Effects of long-term growth hormone therapy on adrenal steroidogenesis in Turner syndrome

Nature's most potent molecules are produced by enzyme-catalysed reactions, coupled with the natural selection of those products that possess optimal biological activity. Combinatorial biocatalysis harnesses the natural diversity of enzymatic reactions for the iterative synthesis of organic libraries. Iterative reactions can be performed using isolated enzymes or whole cells, in natural and unnatural environments, and on substrates in solution or on a solid phase. Combinatorial biocatalysis is a powerful addition to the expanding array of combinatorial methods for the generation and optimization of lead compounds in drug discovery and development.     

Short-term treatment with low-dose pravastatin attenuates oxidative susceptibility of low-density lipoprotein in hypercholesterolemic patients

The effects of treatment with low-dose 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor pravastatin on the changes of chemical composition and in vitro oxidative susceptibility of low-density lipoprotein (LDL) were studied in 20 type Ila hyperlipidemic patients with a plasma total cholesterol level > 240 mg/dL at the end of a diet control period for 3 months using the American Heart Association recommended step I diet. Treatment with pravastatin in a dose of 5 mg twice daily for 4 weeks resulted in lowering plasma total and LDL cholesterol levels by 17.0% and 22.9%, respectively. There was no further decline in plasma lipid thereafter. Chemical composition analysis showed that LDL particles did not contain significantly less cholesterol and thiobarbituric acid reactive substances (TBARS) until the end of 8 weeks (130.6 +/- 17.8 vs. 106.6 +/- 37.1 mg/mg protein, P < 0.05 and 0.16 +/- 0.06 vs. 0.08 +/- 0.02 nmol/mg protein, P < 0.005, respectively). Vitamin E, phospholipid, and triglyceride contents remained at the same levels throughout the study. In terms of oxidative kinetics, lag time and time to maximal diene concentration were not prolonged during the treatment period for 12 weeks, while total diene concentration and reaction rate were not significantly reduced until 8 weeks of treatment. Plasma enzyme activity of glutathione reductase and peroxidase, as well as the whole blood level of reduced and oxidized glutathione, remained similar during the study. In conclusion, pravastatin, at the low dose of 5 mg twice daily, produced a significant decline in plasma lipid levels to a steady-state range by 4 weeks; however, 8-weeks treatment is necessary to reduce the cholesterol and TBARS content, as well as to attenuate the oxidative susceptibility of LDL. These effects are not related to the antioxidant glutathione.     

The hypothalamus-pituitary-gonad axis and testicular function in male patients after treatment for haematological malignancies

In this study including 26 patients with dyslipoproteinemia classified IIa, we evaluated biochemical and clinical safety of Nomegestrol acetate (Lutenyl) used for its antigonadotrophin property. It was administered alone, during 3 cycles at the dose of 5 mg/d for 21 days by cycle and then it was associated (at the same sequence and dose), without any wash out, for the next 6 cycles, with a 17 beta estradiol patch (Estraderm TTS 50), 50 micrograms/d from the 11th to the 21st day of each cycle. Nomegestrol acetate, alone, had no significant effect on glycemia, antithrombin III, triglycerides, total cholesterol, apoprotein A1, and LpA1 values compared to those at baseline but apoprotein B and Lp (a) values tended to decrease slightly. Serum progesterone levels were collapsed, and FSH values were low. Weight and blood pressure remained constant. Adding 17 beta estradiol enabled to significantly decrease and normalize the apoprotein B values after the first 3 cycles compared to the baseline values, then these values remained constant during the next 3 cycles. There was no effect on the other parameters (except for a significant increase in plasmatic estradiol values) on the antigonadotrophin property of Nomegestrol acetate, nor on weight and blood pressure which remained constant. Moreover, we observed an important decrease in the rate of amenorrheic cycles compared to those with Nomegestrol acetate alone.     

