Internalization, recycling, and redistribution of vasopressin receptors in rat hepatocytes.

Three hours after isolation, cultured hepatocytes have approximately 150,000 surface vasopressin receptors/cell, and these exhibit a Kd for 125I-vasopressin of 6 nM based on calculation of Koff/Kon, or a Kd of 9.5 nM based on Scatchard plot analysis. After the binding of 125I-vasopressin to its receptor on the hepatocyte surface, this complex is internalized with a t1/2 of 3-6 min.

Determination of 16 alpha-hydroxyestrone by radioimmunoassay in systemic lupus erythematosus.

A radioimmunoassay for the feminizing metabolite 16 alpha-hydroxyestrone was applied to a variety of sera from healthy volunteers, patients with active or inactive systemic lupus erythematosus (SLE), and patients with other rheumatic diseases. A significant increase in this metabolite was detected in patients with SLE, especially those with active disease, compared with normal controls (P less than 0.001).

Coated vesicles contain a phosphatidylinositol kinase.

When coated vesicles (CVs) are incubated with [gamma-32P]ATP, radioactivity is rapidly incorporated into a compound identified by thin layer chromatography as phosphatidylinositol 4-phosphate. This activity has been identified in CVs isolated from bovine brain as well as from rat liver and chick embryo skeletal muscle. Phosphatidylinositol (PI) kinase is not separated from CVs during agarose electrophoresis, which produces CVs of greater than 95% purity, indicating that the activity present does not derive from contamination.

Estradiol 16 alpha-hydroxylation in the mouse correlates with mammary tumor incidence and presence of murine mammary tumor virus: a possible model for the hormonal etiology of breast cancer in humans.

In this report, we describe our findings on the relationship between estradiol 16 alpha-hydroxylation and mammary tumor incidence. A close correlation between the two has been demonstrated with 16-hydroxylation being elevated in strains with a high incidence of tumors, such as RIII and C3H, and low in strains with a low incidence of cancer, such as C57BL. The extent of reaction is highly reproducible and unaffected by age or presence of overt mammary tumors.

The formation at 37 C of a nondissociable receptor-estradiol complex.

The receptor-estradiol complex formed in rat uterine cytosol when heated at 37 C converts from a dissociable to a nondissociable form. The conversion is best observed in cytosols pretreated with charcoal at 0 C which renders the subsequently formed receptor-estradiol complexes thermostable at 37 C. In the presence of dithiothreitol the heated complex remains dissociable.

Castration affects male rat brain opiate receptor content.

We previously reported that saturable stereospecific binding of [3H]-naltrexone in rat brain homogenates prepared from castrated male rats was greater than the corresponding binding in intact animals. We now report that we have replicated these results and that the difficulty of other investigators in observing these differences is due to methodological factors. Specifically, when samples were filtered individually and rapidly, differences between castrated and intact rats were maintained.

Experimental intracranial septic infarction: magnetic resonance enhancement.

Intracranial brain abscess was produced in three monkeys by embolization of a small pledget of polyvinyl alcohol (PVA) soaked in a broth of Staphylococcus aureus. Imaging of the chronic stable abscess was performed on the General Electric 8800 CT unit (Milwaukee, Wis.) and a 1.

Stereochemistry of 1,2-hydrogen loss during aromatization in the brain.

The stereochemistry of hydrogen loss from C-1 and C-2 during aromatization in rat brain was studied using androstenedione containing a known distribution of isotopic label. Comparison of the tritium content of the estrone obtained from the aromatization of androstenedione labeled predominantly in the 1 alpha,2 alpha positions with that in estrone obtained from a parallel incubation using substrate with label in the 1 beta,2 beta orientation gave an estrone alpha/beta ratio of 3.6.

Increased levels of 16 alpha-hydroxyestrone-modified proteins in pregnancy and in systemic lupus erythematosus.

The ketolic estrogen 16 alpha-hydroxyestrone (16 alpha OHE) reacts with lysine residues, forming stable covalent adducts with proteins. To determine the extent of protein modification by 16 alpha OHE in vivo, we measured the level of 16 alpha OHE-lysine present within proteins of varying half-lives obtained from normal subjects, patients with systemic lupus erythematosus (SLE), and pregnant women. The latter groups have higher than normal levels of plasma 16 alpha OHE.

Nonpharmacological control of hypertension.

Ability to safely withdraw well-controlled mild hypertensives from drugs is being tested in a three-group randomized trial. Group I (intervention) was removed from drugs after the first 2 months of nutrition counseling. Counseling is continuing through the remaining years of the trial to achieve a minimum weight loss of 10 lb if overweight, reduction of sodium intake to less than 1,800 mg, and reduction of alcohol intake to not more than two drinks per day.

19-Hydroxylation of androgens in the rat brain.

Aromatization of androgens in the central nervous system is linked with sexual differentiation of the brain and, thus, determines the nature of sexual behavior and the control of gonadotropin secretion. The process of aromatization, as determined in the human placenta, proceeds through two successive hydroxylations at C-19, the products of which are then virtually completely converted via a third hydroxylation at C-2 to estrogens. We now report that in the rat brain, 19-hydroxylation of androgens greatly exceeds aromatization and the 19-hydroxy- and 19-oxoandrogen products accumulate in quantities 5 times greater than the estrogens.

Hyperbaric oxygenation in peripheral ischaemic lesions in infants.

Acute peripheral arterial occlusion may lead to gangrene, with loss of parts of arms and legs. Three infants with disseminated intravascular clotting developed dark red discoloration of the tips of fingers and toes which progressed proximally. Repeated hyperbaric oxygenation treatments caused regression of the demarcation line and further progression of necrosis stopped.

