Activation of muscarinic receptors inhibits neurogenic nitric oxide in the corpus cavernosum.

The functional role of cholinergic transmission in erection is still far from being fully elucidated. This work aims to further elucidate the modulatory role of neostigmine on NO in the corpus cavernosum and to highlight whether cholinergic transmission in the penis modulates sildenafil action. The isolated rabbit corpus cavernosum and measurement of intracavernosal pressure in the anesthetized rat model were used. Neostigmine (0.02 mg/kg) reduced increase of intracavernosal pressure/mean arterial pressure (ICP/MAP) next to cavernous nerve stimulation. Higher doses (0.06 and 0.4 mg/kg) potentiated ICP/MAP rise and atropine (1.5 and 10 mg/kg) did the opposite. In vitro, neostigmine (10⁻5 and 10⁻4 M) potentiated neurogenic relaxations and this effect was significantly inhibited by hexamethonium (10⁻4 M) or N(ω)-propyl-L-arginine (3 × 10⁻5 M) and partially but significantly reduced in the presence of atropine. Lower dose neostigmine (10⁻7 M), inhibited electrically induced relaxation over the range of 1-4 Hz, atropine (10⁻6 M) almost abolished this inhibitory effect as well as N(G)-nitro-L-arginine (10⁻5 M). It was also significantly reduced by selective nNOS inhibitor N(ω)-propyl-L-arginine (3 × 10⁻5 M). Nicotine (10⁻4 M) significantly potentiated electrically induced relaxations amounting to 84.625 ± 8.06% at 1 Hz and potentiated the effect of sildenafil synergistically. Hexamthonium did the opposite. The potentiatory effect of sildenafil on neurogenic erection was significantly reduced by low dose neostigmine both in vitro and in vivo. This study provides evidence that muscarinic receptors may modulate NO synthesis in nitrergic nerves by inhibiting nNOS and high level of cholinergic stimulation may activate nicotinic receptors to promote erection probably by potentiating NO synthesis in nitrergic nerves.

Involvement of alpha-receptors and potassium channels in the mechanism of action of sildenafil citrate.

Modulation of the adrenergic activity and interfering with channels such as potassium channels may affect relaxation and contraction of the corpus cavernosum. Sildenafil is a selective phosphodiesterase-5 inhibitor, proven effective in treating erectile dysfunction. In this study, the effect of sildenafil citrate on alpha-receptors modulation and potassium channels was tested. The direct relaxant effect of sildenafil citrate was studied by measuring changes in isometric tension in isolated strips of rabbit corpus cavernosum and rat aortic ring precontracted with phenylephrine or KCl compared to that of diazoxide in the presence and absence of tetraethylammonium. The inhibitory effect of sildenafil on electrical field stimulation-induced contraction of rabbit corpus cavernosum and rat anococcygeus muscle was also studied compared to that of phentolamine. Muscle relaxant effect of sildenafil (1 x 10(-9)-1 x 10(-6) M on phenylephrine-precontracted rabbit corpus cavernosum strips was not attenuated by N(G)-nitro-L-arginine (3 x 10(-5) M). Cumulative addition of sildenafil (1 x 10(-9)-1 x 10(-6) M) and phentolamine (1 x 10(-9)-1 x 10(-6) M) to the organ bath dose-dependently inhibited electrical field stimulation-induced contraction of rabbit corpus cavernosum and rat anococcygeus muscle, with almost similar EC(50) values. Sildenafil (1 x 10(-7) M) also inhibited phenylephrine-induced contraction of rat aortic rings by 39.83+/-3.01%. In addition, tetraethylammonium (1 x 10(-3) M) significantly attenuated the muscle relaxant effect of sildenafil (1 x 10(-9)-1 x 10(-6) M) on phenylephrine-precontracted strips of rabbit corpus cavernosum. Sildenafil citrate is capable of producing cavernosal smooth muscle relaxation by an additional mechanism that may involve alpha-receptors and potassium channel opening.

Effect of sildenafil on the isolated rat aortic rings.