The effectiveness and safety of low dose pravastatin in elderly hypertensive hypercholesterolemic subjects on antihypertensive therapy

To evaluate the efficacy and safety of low dose (10 mg) pravastatin in hypercholesterolemic, hypertensive elderly subjects undergoing antihypertensive treatment, a randomized, double-blind, placebo-controlled 6-month trial was conducted. The subjects had a total plasma cholesterol of at least 250 mg/dL and had been, for at least 3 months, consuming a standard lipid-lowering diet (American Heart Association Step 1 Diet). Sixty elderly hypertensive patients randomly received placebo (n = 30) or pravastatin (n = 30) treatment. The dosage consisted of 10 mg of pravastatin daily during the 6-month trial. Over that period, in the pravastatin group, plasma levels of total cholesterol and LDL-cholesterol significantly (P < .01) dropped (-20% and -25%, respectively) compared to the placebo group. The plasma level of HDL-cholesterol increased (+5%) while triglycerides slightly decreased (-8%) (P < .05). No serious side effects occurred, and pravastatin was generally tolerated. Fasting hyperinsulinemia (11.0 +/- 0.8 v 9.3 +/- 0.7 microU/mL; P = .06) also improved, although not significantly, after 6 months of pravastatin therapy. Results from this study confirmed that a low dose (10 mg) of pravastatin daily is a safe and effective method of reducing plasma total and LDL-cholesterol in hypercholesterolemic, hypertensive elderly patients who are on concurrent antihypertensive drug therapy.     

The involvement of nitric oxide in stress-impaired testicular steroidogenesis

The participation of the nitric oxide (NO) pathway in downregulation of testicular steroidogenesis in normal and stressed rats was investigated both in vivo and in vitro. In Leydig cells from normal animals, isosorbide dinitrate, an NO donor, decreased the human chorionic gonadotropin (CG)-stimulated and progesterone-derived androgen production. Also, the intratesticular injection of a precursor of NO, arginine (10 mg/testis), transiently decreased serum androgen levels and inhibited human CG-stimulated androgen production in acute testicular cultures. These effects were eliminated in rats cotreated with Nomega-nitro-L-arginine methyl ester (L-NAME) (2 X 600 microg/each testis). Acute immobilization stress (2 h) decreased serum androgen levels and inhibited human CG-stimulated androgen production in vitro. These effects were accompanied by a significant increase in nitrite, a stable oxidation product of NO, in testicular cultures. Bilateral intratesticular injection of L-NAME prevented the stress-induced decrease of human CG-stimulated androgen production, and significantly reduced the nitrite levels. These results implicate NO in normal and stress-impaired testicular steroidogenesis.     

Effects of pravastatin on thoracic aortic atherosclerosis in patients with heterozygous familial hypercholesterolemia

Data regarding the effects of plasma lipid lowering on the evolution of thoracic aortic atherosclerosis (TAA) are scarce. In this study, we performed transesophageal echocardiography to characterize TAA in 16 newly diagnosed patients with heterozygous familial hypercholesterolemia and to follow its evolution after 2 years of statin treatment. TAA was graded as follows: grade I = normal intima; grade II = increased intimal echo density without thickening; grade IIIA = increased intimal echo density with single atheromatous plaque < or = 3 mm; grade IIIB = multiple plaques < or = 3mm; grade IV = > or = 1 plaque >3 mm; and grade V = mobile or ulcerated plaques. Baseline aortic intimal morphology was grade I in one patient, grade II in 4, grade IIIA in 6, grade IIIB in 3, and grade IV in 2 patients. Hypolipidemic treatment resulted in significant reductions in plasma total cholesterol and low-density lipoprotein (LDL) cholesterol. Follow-up aortic morphology was grade I in 5 patients, grade II in 2, grade IIIA in 3, grade IIIB in 3, and grade IV in 3 patients. TAA remained stable in 7 patients, progressed in 3, and regressed in 6 patients. TAA evolved in a uniform manner in the ascending aorta, aortic arch, and descending aorta. Patients with TAA regression were younger (39+/-14 vs 52+/-8 years, p=0.038) and had a greater decrease in plasma LDL cholesterol as a result of treatment (138+/-56 vs 73+/-55 mg/dl, p=0.036) than patients with TAA stability or progression. These observations support the hypothesis that hypolipidemic treatment may favorably affect the course of TAA in patients with heterozygous familial hypercholesterolemia.     

