Metabolism of [3H]ecdysone by isolated tissues of the female ixodid tick Amblyomma hebraeum (Ixodoidea; Ixodidae)

Malpighian tubules, gut, ovaries and carcasses of the adult female tick Amblyomma hebraeum were incubated in vitro in the presence of 2 microM [3H]ecdysone. Organs and media were separately extracted after 6, 24 and 48 h incubations and the patterns of ecdysone metabolites were analyzed by HPLC. Esterase-susceptible apolar metabolites similar to the AP2 already described in the soft tick Ornithodoros moubata and thus presumably corresponding to the same conjugates (C-22 esters with fatty acids) were rapidly produced in all tissues investigated. They were mainly found within the organs but they were also released into the medium to some extent. By contrast, less apolar metabolites corresponding to the AP1 esters were mainly found in the media. Malpighian tubules and gut were the most active organs regarding the conversion of ecdysone into 20-hydroxyecdysone (20E). However, only low quantities of 20E were formed, reaching respectively 12.5% and 11.6% of the total metabolites after 48 h incubations. In the carcass and in the ovary the formation of 20E was only a minor pathway (1.7% and 3.1% of the total metabolites after 48 h). In ovaries we observed a massive conversion of ecdysone into 3-epiecdysone, which (as in insects) presumably proceeded through the intermediate formation of 3-dehydroecdysone. These two compounds were identified among the metabolites by CI/D mass spectrometry. The 3-epimer was released into the media, in contrast with the AP2 which were essentially stored within ovaries. Epimerization was also realized to some extent by carcasses, and again the epimer was released into the culture media. The different pathways are compared with those found in other tick species and in insects, and the significance of the various metabolites is discussed.     

Acyl coenzyme A esters differentially activate cardiac and beta-cell adenosine triphosphate-sensitive potassium channels in a side-chain length-specific manner

Recent evidence demonstrates that long-chain acyl coenzyme A esters (CoAs) activate cardiac and beta-cell plasma-membrane (pmK(ATP)) adenosine triphosphate (ATP)-sensitive potassium channels. In this study, we have investigated the differential effects of acyl CoAs of short and medium side-chain length on cardiac and beta-cell pmK(ATP) isoforms. At the single-channel level, the addition of acyl CoAs of differing side-chain length (2 to 16 carbons) to the inside face of membrane patches from ventricular myocytes caused varying increases in pmK(ATP) channel open probability proportional to increases in acyl side-chain length (20 mumol/L acetyl CoA: 310% +/- 90%, 20 mumol/L decanoyl CoA: 570% +/- 150%). A similar dependence of activation on side-chain length was observed in recombinant pmK(ATP) channels (SUR2A/Kir6.2) with full activation of current requiring both the acyl and CoA moieties in the esterified form. We found the recombinant beta-cell K(ATP) channel (SUR1/Kir6.2) to be much less sensitive to medium-chain acyl CoAs (decanoyl CoA: 124% +/- 15% v 231% +/- 25% in SUR2A/Kir6.2), suggesting a role for the cardiac sulfonylurea receptor, SUR2A, in the molecular mechanism of activation by these compounds. We propose that fatty acid metabolism, and the resultant generation of acyl CoAs of varying side-chain length, may be an important regulator of cellular excitability via interactions with the K(ATP) channel.     

Metabolism of ecdysteroids during the vitellogenesis of the tick Ornithodoros moubata (Ixodoidea, Argasidae): accumulation of apolar metabolites in the eggs

The fate of injected [3H]ecdysone [( 3H]E) and 20-hydroxy-[3H]ecdysone [( 3H]20E) has been investigated in the female tick Ornithodoros moubata (Murray, 1877; sensu Walton, 1962). When injected into fed mated vitellogenic females, [3H]E is converted into [3H]20E and two apolar classes of metabolites, AP1 and AP2. Injected [3H]20E is directly converted into AP1 and AP2. AP2 is incorporated into the ovaries in a high proportion and at the end of the vitellogenic cycle represents about 25% of the total label recovered from the animal. The fate of labeled hormones injected into virgin females which perform an abortive vitellogenic cycle is quite similar. However, the ovaries incorporated less of the AP2 products. Ovaries of mated females cultured in vitro in the presence of [3H]E are able to produce [3H]20E and AP2. AP2 is incorporated, while [3H]20E is mainly found in the medium. Ovaries of virgin females presented a slower rate of transformation and of incorporation of the label. Labeled AP2 is recovered in freshly laid eggs and AP1 in the females after oviposition. AP1 and AP2 can produce [3H]20E, [3H]E, and other minor polar peaks when submitted to hydrolysis by esterase. It is concluded that the female O. moubata possesses a special enzymatic mechanism for transformation of ecdysteroids into apolar products and for selective incorporation of AP2 into the ovaries. These products are present in the freshly laid eggs and could play a role during embryogenesis.     

