Effects of 3,3-dipyridylmethyl-1-phenyl-2-indolinone on gamma-aminobutyric acid elicited chloride current of snail central neuron

The effects of (1) gamma-aminobutyric acid (GABA) on the excitable membrane and (2) DPMPI (3,3-dipyridylmethyl-1-phenyl-2-indolinone) on the microperfused GABA elicited currents were investigated on central LP5 neuron of giant African snail, Achatina fulica Ferussac, with conventional voltage-clamp technique. GABA elicited an inward current of LP5 neuron by a concentration and voltage dependent manner. Muscimol, GABAA receptor agonist, did, while baclofen, GABAB receptor agonist, did not, elicit the membrane current on the neuron. The GABA elicited currents in LP5 neuron were blocked by picrotoxin, a GABAA receptor ion channel complex antagonist while the currents were not blocked by phaclofen, a GABAB receptor antagonist. The results suggested that the GABA elicited current in LP5 neuron was mainly due to activation of GABAA receptor. DPMPI increased the frequency of the spontaneously generated action potential of the neuron. In the voltage clamped neuron, DPMPI decreased the GABA elicited responses by a concentration dependent manner. DPMPI altered neither the reversal potential of GABA elicited current, nor the membrane resistance of the excitable membrane of central LP5 neuron. The results concluded that DPMPI altered the GABAA activated receptor ionic channel complex of the LP5 neuron.

Polymorphisms and intron sequences flanking the alternatively spliced 8-amino-acid exon of gamma2 subunit gene for GABAA receptors

Gamma-amminobutyric acid (GABA) is a major inhibitory neurotransmitter. Two alternatively spliced forms of the gamma2 subunit of GABAA receptor (gamma2L and gamma2S), which differ by an exon of eight amino acids, show different sensitivities to modulatory effects of ethanol on receptor activities. A 2.7 kb DNA fragment and an 1.7 kb DNA fragment covering respectively the introns upstream and downstream from the 8-amino-acid exon were obtained through PCR-amplification of human genomic DNA using primers derived from cDNA sequences. Total sequencing of these fragments showed a composite 4.2 kb segment containing the 8-amino-acid exon and consensus sequences for RNA splice junctions. Restriction fragment length polymorphisms (RFLP) based on NciI restriction digestion were found among Chinese in Taiwan. This RFLP provides a useful DNA marker for allelic association or linkage analyses of the role of GABAA receptors in predisposition to alcoholism or other neuropsychiatric disorders.

Identification, purification, and partial characterization of a factor from rabbit serum that inhibits prolactin secretion by pituitary cells cultured in vitro

A biological factor that inhibited prolactin secretion by pituitary cells cultured in vitro was identified, purified, and partially characterized from normal rabbit serum. This biological factor was also found to potentiate dopamine-mediated aortic contraction using rabbit aortic strips in vitro. Following SDS-PAGE, this factor displayed an apparent Mr of 17 kDa, which is different from the Mr of most known endogenous factors having an inhibiting activity on pituitary prolactin secretion, suggesting that this may be a yet-to-be identified novel molecule.

Synthesis and structure-opioid activity relationships of trans-(+/-)-3,4-dichloro-N-methyl-N-[4- or 5-hydroxy-2-(1-pyrrolidiny)cyclohexyl]benzeneacetamides

To explore the effects of attaching a hydroxy function to the cyclohexane ring of kappa-selective opioid N-[2-(1-pyrrolidinyl)cyclohexyl]benzeneacetamides, trans-(+/-)-3,4-dichloro-N-methyl-N-[4- or 5-hydroxy-2-(1-pyrrolidiny)cyclohexyl]benzeneacetamides (1-4) and their benzoates (5-8) have been synthesized in a divergent and stereoselective manner. When compared with the parent compound U-50488, hydroxy derivatives 1-4 maintained high selectivity towards the kappa-opioid receptor (mu/kappa ratio = 24 to > 91); while displaying significant reduction in binding affinity (Ki,kappa = 75-218 nM). The lowest kappa-affinity was observed with compound 4, where the hydroxy group is attached at the 5-axial or 5-beta position. Further reduction in kappa-affinity was observed when the hydroxy function was benzoylated. However, the 4 beta, 5 alpha, and 5 beta isomers (6-8) maintained varying degrees of kappa-selectivity; the 4 alpha-isomer compound 5, with its benzoate moiety situated at the 4-axial position is now a moderately potent mu-selective opioid (Ki,mu = 168 nM, mu/kappa = 0.076). The result suggest the importance of lipophilicity in binding to opioid receptors and the presence of a specific lipophilic binding site on the mu-opioid receptor.