Comparison of hypercholesterolemic men and women at high risk for atherosclerosis. Study of risk factors and response to pravastatin treatment

BACKGROUND: Ornithine decarboxylase (ODC; EC 4.1.1.17) is the first rate-limiting enzyme in the biosynthesis of polyamines. ODC protein has a characteristic amino acid sequence, the PEST sequence, which is related to the enzyme's rapid degradation. ODC cDNA prepared from human hepatoma tissues has been reported to show nonsense or missense mutations. METHODS: We examined somatic mutations of ODC cDNA by RT-PCR-SSCP analysis and mRNA expressions by RT-PCR in 50 colorectal cancer tissues to investigate the involvement of ODC gene alterations in colorectal cancers. RESULTS: Increased expression of the ODC gene was observed in 36 cases (86%) out of the 42 examined by RT-PCR. In one case, a missense mutation was found in the cancer tissue but not in normal mucosa. The missense mutation from Asp to Asn at codon 424, in the PEST region, possibly stabilizes the ODC protein. In colorectal cancer, replication error and a germline mutation in hMSH2 gene were observed. CONCLUSIONS: The missense mutation at codon 424 is speculated to be a cause of stabilization and a passenger mutation owing to the mutator phenotype. Since only one of 50 colorectal cancers exhibited a missense mutation of the ODC gene, mutations in ODC gene are not frequent in colorectal cancer. The increased expression of the ODC gene was noted in 86% of colorectal cancer tissues by RT-PCR, however, it was not due to point mutations in ODC coding exons.     

Effect of pravastatin treatment on glucose, insulin, and lipoprotein metabolism in patients with hypercholesterolemia

Treatment of patients with type IIA hyperlipoproteinemia (HLP) with pravastatin for 3 months led to significant decreases (p < 0.001) in total cholesterol (7.18 +/- 0.30 to 5.75 +/- 0.30 mmol/L), LDL cholesterol (5.56 +/- 0.33 to 4.02 +/- 0.32 mmol/L), and ratio of total cholesterol to HDL cholesterol (6.5 +/- 0.4 to 4.6 +/- 0.4). Decreases of a similar magnitude were also seen in patients with type IIB HLP. Plasma glucose and insulin concentrations after an oral glucose load and from 8 AM to 4PM in response to meals were higher in patients with Type IIB HLP, who also had higher steady-state plasma glucose concentrations after an infusion of somatostatin, insulin, and glucose (12.4 +/- 1 vs 5.5 +/- 0.8 mmol/L, p < 0.001). Because steady-state plasma insulin concentrations were similar in both groups, patients with type IIB HLP were relatively insulin resistant. Furthermore, day-long plasma glucose concentrations and insulin resistance were modestly, but significantly (p < 0.01), greater after treatment in both groups. In conclusion, LDL cholesterol metabolism improved in hypercholesterolemic subjects treated with pravastatin, but the hypertriglyceridemia, insulin resistance, relative glucose intolerance, and hyperinsulinemia present in patients with type IIB HLP either did not improve with treatment or was somewhat worse.     

Comparative characteristics of steroidogenesis and its biorhythm in the hyperfunctioning adrenal cortex

The paper summarizes the results od several studies of the daily rhythms of steroid hormones in patients with ACTH-dependent Itsenko-Cushing's disease (CD) and congenital adrenal hyperplasia (late-onset forms) (CAH). Normal daily rhythms of adrenal C21- and C19-steroids and ACTH were observed in 23.5% of CD patients. CAH patients had the marked daily rhythms of adrenal androgens and testosterone which were typical of those of cortisole. The ratios of steroid hormones to its precursors provide evidence for enhanced activities of 17-, 11 beta- and 18-hydroxylases in CD patients and normal enzymatic activities in CAH patients, whereas 21-hydroxylase being an exception.     

The involvement of innervation in the regulation of fetal adrenal steroidogenesis

Over the last decade, great interest has been generated in evaluation of the extent of neural control of the adrenal cortex and in adrenal cortical/medullary paracrine interactions. The purpose of this review is to summarize current knowledge of fetal adrenal cortical innervation and to present an overview of those studies of fetal adrenal function indicating that adrenal innervation plays a functional role in the control of glucocorticoid secretion under basal conditions and in response to a variety of homeostatic challenges. It will be helpful in understanding both the innervation of the adrenal cortex and the role of adrenal innervation in steroidogenesis during fetal development to briefly review experimental studies that have shed light on adrenal steroidogenesis during postnatal life. This is helpful for two reasons: 1) the vast majority of studies of adrenal innervation and its effect on steroidogenesis have utilized postnatal animals and 2) since the fetus is preparing for postnatal life, evaluating the level of function achieved postnatally provides crucial insights into the developmental stages of adrenal innervation and its role in steroidogenesis in preparing the fetus for an independent postnatal existence.     