Sildenafil, a highly selective inhibitor of PDE 5, is effective in the treatment of erectile dysfunction. Penile erection involves relaxation of smooth muscle of corpus cavernosum and its associated arterioles. The objective of this study was to investigate the effect of sildenafil on nitric oxide/cyclic guanosine monophosphate (NO/cGMP)-dependent relaxation of rat aortic rings. The contribution of sildenafil to the vasorelaxation of rat aortic rings was also investigated. Sildenafil produced significant potentiation of acetylcholine (ACh, 2 x 10(-6) m)-induced relaxation at concentration > or =1 x 10(-8) m. Addition of sildenafil (1 x 10(-7) m) to aortic rings failed to alter the effect of N(G)-nitro-L-arginine (l-NNA, 3 x 10(-5) m) or methylene blue (MB, 3 x 10(-5) m) on ACh response. Similarly, sildenafil (1 x 10(-7) m) augmented significantly the vasorelaxation induced by sodium nitroprusside over the range of 1 x 10(-9)-1 x 10(-8) m. When added to phenylephrine (3 x 10(-6) m)-precontracted rat aortic rings, sildenafil (1 x 10(-9)-1 x 10(-4) m) induced concentration-dependent relaxation reaching a maximum of 96.48 +/- 1.44%. These relaxations were not significantly attenuated by previous incubation with L-NNA (3 x 10(-5) m) or MB (3 x 10(-5) m). Denudation did not significantly affect the vasorelaxant effect of sildenafil. Sildenafil may act in the rat aortic rings through the amplification of NO/cGMP pathway. It may augment both basal endothelial NO function and exogenous NO-dependent vasodilatation. However, sildenafil may act by a mechanism independent of NO/cGMP pathway and this mechanism contributes to its smooth muscle relaxant effect.

Comparative effects of sildenafil, phentolamine, yohimbine and L-arginine on the rabbit corpus cavernosum.

Penile erection involves relaxation of smooth muscle of corpus cavernosum and associated arterioles. Sildenafil, a highly selective inhibitor of phosphodiesterase type 5, is effective in the treatment of erectile dysfunction. The aim of this study is to investigate the effect of sildenafil on smooth muscle of the rabbit corpus cavernosum (RCC) and to compare its effect with those of phentolamine, yohimbine and L-arginine. The effects of sildenafil, phentolamine, yohimbine and L-arginine were studied on the response of the RCC to electrical field stimulation (EFS) as well as on the phenylephrine (PE, 3 x 10(-6) M)-induced tone. EFS caused transient, frequency-dependent relaxation of the RCC that was inhibited by the nitric oxide synthase inhibitor NG-nitro-L-arginine (3 x 10(-5) M). Sildenafil (1 x 10(-9)-1 x 10(-6) M) and phentolamine (1 x 10(-9)-1 x 10(-6) M) enhanced the EFS-induced relaxation in a concentration-dependent manner with ED50 of 0.056 +/- 0.004 and 0.572 +/-0.035 microM at 8 Hz, respectively, yohimbine (3 x 10(-7)-3 x 10(-5) M) and L-arginine (3 x 10(-6)-3 x 10(-4) M) did not show significant effects (ED50 at 8 Hz = 35.84 +/-2.24 and 2.164 +/- 0.174 microM, respectively). Sildenafil (1 x 10(-9) and 1 x 10(-8) M) potentiated the EFS-induced relaxation caused by L-arginine (3 x 10(-5) m). Sildenafil, phentolamine, yohimbine and L-arginine reduced the PE-induced tone to different extents; the ED50 values were 0.81 +/- 0.097, 0.49 +/- 0.025 and 13.97 +/- 1.10 microM, respectively. Maximum concentration of L-arginine used failed to produce 50% relaxation (ED20 = 221.82 +/- 15.71 microM). The muscle relaxant effects of different combinations of sildenafil and L-arginine on PE-induced tone did not differ significantly from the sum of the individual effects. The results demonstrate that sildenafil, when compared to other drugs used in penile erection dysfunction, shows the highest potency on the nitrergic transmission in the RCC. On the other hand, phentolamine was found to possess the highest potency in inducing relaxation of RCC proving that its action is independent on the stimulated neurogenic system. In addition, the combination of less effective doses of sildenafil and L-arginine has a potential advantage on erectile functions. The importance of this combination remains to be solved clinically.