Identification, isolation, and characterization of a 41-kilodalton protein from rat germ cell-conditioned medium exhibiting concentration-dependent dual biological activities

In this report, we describe the purification of a novel protease with dual biological actions from germ cell-conditioned medium (GCCM) where germ cells were isolated from adult rat testes using a mechanical procedure. Using multiple HPLC columns and two sequential high performance electrophoresis chromatography steps in association with an [125I]-collagen film assay to detect protease activity, a 41-kDa polypeptide (41-kDa-P) was purified to apparent homogeneity from GCCM. Partial N-terminal amino acid sequence analysis of the purified protein revealed a sequence of NH2-KYEFYEIXLL that, when compared with the existing database at Protein Identification Resource (PIR), GenBank, and BLAST revealed that this is a unique protein. The purified protein, when incubated with [125I]-testin, a Sertoli cell secretory product that is localized at the intertesticular cell junction and is resistant to tryptic digest, was found capable of hydrolyzing testin dose dependently. The proteolysis of [125I]-testin by this 41-kDa protein was inhibited by alpha2-macroglobulin (a Sertoli cell secretory product) also in a dose-dependent manner. A study on the interactions between different classes of protease inhibitors and the purified 41-kDa protein revealed that it is a serine protease. At doses ranging between 0.5 and 50 ng/ml, 41-kDa-P induced a dose-dependent inhibition of Sertoli cell secretory function using testin and clusterin as markers without any apparent proteolytic activity. However, at doses greater than 0.5 microg/ml, 41-kDa-P was found to cleave [125I]-collagen and [125I]-testin at physiological pH, indicating that this 41-kDa protein has dual biological activities whose primary action is concentration dependent. In view of the biological activities of this protease, it is postulated that this protein may be involved in facilitating germ cell migration in the epithelium.

Differential expression of multiple cathepsin mRNAs in the rat testis during maturation and following lonidamine induced tissue restructuring

In the seminiferous epithelium, germ cell development behind the blood-testis barrier involves continual degradation and renewal of inter-testicular cell junctions. This allows: (i) the translocation of developing germ cells from the basal lamina to the adluminal compartment during spermatogenesis, and (ii) the eventual release of mature spermatids into the tubular lumen during spermiation. Throughout spermatogenesis, cellular debris must also be removed from the epithelium Thus, it is conceivable that proteases, protease inhibitors, and cell junctional components are involved in these events. The present study sought to examine whether testicular cells can express multiple cathepsin mRNAs given that these proteases are involved in the degradation and processing of proteins as well as in tissue regeneration. By using total RNA isolated from primary cultures of Sertoli, Leydig, and germ cells for reverse-transcription and polymerase chain reaction (RT-PCR), the mRNAs of cathepsin B, C, D, H, L, and S were shown to be expressed by Sertoli and Leydig cells, whereas germ cells isolated from adult rats expressed all of the above cathepsin mRNAs except cathepsin D. Throughout postnatal development and maturation, the testicular steady-state mRNA levels of cathepsin B, C, D, L, and S remain relatively unchanged with the exception of cathepsin H whose mRNA level increased during maturation and peaked at 45-60 days of age. Using lonidamine, an anti-spermatogenic drug which is known to induce premature release of germ cells without affecting Leydig cell function by disrupting the inter-Sertoli-germ cell junctions, we have examined the differential expression of these cathepsin mRNAs in the testis at the time of extensive tissue restructuring. It was noted that the expression of cathepsin L and S in the testis increased significantly concomitant with the disappearance of elongate spermatids whereas the expression of cathepsin B, C, D, and H increased significantly when most of the round spermatids and spermatocytes were depleted. These results illustrate the intricate inter-relationship between these proteases in the testis during maturation and tissue restructuring.

