The effects of 5alpha-reduced androgens on maintenance and regeneration of prostate glands and seminal vesicles in castrated and hypophysectomized rats

The effects of 5alpha-androstane-3alpha, 17beta-diol (3alpha-diol) and 5alpha-androstane-3beta, 17beta-diol (3beta-diol) were studied in rats hypophysectomized and treated daily for 30 days with the steroids, starting on the day of surgery (hypophysectomized, H) or 30 days following the removal of pituitary (hypophysectomized regressed, HR). The ability of 3beta-diol to maintain and restimulate the prostate glands and seminal vesicles of castrated (C) and castrated regressed (CR) rats, respectively, was also studied. This androgen (3beta-diol) was able to maintain as well as rejuvenate to some degree the sexual accessory glands of all treatment groups. The prostate glands and seminal vesicles in both castrated experimental groups showed increased stimulation with progressively higher dosages of 3beta-diol. At all dose levels, stimulation of seminal vesicles of CR rats was comparable to that of non-regressed castrates. The prostate glands, on the other hand, showed better maintenance in the higher dosage group. In H rats, the stimulation of sexual accessory glands by both androgens was not significantly different than normal controls. The seminal vesicles and prostate glands of HR rats treated with 3alpha-diol were well stimulated and comparable to those of H rats treated with 3alpha-diol. The seminal vesicles of HR rats treated with 3beta-diol were also well stimulated, though not to the extent as those with 3alpha-diol treatment. The prostate glands of the 3beta-diol treated HR rats were significantly smaller than those of the 3alpha-diol treatment group. However, these miniature glands were morphologically stimulated as evidenced by mitosis of parenchymal cells and accumulation of secretory products in the alveoli. This study clearly indicates that 3beta-diol is biologically active and the degree of stimulation varies with the animal preparation in which the androgens were tested.

Severe cyanosis due to atrial septal defect and an anomalous inferior vena caval valve

Uncomplicated atrial septal defect is often associated with mild arterial desaturation. A case is reported with severe cyanosis and life-threatening hypoxemia due to an atrial septal defect. Cardiac catheterization revealed normal right heart pressures and an atrial septal defect with shunting of inferior vena caval blood into the left atrium. At surgery an anomalous inferior vena caval valve was found directing inferior vena caval blood into the left atrium. The embryologic basis for this association is discussed. The delayed onset of severe cyanosis may have been contributed to by the thoracic scoliosis.

The hepatic microsomal mixed-function oxidase system in man: cofactor effects and the influence of cholestasis

Microsomal preparations from 22 surgical specimens of normal, cholestatic or severely diseased human liver were analyzed with respect to the amounts of cytochromes P-450 and b5 and NADPH-cytochrome c reductase present. Normal human liver contained slightly less NADPH-cytochrome c reductase and cytochrome P-450 (mean 102.6 +/- 14.6 nmol/mg of protein per min. and 0.60 +/- 0.10 nmol/mg of protein, respectively) than is found in the adult rat, but wide variations were observed. Cytochrome b5 was present in comparable amounts to that in rat liver, and cytochrome b5/P --450 ratios were slightly increased in human liver as compared with rat liver. Cholestatic liver did not show significant alterations in the specific contents of any of these three components of the microsomal mixed-function oxidase system, but the two livers with severe parenchymal disease showed substantial reductions in all three. In vitro investigations of cofacter interrelationships in the N-demethylation of ethylmorphine by human liver microsomes suggested that NADPH was the favored electron donor, but NADH had a substantial (ca. 20%) synergistic effect (which was not enhanced by cyanide addition). These observations are in keeping with cytochrome b5 having a possible role in cytochrome P-450-mediated drug hydroxylation in man in both the normal state and after onset of cholestasis.