Role of nitric oxide in catalepsy and hyperthermia in morphine-dependent rats.

The possible involvement of nitric oxide (NO) in morphine-induced catalepsy and hyperthermia was studied in morphine-dependent rats. Four days repeated injection regimen was used to induce morphine dependence, which was assessed by naloxone challenge (0.5 mg x kg(-1), s.c.). Pretreatment of rats with the NO synthase inhibitor, N(G)-nitro-L-arginine (L-NA, 8 mg x kg(-1) twice daily, i.p.) potentiated the cataleptic response of morphine as shown by a rightward shift in the morphine-log dose-response curve. Prior treatment of rats with the NO precursor, L-arginine (200 mg x kg(-1), twice daily, i.p.) abolished the potent effect of L-NA and restored the cataleptic scores to levels similar to those of morphine-dependent rats. The same dose of L-NA significantly blocked morphine-induced hyperthermia at the dose levels of morphine (15-105 mg x kg(-1)) and this effect was reversed by L-arginine. These data provide the first experimental evidence that NO is involved in morphine induced catalepsy and hyperthermia and demonstrated that blockade of NO synthesis may suggest a dangerous interaction with opioids in the control of motor function.

Short-term aortic barodenervation diminishes alpha 1-adrenoceptor reactivity in rat aortic smooth muscle.

Our previous studies have shown that aortic baroreceptor denervation elicits acute increases in blood pressure and significant elevations of sympathetic activity and peripheral vascular resistance. This study investigated the short-term (3 and 48 h) effect of aortic barodenervation and associated sympathetic hyperactivity on the functional activity of alpha 1-adrenoceptors in rat aortic smooth muscle. Compared with sham operation, aortic barodenervation caused acute rises in blood pressure and heart rate and reductions in baroreflex sensitivity. Blood pressure and heart rate remained elevated when measured in conscious aortic barodenervated rats 3 h after surgery but subsided to sham-operated levels at 48 h; the baroreflex sensitivity, however, remained attenuated. Hexamethonium (0.5-4 mg/kg, i.v.) elicited significantly (P < 0.05) greater depressor responses in conscious aortic barodenervated rats than in sham-operated rats at both 3 and 48 h, suggesting a higher sympathetic activity in denervated rats. Exposure of aortic rings from aortic barodenervated and sham-operated rats to cumulative addition of phenylephrine (alpha 1-adrenoceptor agonist, 3 x 10(-8)-1 x 10(-4) M) resulted in concentration related contractile responses that were similar in the two groups of rats at 3 h in contrast to significantly (P < 0.05) smaller contractions in rings from denervated rats at 48 h. The maximum contraction developed (Emax) at 48 h showed approximately 50% reduction in rings from aortic barodenervated compared with sham-operated rats (239 +/- 16 vs. 558 +/- 15 mg tension/mg tissue). The pA2 value for prazosin (alpha 1-adrenoceptor antagonist) was not altered by aortic barodenervation at 3 h but showed significant (P < 0.05) increases, compared with sham-operated values, at 48 h. It is concluded that short-term aortic barodenervation results in an elevation of sympathetic activity that coincides with reduced responsiveness of aortic smooth muscle to alpha 1-adrenoceptor activation. The aortic barodenervation-induced alpha 1-adrenoceptor desensitization is not a result of decreased receptor affinity but may involve an alteration of receptor density or in the post-receptor activation events.

Enhanced endothelial nitric oxide activity contributes to the reduced responsiveness of vascular alpha1-adrenoceptors following aortic barodenervation.

