.62 +/- 0.29 for males and 2.30 +/- 0.18 for females) was significantly smaller than that in other classes (4.59 +/- 0.12 for males and 3.90 +/- 0.13 for females) (p less than 0.01). Such a significant difference was not observed in cyclic GMP excretion. In terms of mumol/g creatinine, however, average excretion of both cyclic AMP and cyclic GMP in class A was greater than that in other classes. The amounts of urinary cyclic AMP and cyclic GMP (mumol/day) were correlated with age in the subjects from 2 to 16 years. A reverse correlation between the amounts of both nucleotides (mumol/g creatinine) and age was found in the young subjects. No correlation between the excretion of either urinary cyclic nucleotide and age was found in adults. A significantly positive correlation between cyclic AMP (mumol/day) and inorganic phosphorus (g/day) was found (r = 0.50 for males and 0.56 for females) (p less than 0.01). This correlation suggests that urinary cyclic AMP might reflect the activity of parathyroid hormone in normal humans. There was no significant correlation between cyclic GMP and electrolytes tested. The above results are considered to provide basic data for clinical evaluation of relevant disorders.

Evaluation of smoking-induced effects on sympathetic, hemodynamic and metabolic variables with respect to plasma nicotine and COHb levels

The effect of smoking cigarettes containing 1.5 mg and 0.08 mg nicotine per cigarette and of sham-smoking was studied in six healthy habitual smokers. Levels of carboxyhemoglobin (COHb) and plasma nicotine were measured simultaneously with hemodynamic variables, such as heart rate and blood pressure, and with the metabolic parameters, plasma DBH, cortisol, blood glucose, lactate and free fatty acids. All variables, with the exception of COHb are dose related to plasma nicotine levels. Blood pressure, heart rate and lactate show simultaneous peaks together with maximal nicotine levels, while DBH and cortisol, blood glucose and free fatty acids show a delayed reaction compared to nicotine concentrations. No effects of COHb, even with levels up to 5.6 +/- 0.5% have been observed on the variables investigated. These results demonstrate, that it is nicotine which induces considerable hemodynamic and metabolic alterations after smoking.

Lack of correlation between serum dopamine-beta-hydroxylase activity and blood pressure in middle-aged men

The activity of serum dopamine-beta-hydroxylase (DBH) was measured in 1194 asymptomatic middle-aged men with diastolic blood pressure ranging from 75 to 125 mm Hg during the baseline examination of a multifactorial intervention program for primary prevention of coronary heart disease. No correlation was present between serum DBH activity and systolic (r = -0.01, NS) or diastolic (r = +0.02, NS) blood pressure. No significant differences in serum DBH activity was observed between individuals with blood pressure in the lower, middle or upper deciles. Serum DBH activity was similar in subjects with normal blood pressure, in individuals with widely fluctuating blood pressure and in patients with fixed hypertension. The results suggest that serum DBH activity cannot be used as an aid in the diagnosis of essential hypertension of middle-aged men.