Cholesterol metabolism in human gallbladder mucosa: relationship to cholesterol gallstone disease and effects of chenodeoxycholic acid and ursodeoxycholic acid treatment.

The objective of this study was to investigate cholesterol metabolism in human gallbladder mucosa, especially in relation to hepatic cholesterol metabolism, gallstone disease and treatment with bile acids. Gallbladder mucosa and liver tissue samples were collected in 44 patients undergoing cholecystectomy; 30 had cholesterol gallstones and the rest were stone free. Ten of the gallstone patients were treated with chenodeoxycholic acid and eight received ursodeoxycholic acid, with a daily dose of 15 mg/kg body wt, for 3 wk before surgery. The 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, governing cholesterol synthesis, was considerably lower in the gallbladder mucosa than in liver tissue (28 +/- 6 and 120 +/- 40 pmol/min/mg protein). The acyl coenzyme A:acyltransferase activity in the gallbladder mucosa catalyzing the esterification of cholesterol was, on the other hand, several times higher than corresponding activity in the liver (92 +/- 23 and 11 +/- 2 pmol/min/mg protein). In the presence of exogenous cholesterol, the acyl coenzyme A:acyltransferase activity increased about twofold in the gallbladder mucosa. The acyl coenzyme A:acyltransferase activity of the gallbladder mucosa from untreated gallstone patients was not stimulated further by the addition of exogenous cholesterol. Otherwise, there were no significant differences in acyl coenzyme A:acyltransferase and 3-hydroxy-3-methylglutaryl coenzyme A reductase activities in the gallbladder mucosa of gallstone patients compared with gallstone-free controls. Treatment with chenodeoxycholic and ursodeoxycholic acids did not affect the 3-hydroxy-3-methylglutaryl coenzyme A reductase activity of the gallbladder mucosa but reduced the acyl coenzyme A:acyltransferase activity by 60% to 65%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidermis as the source of ecdysone in an argasid tick.

Various tissues excised from nymphs of the tick Ornithodoros parkeri at the time of epicuticle deposition were incubated in vitro. The medium from the incubation of salivary glands, coxal glands, synganglion, testis, midgut, and fat body associated with tracheal trunk showed little or no ecdysteroid immunoreactivity. Only medium from incubated integument contained ecdysteroids. The following evidence indicated that epidermal cells are the source of ecdysone: (i) when dorsal and/or ventral integuments were incubated separately, both produced ecdysteroid immunoreactive material during the course of incubation. As compared with the ecdysteroid content in the integument before incubation, the amount of ecdysteroids produced after a 24-h incubation increased 4- to 7-fold; (ii) enzymatic hydrolysis showed that neither highly polar ecdysteroid conjugates nor apolar conjugates were stored in the integument; (iii) histological and scanning electron microscope observations demonstrated that these excised integuments consisted of newly deposited epicuticle and epidermis as well as some fat body cells; (iv) HPLC RIA showed that the integument with associated fat body produced ecdysone and 20-hydroxyecdysone, while the integument produced only ecdysone after removing fat body. Presumably, ecdysone secreted by epidermis was converted into 20-hydroxyecdysone by fat body.     