Cytosolic and mitochondrial proteins as possible targets of cycloheximide effect on adrenal steroidogenesis

We investigated the in vitro and in vivo interaction between amiodarone and lidocaine. The interaction on a molecular level was first studied in microsomes from 11 human livers. Close correlations between amiodarone N-monodesethylase activities and (a) the amounts of cytochrome P-4503A4 (CYP3A4), and (b) the rates of lidocaine N-monodesethylation were observed. Lidocaine inhibited amiodarone N-monodesethylation (Ki = 120 microM) competitively; inversely, amiodarone suppressed lidocaine N-monodesethylase activity in the same manner (Ki = 47 microM). Moreover, the metabolite N-monodesethylamiodarone (DEA) was stable and inhibited lidocaine metabolism in a concentration-dependent manner. The in vivo interaction was investigated in 6 cardiac patients. Each of them received a dose of 1 mg/kg lidocaine hydrochloride intravenously (i.v.) on three different occasions: before amiodarone treatment (control), and after cumulative doses of 3 g (phase I) and 13 g (phase II), respectively, amiodarone hydrochloride. The analysis of lidocaine pharmacokinetics showed an increase in lidocaine area under the curve (AUC) when amiodarone was administered, whereas that of N-monodesethylated lidocaine decreased. Moreover, the systemic clearance of lidocaine decreased, while the elimination half-life (t1/2) and the distribution volume at steady state of lidocaine remained unchanged. The pharmacokinetic parameters during phase II were the same as those during phase 1, indicating that the interaction had already occurred early in the loading phase of amiodarone administration. The interaction between amiodarone and lidocaine may be explained by the inhibition of CYP3A4 by amiodarone and/or by its main metabolite DEA.     

Effects of long-term food reduction on the hypothalamus-pituitary-thyroid axis in male and female rats

The reduced thyroid activity during short-term starvation is associated with a lowered hypothalamic synthesis and secretion of TRH. However, little is known about the cause of the reduced thyroid function during prolonged malnutrition. We have therefore studied the effects of food reduction to one-third of normal (FR33) on the hypothalamus-pituitary-thyroid axis of male and female Wistar rats. After 3 weeks body weights of FR33 rats were almost 50% lower than those of controls. In both sexes, FR33 caused marked increases in serum corticosterone, and decreases in serum TSH, thyroxine (T4), free T4, tri-iodothyronine (T3) and free T3. While the free T3 fraction (FFT3) in serum decreased, the free T4 fraction (FFT4) tended to increase. Electrophoretic analysis indicated that decreased FFT3 was correlated with an increased thyroxine-binding globulin, while the increase in FFT4 seemed due to a decreased thyroxine-binding prealbumin binding capacity. Total RNA and proTRH mRNA in the hypothalamus were not affected by FR33. Median eminence and posterior pituitary TRH content tended to increase in FR33 rats, suggesting that hypothalamic TRH release is reduced in FR33 rats. Anterior pituitary TSH content was decreased by FR33 in both sexes, but pituitary TSH beta mRNA and TRH receptor status were not affected except for increased pituitary TSH beta mRNA in female FR33 rats. Although FR33 had no effect on pituitary weight, pituitary RNA and membrane protein content in FR33 rats were 50-70% lower than values in controls. In conclusion, prolonged food reduction suppresses the pituitary-thyroid axis in rats. In contrast to short-term food deprivation, the mechanism whereby serum TSH is suppressed does not appear to involve decreases in proTRH gene expression, but may include effects on pituitary mRNA translation. Our results further support the hypothesis that TSH release may be lowered by increased corticosterone secretion, although the mechanism of this effect may differ between acute starvation and prolonged food reduction.     

Effects of treatment of varicocele on male sterility. Fertility of 84 operated patients

84 men with primary sterility averaging 3.5 years and secondary sterility for 5.5 years with varicocele were treated with Yvanissevich's operation. 43 impregnated their wives within about 15 months, resulting in 33 term births, 9 miscarriages, and 1 extrauterine pregnancy. 80% of the spermograms were oligospermic before the operation. 50% of those whose wives conceived showed improved spermograms, and 37% of the men whose wives failed to conceive had improved spermograms. 50% of the men with normal testicles, 33% of those with unilateral testicular hypoplasia, and 40% of those with bilateral hypoplasia showed improved spermograms. Long thin spermatozoa did not appear to be characteristic of men with varicocele.     