We have recently shown that short-term aortic barodenervation diminishes constrictor responses to activation of alpha1-adrenoceptors in rat aortic smooth muscle. This study investigated the potential role of vascular endothelium and its derived vasoactive substances, nitric oxide and prostaglandins, in the reduced alpha1-adrenoceptor responsiveness after aortic barodenervation. Exposure of isolated aortic rings from aortic barodenervated and sham-operated rats 48 h after surgery to cumulative addition of phenylephrine (alpha1-adrenoceptor agonist, 3 x 10(-8) - 1 X 10(-4) M) resulted in concentration-related contractions that were significantly (P < 0.05) smaller in rings of denervated rats. Removal of the endothelium increased phenylephrine-mediated contractions in rings obtained from aortic barodenervated rats to near sham-operated levels as demonstrated by the similar contractile responses and slopes of the regression lines of the concentration-response curves. Pretreatment with indomethacin (cyclooxygenase inhibitor, 1 x 10[-5] M) had no effect on contractile responses to phenylephrine in rings from both groups of rats. In contrast, N(G)-nitro-L-arginine (nitric oxide synthase inhibitor, 3 x 10[-5] M) elevated basal vascular tone and significantly (P < 0.05) increased alpha1-adrenoceptor responsiveness, effects that were more evident in rings from denervated compared with sham-operated rats. N(G)-nitro-L-arginine produced significantly (P < 0.05) greater increases in the slopes of the regression lines (136.1 +/- 22% vs. 73.0 +/- 8.6% mg tension/mg tissue/log molar concentration) and maximum contractile response (Emax) to phenylephrine (161.2 +/- 8.2% vs. 76.7 +/- 6.1%) in rings from denervated compared with sham-operated rats suggesting an enhanced nitric oxide activity in aortas of denervated rats. This notion is further supported by the finding that cumulative i.v. administration of N(G)-nitro-L-arginine (1, 2, 4 and 8 mg/kg) elicited significantly (P < 0.05) greater pressor responses in conscious barodenervated compared with sham-operated rats. These results suggest that the endothelium plays a major role in the reduced constrictor responses to alpha1-adrenoceptor activation that occurs shortly after aortic barodenervation. This effect of the endothelium appears to involve, at least in part, enhancement of endothelial nitric oxide activity.

Aspartate-induced neuronal necrosis in infant mice: protective effect of carbohydrate and insulin.

Infant mice given large doses of glutamate or aspartate develop hypothalamic neuronal necrosis. Studies by others demonstrated that simultaneous administration of carbohydrate or prior injection with insulin markedly decreased glutamate-induced neuronal damage. We investigated whether carbohydrate and insulin exert a similar protective effect against aspartate-induced neuronal necrosis. Eight-day-old mice administered aspartate at 750 and 1000 mg/kg body weight developed neuronal necrosis (45.9 +/- 7.2 and 80.8 +/- 17.3 necrotic neurons/section, respectively). When carbohydrate (1 g/kg body weight) was administered simultaneously no lesions were detected in mice administered 750 mg/kg body weight aspartate, while 30.1 +/- 14.2 necrotic neurons/section were noted at 1000 mg aspartate/kg body weight. Mice administered 1000 mg/kg body weight aspartate with prior injection of insulin had 28.4 +/- 12.6 necrotic neurons/section, while 4.2 +/- 1.4 necrotic neurons/section were noted in insulin treated mice given 750 mg aspartate/kg body weight. Carbohydrate and insulin treatments has only minimal effects on plasma aspartate concentrations.

Effect of insulin and oral glutathione on glutathione levels and superoxide dismutase activities in organs of rats with streptozocin-induced diabetes.

The effect of insulin or glutathione treatment on glutathione content of liver and jejunal mucosa and on superoxide dismutase (SOD) activity of liver, kidney, and erythrocytes was investigated in pair-fed animals with streptozocin (STZ)-induced diabetes. Diabetes lowered hepatic glutathione concentration, but glutathione concentration of the jejunal mucosa was not affected. Insulin, but not oral glutathione, restored hepatic glutathione concentration to normal levels. Diabetes depressed activity of the cytosolic form of SOD in liver, kidney, and erythrocyte. Treatment of diabetic rats with oral glutathione or intramuscular insulin increased cytosolic SOD activity of renal cortex and liver (but not erythrocytes) to control levels. These results suggest a link between glutathione metabolism and cytosolic SOD activity in diabetes.