Ecdysteroid fluctuations during embryogenesis in the giant freshwater prawn, Macrobrachium rosenbergii

Ecdysteroid levels during the embryogenesis of the giant freshwater prawn, Macrobrachium rosenbergii, were determined by radioimmunoassay and high-performance liquid chromatography. Ecdysteroids consisting of significant amounts of 20-hydroxyecdysone and high-polarity products (HPP) and lesser amounts of ecdysone and low-polarity products (LPP) were detected in mature ovaries and newly laid eggs. All ecdysteroid groups decreased gradually during the nauplius phase. With the formation of the compound eye and the appearance of the carapace and other body-like structures, marking morphogenesis to the zoeal stage, embryos showed the beginning of a continuous and dramatic increase in ecdysteroid concentrations sustained until larval hatchout. Ecdysteroid levels at hatchout were above 20-fold greater than ecdysteroid levels in newly laid eggs. More specifically, HPP and 20-hydroxyecdysone increased concomitantly, with a decrease in 20-hydroxyecdysone only at the end of the embryogenic period, while ecdysone and LPP levels remained low or undetectable. It may be postulated that the presence of ecdysteroids in ovaries and eggs represents a reserve of maternal ecdysteroids which are necessary at the commencement of embryonic development; with the differentiation of embryonic tissue capable of ecdysteroid synthesis, ecdysteroids increase rapidly to play a role in later embryonic development.     

Uptake and metabolism of [3H]ecdysone in cultured ovaries of the silkworm, Bombyx mori

Uptake of ecdysone by ovaries of the silkworm, Bombyx mori, was studied by organ culture. [3H]Ecdysone was transported almost linearly into the ovary for up to 3 h of the incubation. The uptake was proportional to the concentration of the labeled ecdysone, unsaturably, at concentrations ranging up to 10(-6) M. Ecdysone which had been transported into the ovary could usually be removed when the ovary was re-transferred to the ecdysone-free medium. Analysis of the transported compounds by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) revealed the marked conversion of ecdysone into 20-hydroxyecdysone, unknown metabolites and conjugated forms. Physiological significance of the metabolic activity of the ovary is discussed with respect to the accumulation of ecdysteroids in the ovary.     

Ecdysone and ecdysterone in physogastric termite queens and eggs of Macrotermes bellicosus and Macrotermes subhyalinus

Physogastric queens and freshly laid eggs of two species of termites (Macrotermes bellicosus and Macrotermes subhyalinus) are found to contain high levels of ecdysteroids (molting hormones) as indicated by radioimmunoassay and Musca bioassay. Ecdysteroids are accumulated in the ovaries of the queen and then stored in the eggs since newly laid eggs contain ecdysteroid concentrations similar to those found in the ovaries. Gas chromatography-mass spectrometry demonstrates that ecdysone (α-ecdysone) as well as ecdysterone (β-ecdysone) are present in queen ovaries and in eggs and that ecdysone is quantitatively the more important ecdysteroid in both ovary and eggs.     

Structure of the cholesteryl ester core of human plasma low density lipoproteins: selective deuteration and neutron small-angle scattering.

The structural arrangement of cholesteryl esters in human plasma low density lipoproteins (LDL) has been studied by selective deuteration and neutron small-angle scattering. LDL were labeled by in vitro exchange with two different kinds of deuterated cholesteryl esters, one labeled in the fatty acyl chain (cholesteryl myristate-d27) and the other in the branched side chain of cholesterol (cholesteryl-25,26,27-d7 oleate). Neutron scattering data from deuterated and protonated LDL were compared to identify the locations of the fatty acyl and cholesterol side chain moieties. Below the thermotropic transition, radii of gyration of 60 A and 70 A were obtained for these two domains, respectively, indicating that the cholesteryl nuclei are situated more distantly from the center than the fatty acyl chains. At 37 degrees C, above the thermotropic transition of the cholesteryl esters in LDL, both parts have similar radii of gyration of approximately 56 A. This information is used in a discussion of possible structural models for the apolar lipid core of LDL.     

Role of the midgut gland in metabolism and excretion of ecdysteroids by lobsters, Homarus americanus.

