Certain steroids having an oxo group at the C-17 or C-20 position such as pregnenolone and dehydroisoandrosterone inhibit the cholesterol transport from lysosomes to other cellular sites. Taking advantage of the fact that the inhibition is reversed upon removal of the steroids, we studied the factors that control the cholesterol transport from lysosomes to other cellular sites in macrophages. M...

Oxidant-mediated modulation of the intracellular redox state affects the apoptotic cascade by altering the balance between cellular signals for survival and suicide. Apolipoprotein A-IV (Apo A-IV) is known to possess antioxidant-like activity. In the present study, we tested 1) whether Apo A-IV could influence redox-dependent apoptosis and, if so, 2) whether such an effect could be mediated by ...

N-Hydroxy-2-acetylaminofluorene (N-OH-2-AAF) sulfotransferase is an enzyme that catalyzes the sulfate transfer from the active sulfate, 3'-phosphoadenosine 5'-phosphosulfate (PAPS), to N-OH-2-AAF to form a highly reactive product acetylaminofluorene N-sulfate. It has been purified about 2000-fold with a yield of over 12% from adult Sprague-Dawley male rat livers by an eight-step procedure. The ...

Oxidative stress has been implicated in the pathophysiology of myocardial failure. We tested the hypothesis that oxidative stress can regulate extracellular matrix in cardiac fibroblasts. Neonatal and adult rat cardiac fibroblasts in vitro were exposed to H(2)O(2) (0.05-5 microM) or the superoxide-generating system xanthine (500 microM) plus xanthine oxidase (0.001-0.1 mU/ml) (XXO) for 24 h. In...

The use of steroid hormones containing tagged atoms promises to have an important part in the study of their metabolism. The relative availability of radioactive Cl4 manufactured in the uranium chain-reacting pile at Oak Ridge has facilitated the synthesis of such compounds containing labeled carbon atoms (1). Through the cooperation of Dr. Konrad Dobriner of the Sloan-Kettering Institute for C...

It has long been recognized that many of the steroids, including the androgens, are excreted in urine in conjugation with other substances which render them not only more water-soluble but also neutralize their physiological activity to a great extent. In 1936 Cohen and Marrian (1) isolated estriol glucuronide, the conjugated form of estriol, from the urine of pregnant women and in 1936 Venning...

Following primary infection with Herpes Simplex Virus (HSV), the virus persists in episomal form in the local sensory ganglia. Periodic reactivation by various stimuli results in a recrudescent lesion at or near the initial site of infection due to retrograde axonal transport [l]. As yet there is no suitable vaccine for its prevention within the human population p]. We investigated the potentia...

It has been considered for some time that steroid hormones may exert their regulatory effects by influencing certain enzymes.' However, our present knowledge of the mechanisms of steroid action upon enzymes is limited. Estrogens have been shown to stimulate the transfer of hydrogen between diand triphosphopyridine nucleotides,2 ' although there is disagreement as to the role of steroids in this...