Correlation of glutamate plus aspartate dose, plasma amino acid concentration and neuronal necrosis in infant mice.

Eight-day-old mice were given by gavage glutamate and aspartate mixtures providing each amino acid at 125, 250 or 500 mg/kg body weight (250, 500 and 1000 mg total dicarboxylic amino acids/kg) and the degree and extent of neuronal necrosis were determined. Similar studies were carried out in mice given monosodium L-glutamate at 250 or 500 mg/kg body weight. Plasma aspartate and glutamate concentrations were determined at each dose level. No animal given either glutamate or the glutamate plus aspartate mixture at 250 mg/kg developed neuronal necrosis. However, neuronal necrosis developed in 30% of animals given glutamate at 500 mg/kg (12+/-2 necrotic neurons/section in the region of maximal damage) and in 17% of animals given 250 mg glutamate/kg plus 250 mg aspartate/kg (11-13 necrotic neurons/section in the region of maximal damage). The threshold mean peak plasma glutamate plus aspartate concentration associated with neuronal necrosis was 128+/-24 mumol/dl. Using these data, and previously published data for aspartate-induced neurotoxicity (Finkelstein et al. Toxicology 1983, 29, 109), the individual threshold plasma glutamate and aspartate concentrations associated with neuronal necrosis were calculated to be 110 mumol/dl for aspartate and 75 mumol/dl for glutamate.

Effect of carbohydrate ingestion on plasma aspartate concentrations in infant mice administered sodium L-aspartate.

Previous studies of infant pigs have demonstrated that simultaneous ingestion of carbohydrate (1 g/kg body weight) and glutamate (300 mg/kg body weight) resulted in markedly lower mean peak plasma glutamate concentration and a smaller area under the plasma glutamate concentration-time curve (AUC) than ingestion of the equivalent amount of glutamate alone. This study was carried out to investigate whether a similar carbohydrate-induced effect occurred with the other dicarboxylic amino acid, aspartate. Eight-day-old mice were administered sodium L-aspartate at 250, 500 and 1000 mg/kg body weight with and without 1.0 g/kg body weight of partially hydrolyzed cornstarch. Mean peak plasma aspartate concentration and plasma aspartate AUC values increased in proportion to the aspartate dose. The addition of carbohydrate to the aspartate solution had no significant effect on either mean peak plasma aspartate concentrations or AUC values at aspartate doses of 250 and 500 mg/kg body weight. A modest, but significant effect of carbohydrate was noted on the mean peak plasma aspartate levels in animals administered 1000 mg/kg body weight aspartate (P less than 0.05, Student's t-test). However, analysis of variance showed no significant carbohydrate effect and plasma AUC values were not significantly affected. These data indicate that carbohydrate affects the metabolism of aspartate and glutamate differently.

Portal and vena caval plasma methionine concentrations in young pigs administered L-methionine, N-acetyl-L-methionine and N-acetyl-D-methionine.

N-Acyl-methionine derivatives have been proposed as replacements for methionine in supplementing food products low in this amino acid. We studied the effects of N-acetyl-L-methionine, N-acetyl-D-methionine and L-methionine loads (2 mmol/kg body weight) on portal and vena caval plasma amino acid concentrations in young pigs (n = 4). L-Methionine loading significantly increased mean (+/- SD) portal and vena caval plasma methionine concentrations from baseline values of 6.44 +/- 1.03 and 6.63 +/- 0.99 mumol/100 ml, respectively, to mean peak values of 340 +/- 75.0 and 265 +/- 49.8 mumol/100 ml, respectively. N-Acetyl-L-methionine loading increased mean peak portal and vena caval plasma methionine concentrations to 291 +/- 85 and 220 +/- 51.6 mumol/100 ml, respectively. N-Acetyl-L-methionine could not be detected in either portal or vena caval plasma. In contrast, N-acetyl-D-methionine loading produced only a small rise in mean peak portal and vena caval plasma methionine concentrations (13.0 +/- 4.31 and 8.62 +/- 1.71 mumol/100 ml, respectively). Concentrations of N-acetyl-D-methionine increased from baseline values of 0 mumol/100 ml to mean peak values of 251 +/- 32.0 and 234 +/- 72.3 mumol/100 ml, respectively, in portal and vena caval plasma. These data explain the poor utilization of N-acetyl-D-methionine as a methionine source.