The chromatographic profile of ecdysteroids (Ecds) from the midgut gland (MG) of juvenile female lobsters, Homarus americanus, was examined using high-performance liquid chromatography (HPLC) and radioimmunoassay (RIA) over four stages of the molt cycle. Upon initial examination, highly polar Ecd conjugates appeared to be the principal metabolites found in all molt stages. HPLC fractions containing apolar Ecds initially exhibited low RIA activity. Upon hydrolysis with a Helix pomatia enzyme preparation and reanalysis, significant amounts of other Ecds were released. Amounts of apolar Ecd conjugates were estimated, at their highest levels, to be at least 50% of the total Ecds in MGs of molt stage D3 lobsters. Only the MG formed significant amounts of apolar Ecds upon in vitro culture with [3H]ecdysone ([3H]E). Epidermis and antennal gland significantly increased their rates of [3H]E metabolism in vitro between molt stages C4 and D1. This result further supports the idea that regulation of ecdysteroid metabolism, at least in selected tissues, may be important in the molt cycle regulation of hormone titers. Using gel filtration column chromatography and sucrose density gradient centrifugation analyses, evidence was found for association of apolar Ecds with a protein(s) from MG cytosol. The protein was estimated to have a molecular weight of 180,000-200,000 and specifically bound apolar Ecds.     

Purification and characterization of fatty acid-binding proteins from human fetal lung

Fatty acid-binding protein (FABP) was isolated, purified, and characterized from developing human fetal lung cytosol by gel filtration and ion-exchange chromatography. FABP exists in three immunochemically identical forms, DE-I, DE-II, and DE-III, having Mr 15,200 +/- 200 each and isoelectric pH 7.8, 6.9, and 5.4, respectively. DE-I is almost lipid-free, DE-II binds mainly long-chain unsaturated fatty acids, and DE-III is an arachidonic acid carrier. One mole of DE-II and DE-III each binds 1 mol of fatty acids noncovalently. Concentrations of all these FABPs increase gradually from early gestation to term. Defatted lung FABP reverses the inhibitory effect of palmitoyl coenzyme A (CoA) (PAL-CoA) on lung glucose-6-phosphate dehydrogenase (G6PD), a key enzyme of the hexose monophosphate (HMP) shunt pathway. This protein when added alone activates the enzyme, suggesting that the original submaximal activity is probably due to the presence of endogenous long-chain fatty acyl CoA esters in the cytosols. As FABP is present in relatively high concentration in most mammalian cells, the potent inhibitory effects of long-chain acyl CoA esters on the HMP shunt pathway in vitro are not seen in intact cells.     

Ovarian immunoreactive beta-endorphin and estrous cycle in the rat

Adult female Sprague-Dawley rats were killed at different stages of a 4-day estrous cycle, and ovaries and anterior pituitaries examined for content of immunoreactive beta-endorphin by RIA and for localization by indirect immunofluorescence. Two anti-beta-endorphin antisera, both recognizing different antigenic determinants of human-beta-endorphin, showed intense immunofluorescence staining of cells localized predominantly in ovarian corpora lutea. At proestrus, both large and small luteal cells stained positively but only the large luteal cells were immunofluorescence positive at other stages of the estrous cycle. In addition, less intense staining of granulosa cells was occasionally observed in secondary and antral follicles; scattered cells in the interstitium were also weakly positive. In contrast, cells of primordial and primary follicles, and those of theca tissue were consistently negative. Ovarian levels of immunoreactive beta-endorphin were found to be lowest at estrus (2.1 +/- 0.18 ng/g; n = 8, mean +/- SE) and significantly raised in stepwise manner over metestrus and diestrus to a peak (approximately 4 X estrous levels) at proestrus; in contrast, immunoreactive beta-endorphin content of anterior pituitaries remained unaltered during the same period. Sephadex G-50 gel chromatography of ovarian extracts revealed three distinct peaks of immunoreactive beta-endorphin, a minor peak in the void volume, and two major peaks of unequal size eluting at mol wt approximately 11.5K and approximately 3.5K. The major species of low molecular weight immunoreactive beta-endorphin on reverse phase HPLC was beta-endorphin1-31. We conclude from the findings that, in adult rat ovaries, luteal, granulosa, and interstitial cells are responsible for the production of immunoreactive beta-endorphin and that this production, being related to the estrous cycle, is presumably under the direct or indirect influence of gonadotropins.     

