The effects of short-term treatment with levamisole on cytokines in volunteers and cancer-patients.

In search for clues to the potential immunomodulating mechanism of action of levamisole which might be used as monitoring parameters, we have determined a variety of cytokines in the peripheral blood of volunteers and carcinoma patients before and after a single or a 3-day-treatment with 150 mg/day. In cancer patients no changes could be detected 4 days after a 3-day-treatment course in the levels of TNF-alpha, IL-1beta, IL-2 or IL-6. In a placebo-controlled volunteer study the same treatment did not affect the levels of beta2-microglobulin, IL-1beta, IL-1alpha, IL-2 or IL-6. However, 24hr after the last treatment the concentration of neopterin was slightly but significantly increased and the concentration of soluble IL-2 receptors decreased. A single treatment failed to produce such an effect. It is suggested that the measurement of neopterin and soluble IL-2 receptors may provide useful information in future trials.

Potency and selectivity of the aromatase inhibitor R 76,713. A study in human ovarian, adipose stromal, testicular and adrenal cells.

The effects of R 76,713 on steroidogenesis were studied in primary cultures of four different human cell types, i.e. ovarian granulosa cells, adipose stromal cells, testicular cells and adrenal cells. In human granulosa cells aromatization of [1 beta, 2 beta-3H]androstenedione (as measured by the release of tritiated water) showed a Km (Michaelis constant) of 78 nM. R 76,713 competitively inhibited aromatization with a Ki (dissociation constant of the enzyme-inhibitor complex) of 1.6 nM. In human adipose stromal cells aromatization was measured by following the conversion of androstenedione to estrone and 17 beta-estradiol. In this system a Km for aromatization of androstenedione of 10.8 nM was found. R 76,713 again showed competitive kinetics with a Ki-value of 0.14 nM. In human testicular cells the synthesis of the androgens testosterone, androstenedione and dehydroepiandrosterone was only inhibited by drug concentrations exceeding 10(-6) M. At 10(-5) M of R 76,713, steroid concentrations were lowered to 56, 64 and 81% of the control for testosterone, androstenedione and dehydroepiandrosterone respectively. Concomitantly, a slight increase in the levels of pregnenolone (138% of the control) and progesterone (133% of the control) was seen. In human adrenal cells the synthesis of cortisol and aldosterone was slightly affected by R 76,713 also at concentrations exceeding 10(-6) M. At 10(-5) M of R 76,713 the concentrations of cortisol and aldosterone were lowered to respectively 59 and 51% of the control. At the same drug concentration the precursors 11-deoxycortisol and 11-deoxycorticosterone rose to 189 and 147% of the control. These results show that in primary cultures of human cells, R 76,713 is a very potent aromatase inhibitor with a selectivity of at least 1000-fold compared to other steps in steroidogenesis.

Comparative effects of etomidate and its fluoro analogue, R 8110 on testicular, adrenal and ovarian steroid biosynthesis.

The effects, of etomidate and of its fluoro analogue, R 8110, on adrenal, testicular and ovarian steroid biosynthesis were compared using cultures of guinea-pig adrenal, rat adrenal capsular, rat testicular and rat ovarian granulosa cells. At a concentration of 100 nM, etomidate inhibited the adrenal 11-hydroxylation of glucocorticoid and mineralocorticoid biosyntheses, producing a decrease in cortisol and corticosterone and an accumulation of 11-deoxycortisol and 11-deoxycorticosterone in guinea-pig adrenal and rat capsular adrenal cell suspensions, respectively. At higher concentrations (greater than 10(-6) M), etomidate also inhibited ovarian oestradiol production, testicular androgen formation and ovarian progesterone synthesis. The latter action suggests an effect on ovarian aromatase, on testicular 17 alpha/17,20-lyase activities and finally on cholesterol side-chain cleavage. The fluoro analogue of etomidate, R 8110, was ten times less potent as an inhibitor of 11-hydroxylation and affected progesterone formation only slightly in adrenal cell suspensions. Testosterone production was less affected by R 8110 than by etomidate. The increase of progestins suggests that the 17 alpha/17,20-lyase activities are the most sensitive testicular enzymatic reactions to R 8110. For inhibition of ovarian oestradiol production, R 8110 was twenty times more potent than etomidate.