Effect of meal components on peripheral and portal plasma glutamate levels in young pigs administered large doses of monosodium-L-glutamate.

Mean peak plasma glutamate concentrations and area under the plasma glutamate concentration-time curve are much lower in adult humans ingesting monosodium L-glutamate (MSG) in formula than in water. The present study investigated the effects of individual meal components on portal and vena caval plasma glutamate concentration in young pigs administered MSG. Portal vein catheters and gastrojejunal tubes were placed in four young male pigs, and the animals were allowed to recover. Each animal was then administered four water solutions providing 500 mg/kg body weight MSG in a Latin square design. One solution provided only MSG; the second provided MSG and 1 g/kg body weight metabolizable carbohydrate (partially hydrolyzed corn starch); the third provided MSG and 1 g/kg body weight nonmetabolizable carbohydrate (beta-cellobiose); and the fourth provided MSG and 0.4 g/kg body weight of an amino acid mixture (Aminosyn, Abbott Laboratories, North Chicago, Ill). Mean peak plasma glutamate concentration and area under the plasma glutamate concentration-time curve were significantly lower (P less than 0.05) in both portal and vena caval blood when MSG was administered with metabolizable carbohydrate than when administered in water. Simultaneous ingestion of MSG with nonmetabolizable carbohydrate (beta-cellobiose) or amino acids had no significant effect on either mean peak portal or vena caval plasma glutamate concentration or area under the plasma glutamate concentration-time curves when compared to values observed when MSG was administered alone. The data suggest that metabolizable carbohydrate is the meal component affecting plasma glutamate concentration.

Correlation of aspartate dose, plasma dicarboxylic amino acid concentration, and neuronal necrosis in infant mice.

Eight-day-old mice were administered aspartate at 0, 1.88, 3.76, 4.89, 5.64 and 7.52 mmol/kg body wt and the degree and extent of neuronal necrosis determined. In addition, plasma aspartate and glutamate concentrations were determined at each aspartate dose. Animals administered aspartate at 0, 1.88 and 3.76 mmol/kg body wt did not develop neuronal necrosis. Hypothalamic neuronal necrosis (7.33 +/- 1.52 necrotic neurons/section of maximal damage) was found in 3 of 10 animals administered aspartate at 4.89 mmol/kg body wt. The extent of neuronal necrosis was proportional to dose once a neurotoxic dose of aspartate was reached. All 12 animals administered aspartate at 5.64 mmol/kg body wt developed lesions (49.5 +/- 7.2 necrotic neurons/section of maximal damage). Similarly, all 18 mice administered aspartate at 7.52 mmol/kg developed hypothalamic lesions (80.8 +/- 17.8 necrotic neurons/section of maximal damage). Infant mice administered the highest dose of aspartate not producing neuronal necrosis (3.76 mmol/kg) had a mean (+/- S.D.) peak plasma aspartate concentration of 87 +/- 23 mumol/dl and a mean peak plasma glutamate concentration of 64 +/- 22 mumol/dl. Thus, the toxic threshold for these amino acids must be greater than those values.

Utilization of intravenously administered beta-cellobiose and maltose by young pigs.