Pregnancy-associated changes in ovarian immunoreactive beta-endorphin in rats

Ovaries from pregnant and postpartum Sprague-Dawley rats were examined for content of immunoreactive beta-endorphin by radioimmunoassay, and for its localization by the peroxidase-antiperoxidase technique. In addition, the molecular forms of beta-endorphin immunoreactivity were separated by gel chromatography and reverse-phase high performance liquid chromatography (RP-HPLC). Ovaries from rats early in pregnancy showed intense granular cytoplasmic staining of luteal cells, with an even distribution of granular material throughout the cytoplasm. By middle to late pregnancy the staining pattern was changed, with immunoreactive material showing a less granular and unevenly distributed staining pattern and with some areas of the cytoplasm totally devoid of immunoreactive material. The concentrations of immunoreactive beta-endorphin measured during pregnancy were significantly lower than levels in mature non-pregnant rat ovary. The ovarian concentration of immunoreactive beta-endorphin fell progressively during pregnancy and early lactation, returning to normal cyclic rat levels at 20 days post partum. The ovarian concentration of beta-endorphin-like material was lowest at 6 days post partum (0.53 +/- 0.08 ng/g wet weight; mean +/- S.E.M.), representing approximately 10% of the concentration found in pooled ovaries from randomly cyclic adult rats. Gel chromatography revealed only a single peak of immunoreactive beta-endorphin, co-eluting with 3.5 kD molecular weight ovine beta-endorphin (1-31). This contrasts with gel profiles of adult cyclic rat ovary, where large molecular weight species pro-opiomelanocortin (31 kD) and beta-lipotrophin (11.5 kD) are also present. On RP-HPLC the predominant species of low molecular weight immunoreactive material co-eluted with beta-endorphin(1-31).(ABSTRACT TRUNCATED AT 250 WORDS)     

Metabolic and physiological differences between zero-flow and low-flow myocardial ischemia: effects of L-acetylcarnitine

Summary The metabolic and physiologic differences between low-flow and zero-flow ischemia of varying duration were compared in the isolated perfused rat heart. Hearts subjected to 60 and 90 minutes of zero-flow ischemia recovered less cardiac work than hearts subjected to low-flow ischemia. Low-flow ischemia caused a build-up of both myocardial long-chain acyl coenzyme A and acyl carnitine esters, while zero-flow ischemia produced no change in long-chain acyl carnitine and only a transient increase in long-chain acyl coenzyme A. High energy phosphate depletion was greater in zero-flow ischemia. Perfusion with excess free fatty acids decreased the recovery of cardiac work after low-flow ischemia but had no effect after repeated episodes of zero-flow ischemia. L-Acetylcarnitine improved the recovery of cardiac work after low-flow ischemia in hearts perfused with 0.4 and 1.2 mM palmitate. With zero-flow ischemia, L-acetylcarnitine had no effect on the recovery of cardiac work in hearts perfused with 0.4 mM palmitate and a slight but statistically significant effect with 1.2 mM palmitate. Possible protective mechanisms of L-acetylcarnitine against ischemic damage are discussed.     

Circulating bufodienolide and cardenolide sodium pump inhibitors in preeclampsia.