Immunohistochemical localization of testin in the female reproductive system of the rat is consistent with its involvement in the turnover of specialized junctional complexes

The distribution of testin in the female reproductive system of rats throughout the estrous cycle was examined immunohistochemically. In ovarian follicles, immunostainable testin was localized at the junctions between adjacent granulosa cells. During follicular development, immunostainable testin surrounding the granulosa cells increased in every follicle but was reduced drastically when the follicle was undergoing atresia. Testin was also found in the junctions between adjacent germinal epithelial cells that covered the surface of the ovary, at the lower or the lower lateral borders of each cell. In the uterus and oviduct, immunostainable testin was detected only in the luminal and glandular epithelium, where it formed a polygonal network encircling the apical border of the epithelial cells. During the estrous cycle, there was no drastic change in the distribution of testin in the epithelial cells of the ovary. In the vaginal mucosa, testin was found to be localized only at the junction of the epithelial cells on the surface layer of the stratified epithelium; at different stages of the estrous cycle, distinctive staining for testin could be found at proestrus, metestrus, and diestrus, but not at estrus. It is postulated that testin is a cell junction-associated protein in the female reproductive system.

Astrocytes cultured in vitro produce estradiol-17beta and express aromatase cytochrome P-450 (P-450 AROM) mRNA

Aromatase cytochrome P-450 (P-450AROM) is an enzyme that catalyzes the conversion of androgen to estrogen. Estrogen plays an important role in the neuronal function by promoting the formation of dendrites and may be involved in protecting the neurons in the cerebral cortex against specific pathological conditions such as Alzheimer's disease. However, the cellular origin of estrogen in the brain is not known. The present study demonstrated for the first time the production of estradiol-17beta and expression of P-450AROM mRNA in astrocytes isolated from the cerebral cortex of neonatal rats. Immunocytochemical studies using a monospecific antibody against rat P-450AROM has shown that this enzyme was localized in the cytoplasm of astrocytes. Interleukin-1 (IL-1) has been shown to stimulate the proliferation and differentiation of astrocytes and to affect the aromatase activity in non-neuronal cells such as Sertoli, Leydig, and placental cells. Treatment of astrocytes with IL-1beta induced a dose-dependent inhibition of estradiol production. This inhibitory action of IL-1beta can be reversed by the addition of anti-IL-1beta antibody. Since astrocytes are involved in the synaptic reorganization in the brain by removing cellular debris and by providing the necessary biological factors for neuronal growth, the ability of astrocytes to produce estradiol-17beta and express P-450AROM mRNA in vitro suggests a new role for these cells in protecting and supporting neurons.

Testin is tightly associated with testicular cell membrane upon its secretion by sertoli cells whose steady-state mRNA level in the testis correlates with the turnover and integrity of inter-testicular cell junctions

Testin, a Sertoli cell secretory protein whose mRNA is predominantly expressed in the testis, was shown to become tightly associated with Sertoli cell membrane upon its secretion whose solubilization requires the use of a detergent such as SDS. In the in vitro studies using Sertoli cells cultured at high cell density, where specialized junctions were being formed, the concentration of "soluble" testin in the spent media was greatly reduced versus monolayer cultures at low cell density, where specialized junctions were absent. Conversely, the concentration of "membrane-bound" testin from detergent-solubilized Sertoli cell membrane extract was positively correlated to the existence of specialized junctions in these cultures. In normal rat testes, the level of radioimmunoassayable soluble testin in the cytosol was low. However, when the inter-testicular cell junctions were disrupted either by a drug treatment such as lonidamine in vivo or by a physical treatment in vitro such as exposing Sertoli-germ cell co-cultures where specialized junctions were formed to a hypotonic treatment, a drastic surge in the testin gene expression was noted. Thus, testin can become tightly associated with Sertoli cell membrane upon its secretion when intercellular junctions are formed. It is also a marker to monitor the integrity of inter-testicular cell junctions.