Patency of internal mammary-coronary grafts

Patency of internal mammary artery (IMA) coronary grafts was evaluated in 150 patients having an early (20 days) and late (13 months) postoperative angiogram. Early and late failure for 76 right IMA grafts was 3 and 5 respectively and for 139 left IMA grafts 7 and 7 an overall IMA patency of 95% and 90%. The IMA and coronary internal diameter did not relate to graft closure. Right IMA free flow did not correlate with graft closure. Free flow for thrombosed left IMA grafts (91 ml/min) was significantly (P less than 0.05) lower than for patent grafts (118 ml/min). Right IMA anastomotic flow of 55 ml/min was significantly (P less than 0.001) higher than occluded graft flow of 26 ml/min as was true for patent left IMA grafts (55 ml/min) and occluded grafts (43 ml/min) (P less than 0.025). Five of 215 IMA grafts had diffuse stenosis (greater than 50%). Saphenous vein coronary bypass was performed in 88 instances with an early patency of 89% (79/88) and a late patency of 88% (78/88). Only one of 38 vein grafts to the right coronary artery failed whereas eight of 44 grafts to the circumflex artery occluded. Experience was associated with increased late IMA patency from 81% (57/70), to 89% (;8/76), to 99% (68/69) in each successive group of 50 patients. Currently, the left IMA is routinely used for the left anterior descending artery and the right IMA is rarely used.

Drug-biomolecule interactions: drug toxicity and vitamin coenzyme depletion

Thirteen pyridine compounds, phenylbutazone, and three salicylates were studied for their effects upon the turnover of 7-14C-nicotinamide dinucleotides in the mouse. The compounds were administered at equitoxic doses (LD25) to 7-14C-nicotinic acid- (niacin) pretreated mice, and the induced excretion of urinary-14C was analyzed in terms of total 14C and percentage of total 14C as known metabolites of nicotinic acid. Of the 17 compounds, 12 afforded significant alterations in the total 14C excreted and five of these caused alterations in the disposition of the 7-14C-nicotinamide endogenously liberated from the 7-14C-nicotinamide adenine dinucleotide pool. Comparative depletions of 14C from brain, lungs, liver, and kidneys were studied with 10 of the pyridine compounds. Several tissues were found to be the sources of the urinary-14C, with the lungs being the most accessible source. Some compounds had effects at doses less than the LD25's, as shown by increased hexobarbital sleeping time in acute experiments with rats. These pyridine compounds were initially considered to act at the level of the nicotinamide dinucleotides in the normal biosynthetic pathway (nicotinic acid site) and/or at the level of glycohydrolase (nicotinamide site). In view of the inclusion of nicotinic acid, nicotinamide, salicylic acid, and phenylbutazone in this correlation between toxicity and 7-14C-nicotinamide mobilization, it is not necessary that the formation of compounds analogous to the nicotinamide dinucleotides plays a significant role in the toxic manifestations of the nicotinamide analogs. The displacement of 7-14C-nicotinamide dinucleotides from their corresponding apoenzymes with subsequent metabolism of the dinucleotides could explain the noted increased 7-14C-nicotinamide dinucleotide turnover and depletion which led to the toxic effects.

Soluble cytochrome P-450 from housefly microsomes. Partial purification and characterization of two hemoprotein forms

Housefly microsomes contain two spectrally different forms of cytochrome P-450 which we have termed P-450 and P-450I. Methods have been developed for the fractionation and chromatographic purification of these two hemoprotein forms. Microsomes are solubilized first with Triton X-100 in the presence of glycerol, dithiothreitol, ethylenediaminetetra-acetic acid, and phenobarbital. Cytochrome P-450 is recovered in a floating pellet after the addition of 25% ammonium sulfate followed by centrifugation, whereas cytochrome P-450I remains in the 25% ammonium sulfate supernatant fluid. Cytochrome P-450 is purified further by Sephadez G-200 and DEAE-Sephadex A-50 column chromatography, which also allows the isolation of cytochrome b5 and NADPH-dependent cytochrome P-450 reductase in good yields and with little cross-contamination. Cytochrome P-450 apparently is free of cytochromes b5 and P-420 as well as of reductase and is obtained in a final yield of approximately 16% with a 6.9-fold purification. Its maximum absorbance is at 45 mn in the CO-difference spectrum and its average extinction coefficient is 103 cm-1 nm-1. Cytochrome P-450I is purified by Sephadex G-25 column chromatography but still contains some cytochromes b5 and P-420 as well as reductase. Its maximum absorbance is at 448.5 nm in the CO-difference spectrum and its extinction coefficient is 83 to 86 cm-1 mM-1. Both cytochromes hydroxylate type I substrates such as aminopyrine. Sufficient amounts of reductase are present in the cytochrome P-450I preparation to sustain activity, but the reductase has to be added to cytochrome P-450 in a reconstituted system for activity. Cytochrome P-450 is fairly stable, whereas cytochrome P-450I can be isolated only when protected by a substrate (phenobarbital). Detergent-solubilized housefly cytochromes P-450 and P-450I seem to correspond to either aggregates or oligomeric proteins. Cytochrome P-450 appears to correspond to a tetramer, each subunit having a molecular weight of 45,000, whereas cytochrome P-450I may correspond to an aggregate of at least 10 subunits. The cytochrome P-450 aggregate is dissociated by 6 M urea, but cytochrome P-450I remains as such.