OBJECTIVE: To determine plasma levels of the endogenous bufodienolide Na+/K+ ATPase inhibitor, marinobufagenin-like factor (MBG), in normotensive pregnancy and in preeclampsia, to compare changes of MBG with that of ouabain-like compound (OLC), and to characterize the purified MBG immunoreactive factor from preeclamptic plasma. DESIGN AND METHODS: Consecutive sample study. The levels of MBG and OLC compounds were measured in extracted plasma by solid phase fluoroimmunoassays. MBG and ouabain immunoreactive materials were partially purified from preeclamptic plasma via reverse-phase high-performance liquid chromatography (HPLC) and studied for their ability to cross react with MBG and ouabain antibodies, and to inhibit the Na+/K+ ATPase from human mesenteric arteries. Vasoconstrictor effect of authentic MBG was studied in isolated rings of human umbilical arteries. RESULTS: In 11 nonpregnant control individuals, plasma concentrations of MBG and OLC were 0.190+/-0.04 nmol/l and 0.297+/-0.037 nmol/l, respectively. In the third trimester of noncomplicated pregnancy (n = 6), plasma MBG increased (0.625+/-0.067 nmol/l, P<0.05), and OLC did not (0.32+/-0.07 nmol/l). In 15 patients with preeclampsia, plasma levels of both MBG and OLC increased dramatically (2.63+/-0.10 nmol/l and 0.697+/-0.16 nmol/l, respectively, P<0.01 versus both control groups). When fractionated by reverse phase HPLC, OLC was eluted by 18% acetonitrile, and MBG by 48% acetonitrile. Serially diluted samples of MBG and OLC immunoreactive materials from HPLC fractions reacted with MBG and ouabain antibody in solid phase immunoassay in a concentration dependent fashion. Authentic MBG caused contractile responses of isolated rings of human mesenteric arteries in a concentration-dependent manner. Similarly to the authentic MBG, HPLC purified MBG immunoreactive material from preeclamptic plasma inhibited Na+/K+ ATPase purified from human mesenteric artery. CONCLUSIONS: Our observations demonstrate the coexistence of two endogenous cardiotonic steroids in preeclamptic plasma, a more polar OLC and a less polar MBG-like compound. Substantial increases in plasma OLC and MBG immunoreactivity in preeclampsia, along with the vasoconstrictor properties of authentic MBG and Na+,K+ ATPase inhibitory activity of human MBG immunoreactive factor, suggest, that in preeclampsia, plasma concentrations of MBG are enough to substantially inhibit the sodium pump in cardiovascular tissues, and are in accordance with the views attributing endogenous digitalis-like factors a pathogenic role in the preeclamptic hypertension.     

Improvement in the regulation of cellular cholesterologenesis in diabetes: the effect of reduction in serum cholesterol by simvastatin.

Cellular cholesterol homeostasis was examined in 11 hypercholesterolaemic Type 2 diabetic patients prior to and following reduction of serum cholesterol using simvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase. Following 12 weeks of treatment with simvastatin (10-40 mg day-1), serum cholesterol decreased by 30 +/- 3% from 7.8 +/- 0.2 mmol l-1 to 5.5 +/- 0.2 mmol l-1 (p less than 0.001) and LDL-cholesterol by 35 +/- 4% from 5.7 +/- 0.2 to 3.6 +/- 0.1 mmol l-1 (p less than 0.001). The esterified/free cholesterol ratio in LDL also decreased from 2.75 +/- 0.18 to 1.94 +/- 0.10 (p less than 0.01) after treatment. Cellular cholesterol synthesis, measured by [14C] acetate incorporation into mononuclear leucocytes, decreased by 39 +/- 11% from 231 +/- 13 to 140 +/- 25 mumol g-protein-1 (p less than 0.01). The degree of suppression of [14C]acetate incorporation into cholesterol in normal mononuclear cells by diabetic patients' LDL increased from 32.1 +/- 4.0% to 48.8 +/- 2.5% (p less than 0.001) following simvastatin. The activity of acyl coenzyme A:cholesterol-0-acyltransferase (ACAT) increased significantly by 55 +/- 18% (p less than 0.05) after treatment. Cholesterol synthesis in patients' mononuclear cells correlated positively (r = 0.66, p less than 0.05) with the esterified/free cholesterol ratio of their LDL, while suppression of cholesterol synthesis by patients' LDL correlated negatively (r = -0.64, p less than 0.05) with the esterified/free cholesterol ratio of the LDL following treatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in ecdysone content during postembryonic development of the wax moth, Galleria mellonella: the role of the ovary

The ecdysone titers of representative developmental stages during the life cycle of Galleria mellonella were determined by radioimmunoassay. During the last larval instar two ecdysone peaks are present, the first peak occurring relatively late in the instar concurrent with the initiation of wandering and the second separated from the first by only 1.5 days. The second increase in ecdysone titer marks larval-pupal apolysis and is only slightly larger than the first peak in contrast to studies on other Lepidoptera. Two days after pupation a large ecdysone peak occurs denoting the beginning of pharate adult development and the titer declines thereafter. In female pharate adults, but not in males, the ecdysone titer rises to the maximum for the life cycle at about the time of adult eclosion and then declines slowly during the next 4 days. When larvae are gonadectomized, the resulting females no longer yield the ecdysone peak found under normal conditions at about the time of pupal-adult ecdysis. Extraction of ovaries from late pharate adult G. mellonella and analyses of ovarian in vitro secretory kinetics demonstrate unequivocally that the developing ovary synthesizes the ecdysones characterizing the female at the time of adult emergence. Further studies revealed that most of the ovarian ecdysones are associated with mature oocytes and are probably synthesized by the nurse and/or follicle cells. The ovarian ecdysoones are a mixture of α- and β-ecdysone and another molecular species tentatively identified as 2-deoxy-α-ecdysone.     