Effect of clozapine on dopamine-induced inhibition of prolactin release from cultured rat pituitary cells

Although the atypical antipsychotic agent clozapine has little propensity to induce hyperprolactinemia in humans it increases serum prolactin levels in the rat. In this study, the effects of clozapine and of some typical antipsychotic drugs on basal and dopamine-mediated prolactin secretion from cultured rat pituitary cells were compared. Despite being less potent than the other antipsychotic agents tested, clozapine reverted the effect of dopamine on prolactin secretion in vitro. This finding suggests that clozapine interferes with dopamine receptors in the pituitary gland.

The role of vasopressin on the effect of U-50,488 to block the development of morphine tolerance and physical dependence

U-50,488, a selective kappa-opioid receptor agonist, has been reported to inhibit the development of antinociceptive tolerance to morphine in mice, rats and guinea pigs, but the mechanism involved in this action remains unknown. Since U-50,488 has been reported to suppress the plasma vasopressin level, we investigated the role of vasopressin with U-50,488 in the male Sprague Dawley rat in this study. Animals (230-270 g) were chronically treated with morphine (10 mg/kg, i.p.) twice a day for 6 days in order to induce tolerance to antinociceptive effect measured by tail-flick test. Withdrawal symptoms were precipitated by naloxone (10 mg/kg, i.p.) on day 7. U-50,488 (i.p.) or AVP (i.p. or i.c.v.) or U-50,488 and AVP was (were) coadministered with chronic morphine to investigate their effects on morphine tolerance and dependence. We found that coadministration of 8 mg/kg U-50,488 (i.p.) with morphine almost completely block morphine tolerance and partially block withdrawal symptoms. In contrast, coadministration of AVP (0.3 microgram/kg, i.p., or 0.01 microgram, i.c.v.) with morphine and U-50,488, the effects of U-50,488 to block morphine tolerance and dependence were reversed. In addition, treatment of AVP antagonist (dPTyr(Me)AVP, 0.5 microgram/kg, i.p. or 0.5 microgram, i.c.v.) has the similar effect as U-50,488 to block morphine tolerance. In summary, the effect of U-50,488 to block morphine tolerance and dependence may relate to its inhibitory effect on AVP release.

Purification and cellular localization of beta2-microglobulin in the testis

Using multiple high performance liquid chromatography (HPLC) steps, a protein of 12 kDa was purified to apparent homogeneity from rat Sertoli cell-enriched culture medium (SCCM). Partial N-terminal amino acid sequence analysis revealed a sequence of NH2-IQKTPQIQVYS which is identical to beta2-microglobulin (beta2MG) previously identified in the brain. Studies by sequential reverse transcription and polymerase chain reaction (RT-PCR) indicated that beta2MG mRNA was expressed in Sertoli but not in germ cells suggesting that Sertoli cells are the source of this protein in the seminiferous epithelium behind the blood-testis barrier. The steady-state beta2MG mRNA level in Sertoli cells cultured in vitro was not affected by either follicle stimulating hormone (FSH), testosterone, estradiol, dexamethasone or several cytokines such as interleukin-1beta (IL-1beta), interleukin 6 (IL-6), and transforming growth factor beta (TGF-beta), with the exception of interferon-gamma (INFgamma) which induced a dose-dependent stimulation of beta2MG mRNA. The possible physiological significance of this protein in the male reproductive tract is discussed.