Bacterial metabolism of 3-hydroxy-3-methylglutaric acid

An organism belonging to Pseudomonadaceae and capable of utilizing 3-hydroxy-3-methylglutarate as sole carbon source has been isolated from soil. Whole-cell preparations catalyze the oxidation of acetoacetate, acetate, glyoxylate, and citric acid cycle intermediates. Cell-free extracts of 3-hydroxy-3-methylglutarate-grown cells show an adenosine triphosphate, coenzyme A (CoA), and Mg(2+)-dependent conversion of 3-hydroxy-3-methylglutarate to 3-hydroxy-3-methylglutaryl-CoA. Succinyl-CoA-generating system has no effect on the activation and catabolism of 3-hydroxy-3-methylglutarate.

The biosynthesis of some androst-16-enes from C21 and C19 steroids in boar testicular and adrenal tissue

1. The formation of androst-16-enes from [4-(14)C]progesterone has been investigated with long-term incubations and short-term kinetic studies. After 4hr., 1.7 and 10.3% respectively of 3alpha- and 3beta-hydroxy-5alpha-androst-16-enes were formed in boar testis minces, but much smaller yields were obtained in boar adrenal. Both tissues formed small quantities of androsta-4,16-dien-3-one. 2. The amounts of androst-4-ene-3,17-dione and testosterone isolated were small, suggesting that androst-16-ene formation may occur preferentially in the boar testis. 3. In the absence of tissue no radioactive androst-16-enes were formed. 4. Incubation of both [4-(14)C]pregnenolone and [7alpha-(3)H]progesterone resulted in 3alpha- and 3beta-hydroxy-5alpha-androst-16-enes containing (3)H/(14)C ratios of near unity and confirmed that both C(21) steroids were precursors. A similar incubation with 17alpha-hydroxy[4-(14)C]-progesterone and [7alpha-(3)H]progesterone gave the same Delta(16)-alcohols, but they contained only (3)H, indicating that side-chain cleavage of pregnenolone and progesterone occurred before 17alpha-hydroxylation. 5. Dehydroepiandrosterone, testosterone, testosterone acetate and 16-dehydroprogesterone were not found to be precursors of Delta(16)-steroids. 6. A pathway is proposed for the biosynthesis of 3alpha- and 3beta-hydroxy-5alpha-androst-16-enes from pregnenolone and progesterone; this may involve androsta-4,16-dien-3-one as an intermediate, but excludes 17alpha-hydroxyprogesterone, testosterone and dehydroepiandrosterone.

Studies on the biosynthesis of 16-dehydro steroids. The metabolism of [4-14C]pregnenolone by boar adrenal and testis tissue in vitro

1. The metabolism of [4-(14)C]pregnenolone in vitro by boar adrenocortical and testis tissue has been studied. 2. Boar testis tissue formed three labelled Delta(16)-steroids, 5alpha-androst-16-en-3alpha-ol, 5alpha-androst-16-en-3beta-ol and androsta-4,16-dien-3-one. In adrenal tissue very much smaller yields of the same metabolites were obtained. 3. Both tissues produced labelled progesterone, androst-4-ene-3,17-dione and testosterone in varying quantities. The amount of progesterone was about 120 times greater in the adrenal tissue. In testis tissue dehydroepiandrosterone was found only in small quantity. 4. A pathway is suggested for the biosynthesis of Delta(16)-steroids from pregnenolone in boar testis tissue. The possibility that progesterone may be an intermediate is discussed.