Effect of chronic ethanol ingestion on hepatic and intestinal acyl coenzyme a:cholesterol acyltransferase and 3-hydroxy-3-methylglutaryl coenzyme a reductase in the rat

Two groups of rats were pair-fed diets in which 36% of the calories were provided by either ethanol or dextrimaltose. After 60 days on these liquid diets, rats fed ethanol were significantly smaller than control rats fed dextrimaltose. Serum cholesterol levels in ethanol-fed animals were 20% higher than control rats. Cholestasis was not observed histologically, and serum alkaline phosphatase and bilirubin levels were the same in both groups. The livers of animals ingesting ethanol accumulated triglycerides and cholesterol. The increase in cholesterol was due to an increase in cholesteryl esters. The cholesterol content of liver microsomes, however, was unchanged by ethanol feeding. A small increase in unesterified cholesterol was observed in intestinal microsomes prepared from animals receiving ethanol. Microsomal fatty acids in liver and intestine were unchanged by the ethanol diet. Chronic ingestion of ethanol in these animals failed to change acyl coenzyme A:cholesterol acyltransferase or 3-hydroxy-3-methylglutaryl-coenzyme A reductase activities in the intestine. In contrast, the activities of acyl coenzyme A:cholesterol acyltransferase and 3-hydroxy-3-methylglutaryl-coenzyme A reductase were significantly increased in the livers of rats receiving ethanol. Thus, the chronic ingestion of ethanol caused a marked accumulation of hepatic cholesteryl esters. This was associated with a significant increase in the activities of enzymes that control the rates of both cholesterol synthesis and cholesterol esterification in the liver. These observed changes in enzyme activities may contribute to the lipid accumulation which occurs in these livers. Chronic ethanol consumption did not alter cholesterol metabolism in the intestine.     

Follicle-stimulating hormone increases primordial follicle reserve in mature female hypogonadal mice

Ovarian primordial follicle reserve is considered hormonally independent or subject to depletion by FSH-driven follicle recruitment. To explore specific in vivo effects of FSH on early follicle populations in the absence of luteinizing hormone (LH) activity, we examined mature hypogonadal (hpg), gonadotrophin-deficient mice expressing transgenic (tg) human FSH. Sustained expression of tg-FSH (5.3 +/- 0.3 IU/l) increased ovary weights fourfold and significantly elevated total primordial follicle numbers twofold in tg-FSH hpg (4209 +/- 457) relative to non-tg hpg (2079 +/- 391) and wild-type (2043 +/- 195) age-matched ovaries. Absolute primary follicle numbers in tg-FSH hpg ovaries were similar to non-tg hpg and wild-type ovaries. Furthermore, tg-FSH quantitatively increased secondary and antral follicles in hpg ovaries to numbers equivalent to wild-type, but did not induce ovulation, indicating a selective FSH response without LH. Circulating inhibin B and inhibin A levels were significantly increased in tg-FSH hpg females compared with hpg controls, and inhibin B correlated with antral number, consistent with FSH-driven antral follicle formation. These findings revealed that sustained pituitary-independent FSH activity, in the absence of endogenous gonadotrophins, promotes an increase in primordial follicle reserve despite also stimulating follicular growth in mature females. Therefore, the tg-FSH hpg ovary presents a novel paradigm to evaluate specific gonadotrophin effects on follicle reserve and recruitment.     

Synthesis of coenzyme A ester of retinoic acid: intermediate in vitamin A metabolism.

Coenzyme A esters of all-trans- and 13-cis-retinoic acid were synthesized for use in studying vitamin A metabolism. The esters were obtained by two different synthetic methods starting from retinoic acids, which were converted to activated succinimidyl esters or anhydrides. These in turn were coupled with coenzyme A to form their respective thioesters. The retinoyl coenzyme A esters were purified by reverse-phase high performance liquid chromatography.