Intravenous solutions of glucose oligosaccharides are potential sources of carbohydrate-derived energy for patients requiring intravenous feeding. Relatively little is known about utilization of glucose oligosaccharides linked by beta-glucosidic bonds. We compared the utilization of maltose (alpha-D-glucosyl-1,4-D-glucose) and beta-cellobiose (beta-D-glucosyl-1,4-D-glucose) when administered intravenously (19 g per day) to young pigs for a 5-day period. Animals infused with maltose excreted 15% of the infused disaccharide over the 5-day infusion period. No evidence of maltose accumulation was noted in plasma, and kidney morphology was normal. Animals infused with beta-cellobiose excreted 95% of the infused disaccharide in the urine. The mean (+/- SD) plasma total glucose concentration increased significantly over base-line values of 114 +/- 39 mg/dl to a value of 180 +/- 28 mg/dl during cellobiose infusion, indicating accumulation of cellobiose in body water. Kidney morphology in cellobiose-infused animals was normal. Intravenously infused beta-cellobiose is poorly utilized by the pig when compared with the utilization of its alpha-1,4 linked isomer, maltose.

Thiourea and thiosemicarbazide derivatives structurally related to hexestrol: synthesis and anticancer and other pharmacological properties.

Two novel series of thio compounds bearing internal structural modifications of hexestrol were synthesized as potential anticancer agents. The first contains several N-substituted thiourea functions, and the second contains various N4-substituted-3-thiosemicarbazide moieties in place of one alpha-ethyl group of hexestrol dimethyl ether. The products showed no antileukemic activity in the P-388 lymphocytic leukemia system and did not exhibit any anticonvulsant or estrogenic properties.

Some novel pyrazolone derivatives as anti-inflammatory agents.

Synthesis of three series of compounds namely; 4-(phenazon-4-ylazo)-1-substituted thiocarbamoyl-3-methyl-5-pyrazolones (3-8), 4-(phenazon-4-ylazo)-1-substituted-3-methyl-5-pyrazolones (9-20) and 4-(phenazon-4-ylazo)-1-substituted-3,5-dimethylpyrazoles (21-31) was achieved. These compounds were subjected to anti-inflammatory investigation and it was found that compounds 9 and 10 exhibited a remarkable anti-inflammatory activity, of which the former was the most potent.

Synthesis of novel hexestrol and diethylstilbestrol derivatives as potential anticancer and estrogenic agents.

Two novel series of potential anticancer agents derived from hexestrol and diethylstilbestrol have been synthesized. The first includes several alkylating agents containing sulphonic esters and nitrogen mustard functions attached through various chains to only one phenolic group in hexestrol. The second contains the N1-acetyl-N4-substituted thiosemicarbazide moieties attached to one phenolic group hexestrol or to the two phenolic oxygens in diethylstilbestrol. The tests of some of the products for antileukemic activity in P 388 Lymphocytic Leukemia indicated no significant activity over the parent nuclei. The estrogenic activity of some representative examples of the thiosemicarbazides was found to be dependent on the nature of the N4-substituent in the thiosemicarbazide moiety.

Utilization of L-alanyl-L-tyrosine by nephrectomized rats when infused as part of a total parenteral nutrition regimen.

L-Alanyl-L-tyrosine is well utilized as a tyrosine source in parenterally fed rats. Such utilization may depend upon filtration of peptide into the glomerular filtrate, reabsorption into renal epithelial cells, hydrolysis to component amino acids in or at the surface of epithelial cells, and release of component amino acids to the blood. Bilaterially nephrectomized rats were infused with a parenteral solution providing L-alanyl-L-[U-14C]-tyrosine at 0.5 mmoles/kg over a 2 hour period to test this hypothesis. Despite the absence of kidneys, peptide did not accumulate in plasma or tissues. Plasma and liver tyrosine and alanine levels increased significantly over values noted in animals infused without peptide. One-quarter to one-third of the infused radioactivity was released as 14CO2, with the remainder found in the tissues. Between 15 and 51% of radioactivity in individual tissues was free tyrosine, the remainder was incorporated into protein. Isolation of this protein, acid hydrolysis and simultaneous radioactivity-amino acid analysis demonstrated that 94 to 99% of the radioactivity in protein was tyrosine. The data indicate good utilization of alanyl-tyrosine by nephrectomized rats when administered as part of a total parenteral nutrition regimen.