Effects of cyproterone acetate on FSH and testosterone influenced spermatogenesis, steroidogenesis and epididymis in the Indian wall lizard, Hemidactylus flaviviridis (Ruppell)

The effects of FSH, testosterone and either cyproterone acetate (CPA) alone or in combination with FSH or testosterone on testis and epididymis in male lizards were studied histologically and histochemically during recrudescent phase to find out whether the onset of spermatogenesis is androgen dependent or FSH dependent. The testes of control lizards consisted of mainly spermatogonia, a few primary spermatocytes and secondary spermatocytes rarely. The interstitial or Leydig cells were atrophied. FSH treatment induced spermatogenic activity substantially as indicated by increase in number of primary and secondary spermatocytes and transformation of secondary spermatocytes into spermatids and into spermatozoa in a few cases. Besides, steroidogenic activity was also remarkably stimulated as evidences by considerable depletion of sudanophilic lipid and an increase in Delta5-3beta-hydroxysteroid dehydrogenase enzyme activity in Leydig cells. However, testosterone treatment resulted in the inhibition of spermatogenesis. A significant inhibition of spermatogenesis was noted in lizards treated either with CPA alone or in combination with FSH. The inhibitory effect of CPA on spermatogenesis was increased when it was given in combination with testosterone. The results indicate that onset of spermatogenic activity is dependent on FSH (or FSH-like protein), but not on the androgen. The ductus epididymidis in control lizards was regressed with low cuboidal epithelium. The lumen of the tubules was totally devoid of secretory material and spermatozoa. FSH treatment induced a marked hypertrophy in epididymidis. The lumen became filled with secretory material mixed with spermatozoa. The hypertrophy in epididymidis was also recorded after the treatment with testosterone, but the degree of induction was not to that extent as noted in FSH treated ones. However, CPA injected either with FSH or with testosterone resulted in the profound atrophy in epididymidis.     

Sexual activity and anomalous spermatogenesis in young male silver foxes

The total number of spermatozoa in ejaculate of males with normal sexual activity was 165,647,5 million and the mean percentage of morphologically abnormal spermatozoa was 21,64,4%. The percentage of morphologically defective spermatozoa in sexually inactive males was significantly lower than in sexually active ones.     

Patterns of long-term steroidogenesis stimulation by ACTH and phorbol ester

Adrenocorticotropic hormone (ACTH) triggers well-defined responses in Y-1 cells. Among them is steroidogenesis stimulation. We have previously shown that phorbol 12-myristate 13-acetate (PMA), an activator of the calcium- and phospholipid-dependent protein kinase (PKC) is able to mimic all the responses triggered by ACTH in these cells, including steroidogenesis stimulation. Short (2 h) treatment with PMA leads to only 20-30% of the maximal steroidogenesis stimulation obtained with ACTH. However, the steroid secretion in the 2 h that follows the short-term (2 h) PMA treatment reaches the same levels as observed with ACTH, i.e., a 12- to 15-fold increase. We also show that this effect is restricted to cells treated with PMA for up to 4 h, while treatment for longer periods of time causes a reduction of the steroid biosynthesis rate, an effect that is not observed in cells treated with ACTH or N6,2'-0-dibutyryladenosine 3',5'-cyclic monophosphate (dcAMP). These results suggest that activation of PKC can elicit the first phase of ACTH steroidogenesis stimulation, but not the second one, which strictly depends on activation of cAMP-dependent protein kinase.     

Clozapine in long-term treatment of schizophrenic patients

Clozapine has advantages over standard antipsychotics in refractory schizophrenia. Studies on the efficacy of clozapine in the maintenance treatment are sparse and suffer from methodological limitations. Despite this fact clozapine ranked second in a survey dealing with the preference of this antipsychotic in the long-term treatment of schizophrenia. Doctors report on using a mean of 130 mg/d in this indication which is considerably less than the doses used in most of the published long-term trials. The discrepancy between the popularity of clozapine and the lack of sound empirical data on its long-term efficacy is discussed.     

Cytochrome c oxidase in rat adrenal and liver: effects of anti-androgen treatment and studies in testicular feminized rats

The role of androgen receptors in androgen-induced changes in rat adrenocortical and liver cytochrome c oxidase (COX) has been investigated. The anti-androgen flutamide, blunted the increase in COX activity and COX subunits II/III and IV, that is seen with androgen treatment. Testicular feminized (Tfm) rats had levels of COX activity and COX subunits II/II and IV in adrenal cortex and liver that were intermediate between the high levels found in normal male rats and the lower levels of normal female rats. These data suggest that androgen effects on adrenal and liver COX are mediated through interactions with androgen receptors known to be present in these issues. However, the observed changes in COX activity and COX subunits were not accompanied by altered levels of mRNAs encoding for COX II or COX IV.