Effects of the aminonucleoside of puromycin on glomerular epithelial cells in vitro.

Glomerular epithelial cells (GECs) in vitro provide a useful model for the study of the mechanism(s) underlying the nephrotic syndrome of rats induced by the aminonucleoside of puromycin (PAN). Some of the toxicities of PAN are nonspecific, in that the constituent molecules of PAN (adenosine and puromycin) cause similar effects in vitro. These include GEC blebbing and rounding, reduced uptake of precursors of protein (leucine) and glycoprotein (glucosamine) synthesis, and increased permeability of the GEC membrane to adenosine.

Radiometric analysis of oxidative reactions in aromatization by placental microsomes. Presence of differential isotope effects.

In order to study the initial as well as the final steps in the aromatization of androgens to estrogens, high-specific activity [19-C3H3]androstenedione and testosterone were synthesized. Incubations of [19-C3H3]androstenedione with human placental microsomes resulted in the generation of [3H]water, as a result of the dual hydroxylation at C-19, and [3H]formic acid reflecting final aromatization. After an initial lag in the production of [3H]formic acid, the two radiolabeled products were formed linearly with time at a ratio of 2 to 1 under subsaturating conditions and 2.

Trial on control of hypertension by nutritional means: three-year results.

Ability to safely withdraw medication from well-controlled mild hypertensives was tested in a 3-group randomized trial. Group I (Intervention): drugs were stopped 2 months after nutrition counseling began. Counselling continued throughout the remaining years of the trial to achieve: a minimum of 10 lb weight loss if overweight; reduction of sodium intake to 1800 mg/day or less; reduction of alcohol intake to not more than 2 drinks per day.

Catechol estrogen formation and metabolism in brain tissue: comparison of tritium release from different positions in ring A of the steroid.

Catechol estrogens labeled with 3H at different positions in rings A and B of the steroid were synthesized by chemical or enzymatic methods, and their oxidative transformation by male rat brain microsomes was followed by the transfer of 3H into 3H2O. This reaction was shown to occur more readily with the catechol estrogens than with the parent steroid and was also influenced by the position of the radiolabel. Tritium was displaced less readily from C-1 than from C-2 or C-4 of the aromatic ring.

Regiospecific transfer of tritium into 3H2O from labeled estrogens by mushroom tyrosinase.

The specificity of mushroom tyrosinase in displacing 3H from estradiol and catechol estrogens labeled at C-1, C-2, C-4 or C-6,7 was investigated under various conditions. [2-3H]E2 Yielded significant amounts of 3H2O, in the presence of NADH, and the rate of 3H loss from the steroid paralleled that of the radioactivity remaining in the aqueous fraction after extraction with organic solvents. NADH had little effect on the release of 3H from [1-3H]E2 or [4-3H]E2 but glutathione was highly active in this respect, with considerable differences being observed between lyophilizable 3H2O and yields of water-soluble products.

Effects of 2-hydroxyestradiol-17 beta, 2-hydroxyestradiol-17 alpha, and 4-hydroxyestrone on the preovulatory luteinizing hormone surge in the rat: agonist and antagonist actions.

Four-day cycling rats equipped with intracardiac catheters were injected with 2-hydroxyestradiol-17 beta (2OHE2-17 beta) at 0800, 0900, 1000, and 1200 h on the morning of proestrus. The administration at 0800 and 0900 h resulted in abolition of the afternoon preovulatory LH surge in virtually all animals. Injections given at 1000 and 1200 h were ineffective in this respect.

Suppression of the preovulatory luteinizing hormone surge in the rat by 2-hydroxyestrone: relationship to endogenous estradiol levels.

Injection of 100 micrograms 2-hydroxyestrone (2OHE1) at various times on the morning of proestrus into normal 4-day-cycling rats results in abolition of the preovulatory LH surge in a number of animals tested. The greatest response was observed when the administration of 2OHE1 coincided with endogenous estradiol (E2) levels that were close to but not at their maximal proestrous levels. The catechol estrogen failed to abolish the LH surge if given much earlier or after the E2 maximum had already been reached.

Colonic obstruction and perforation due to Trichuris trichiura.

Acute obstruction of the cecum due to Trichuris trichiura developed in a 25-year-old Puerto Rican man who had emigrated to the northeastern United States five years previously. Obstruction was caused by a large tangled mass of whipworms . Perforation of the ascending colon also occurred and resulted in pericolic abscess.

The influence of dietary protein and carbohydrate on the principal oxidative biotransformations of estradiol in normal subjects.

Dietary protein, when substituted for carbohydrate or fat, can increase cytochrome P-450-dependent drug oxidation rates in humans. Endogenous estrogens, as well as drugs, are also metabolized by cytochrome P-450 and other enzymes in the hepatic endoplasmic reticulum. Therefore, it was of interest to determine whether variations in diet can alter the major metabolic pathways for estrogens, as assessed by radiometric methods.

The reaction of 16 alpha-hydroxyestrone with erythrocytes in vitro and in vivo.

16 alpha-Hydroxyestrone (16 alpha OHE ) has been shown previously to react with albumin, forming stable covalent adducts with lysine residues. The incubation of [3H]16 alpha OHE with whole blood also results in the incorporation of tritium into cells, with the rate of incorporation paralleling that of 16 alpha OHE -protein adduct formation. 32% of erythrocyte acid-precipitable radioactivity was found to be present within membrane proteins and electrophoresis demonstrated that several of these proteins are modified by [3H]16 alpha OHE .