Cytosol and nuclear estrogen receptors and cytosol progesterone receptors were measured in 17 primary breast tumors and compared with sex chromatin frequencies. In cases with sex chromatin frequencies of greater than 20% there were 7/7 tumors with cytosol estrogen and progesterone receptors, 6/7 with cytosol and nuclear estrogen receptors, and 6/7 with all 3 receptors. This high proportion of receptor positive cases was not observed at lower sex chromatin frequencies. Sex chromatin frequencies in all the cytosol estrogen and progesterone receptor positive tumors were significantly higher (p less than 0.05) than in the other groups. Our results suggest a possible association between the presence of steroid hormone receptors and sex chromatin frequencies of greater than 20%.

Breast Neoplasms↗

PubMedDate not supplied

Inhibition of hepatic microsomal cytochrome P-450 dependent monooxygenation activity by the antioxidant 3-tert-butyl-4-hydroxyanisole.

The efficacy of 3-tert-butyl-4-hydroxyanisole (BHA) as a chemopreventive agent against chemically induced cancer or toxicity may involve the direct modulation of cytochrome P-450 dependent monooxygenase function. This hypothesis was investigated by using purified rabbit cytochrome P-450IA2 and P-450IIB4 in a reconstitution system with purified NADPH:cytochrome P-450 oxidoreductase and L-alpha-dilauroylphosphatidylcholine. BHA caused a concentration-dependent decrease in cytochrome P-450IIB4 dependent 7-ethoxycoumarin O-deethylation, cyclohexane hydroxylation, and benzphetamine N-demethylation activities (IC50; 28, 75, and 290 microM, respectively) and in cytochrome P-450IA2 dependent 7-ethoxyresorufin O-deethylation and acetanilide para hydroxylation activities (IC50 approximately 225 microM). The inhibition of monooxygenation activity was accompanied by redox cycling due to the tert-butylquinone produced during BHA metabolism, as measured by increased NADPH and oxygen consumption or hydrogen peroxide and superoxide anion production. Glutathione was shown to reverse this redox cycling phenomenon but did not reverse the BHA-dependent inhibition of monooxygenation activity. Using standard steady-state kinetic analyses, BHA was shown to be a mixed-type competitive inhibitor of benzphetamine metabolism by cytochrome P-450IIB4, suggesting that BHA does not simply compete as an alternate substrate for the hemoprotein but must also bind to another catalytically functional form of cytochrome P-450. BHA was shown to bind as a ligand to both purified and microsomal cytochrome P-450IA2, resulting in a low to high (type I) spin-state perturbation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

The decline of fertility in Peninsular Malaysia.

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Age Factors↗

PubMedDate not supplied

Metabolism of azoxy derivatives of procarbazine by aldehyde dehydrogenase and xanthine oxidase.

Procarbazine, a 1,2-disubstituted hydrazine, is employed therapeutically in the treatment of Hodgkin's disease and a limited number of other neoplasias. The isomeric azoxy metabolites of procarbazine have recently been identified as the precursors of species responsible for both the anti-cancer efficacy and toxic effects mediated by this drug. This study demonstrates that cytosolic enzymes are involved in the metabolism of the azoxy metabolites of procarbazine. Two azoxy procarbazine oxidase activities were resolved by diethylaminoethyl (DEAE)-cellulose chromatography. The activity which did not bind to this column was purified to homogeneity and was identified as a phenobarbital-inducible form of cytosolic aldehyde dehydrogenase. This protein fraction was shown to metabolize only the azoxy 2 procarbazine isomer to yield N-isopropy-p-formylbenzamide (ALD) in a reaction which did not require NAD+ as cofactor. The ALD product formed was also a substrate for a subsequent NAD(+)-dependent reduction reaction catalyzed by that purified protein. The azoxy 2 procarbazine isomer and ALD were shown to be potent inhibitors of both the dehydrogenase and esterase activities of aldehyde dehydrogenase. The second azoxy procarbazine oxidase activity which was retained by the DEAE-cellulose column co-eluted with xanthine oxidase activity. Both the xanthine dehydrogenase/oxidase and azoxy procarbazine oxidase activities of this protein fraction were inhibited by allopurinol, a specific inhibitor of xanthine dehydrogenase. Xanthine dehydrogenase/oxidase was partially purified by an alternative procedure and was shown to metabolize both the azoxy 2 procarbazine isomer and ALD, ultimately producing N-isopropylterephthalamic acid. The ability of xanthine oxidase to metabolize azoxy 2 procarbazine and ALD was confirmed using commercial, purified milk xanthine oxidase.

Aldehyde Dehydrogenase↗

PubMedDate not supplied

Cardiac hypertrophy in experimental hypertension: interaction of the sodium ion, blood pressure and lisinopril.

The interaction of blood pressure, salt intake and the inhibition of angiotensin converting enzyme activity with cardiac hypertrophy were examined in the Dahl rat model. Eight-week-old salt sensitive and salt resistant rats were each separated into two colonies, one of which was maintained on a low salt and the other on a high salt diet for three weeks, at the end of which time both salt sensitive colonies were hypertensive. Each colony was then separated into two groups, one received no medication the other was given lisinopril until normotension was achieved. After 11 weeks of therapy, intra-arterial blood pressures and heart rates were recorded. The rats were sacrificed and heart weight to body weight ratios were determined. Both untreated salt sensitive groups displayed marked cardiac hypertrophy which correlated well with diastolic blood pressure irrespective of salt intake. Lisinopril therapy lowered blood pressures to normotensive levels in all groups except for salt sensitive rats ingesting a high salt diet where, despite a 10-fold increase in drug dose, normotension was not achieved. Significant cardiac regression accompanied lisinopril therapy in rats receiving low salt diets but high salt intake severely attenuated regression in both strains. There was no significant correlation between heart weight and blood pressure in the treated groups. The results suggest that cardiac regression appears to be mediated by other factors besides ventricular afterload pressure and that high salt intake adversely affects blood pressure and heart weight response to lisinopril therapy.

Angiotensin-Converting Enzyme Inhibitors↗