Ability of trypsin in mimicking germ cell factors that affect Sertoli cell secretory function

A biological factor that inhibits the in vitro secretion of testin by Sertoli cells was purified to apparent homogeneity from conditioned medium of germ cells isolated using trypsin. Partial N-terminal amino acid sequence analysis of the purified germ cell factor revealed a sequence of NH2-IVGGYTXAAN. Comparison of the sequence with the existing protein database revealed that it is homologous to trypsin. Immunoprecipitation experiments using either [35S]-labeled germ or Sertoli cell proteins and a monospecific anti-trypsin antibody failed to demonstrate the synthesis and secretion of trypsin by these testicular cells, suggesting the isolated factor is the residuary trypsin that was used for isolating germ cells from seminiferous tubules. Subsequent experiments revealed that trypsin per se can inhibit the secretion of Sertoli cell testin and clusterin dose-dependently, whose effect can be prohibited by soybean trypsin inhibitor (STI). In view of these findings, a nonenzymatic procedure was deemed necessary to prepare germ cell conditioned medium (GCCM) to assess whether an authentic biological factor(s) is indeed present. Four batches of conditioned medium of germ cells isolated by a mechanical procedure without the use of trypsin were fractionated by sequential Mono Q anion exchange and C8 reversed-phase HPLC. When these fractions were monitored for testin modulatory activity using an in vitro bioassay with primary cultures of Sertoli cells, it was shown that GCCM prepared by this procedure indeed contained testin modulatory bioactivity. Since testin is a novel component of specialized junctions between Sertoli and germ cells, the identification of a germ cell factor(s) that affects its secretion by Sertoli cells suggests a dynamic biochemical relationship between these cell types in the seminiferous epithelium.

Treatment of the femoral neck amd trochanteric benign lesions

Thirty-five patients with a benign lesion of the femoral neck or trochanter were treated and seen in followup at the authors' institution from 1988 to 1991. Sixteen men and 19 women between the ages of 18 and 54 years (average, 27 years) were seen at an average followup of 3 years 6 months (range, 2-5 years). Eight patients had aneurysmal bone cyst; 14 had monostotic fibrous dysplasias; 2 had giant cell tumors; and 11 had simple bone cysts. Eleven patients had pathologic fractures. All patients were treated with curettage and bone grafting in conjunction with a sliding hip compression screw and plate. The bone grafting included a combination of a deep frozen allogenic cortical strut with autogenous iliac cancellous bone to fill the remaining defect space after lag screw and cortical strut had been implanted. At followup, all patients had good bony healing and incorporation of the implanted graft. There were no complications and no local recurrences. All of the functional results were excellent.

Purification, cDNA cloning, and developmental changes in the steady-state mRNA level of rat testicular tissue inhibitor of metalloproteases-2 (TIMP-2)

Using multiple high-performance liquid chromatography (HPLC) steps and high-performance electrophoresis chromatography (HPEC) in conjunction with an [125I]collagen film assay to identify inhibitors of metalloproteases, we have purified a 22-kDa polypeptide to apparent homogeneity from primary Sertoli cell-enriched culture medium. Partial N-terminal amino acid sequence analysis revealed that this protein is similar to the human tissue inhibitor of metalloproteases-2 (TIMP-2). To determine the similarity of rat testicular TIMP-2 to the human homolog, a full-length cDNA coding for rat testicular TIMP-2 was isolated from a rat Sertoli cell cDNA expression library and sequenced. Analysis of the nucleotide sequence and the deduced amino acid sequence of the rat testicular TIMP-2 cDNA revealed an 84 and 98% homology with the human TIMP-2 nucleotide and amino acid sequences, respectively. A survey of its mRNA transcripts in different tissues by northern blots revealed the presence of two mRNA species of 3.7 and 1.3 kb in the testis and brain but not in the kidney, spleen, epididymis, and liver in adult male rats. Studies using polymerase chain reaction (PCR) and Southern blot to detect the TIMP-2 mRNA using total RNA isolated from germ cells, Sertoli cells, and Leydig cells have shown that only Sertoli and Leydig cells expressed TIMP-2 mRNA. These results indicate that Sertoli cells are the major source of TIMP-2 in the testis behind the blood-testis barrier (seminiferous tubule barrier). During testicular development from 3 to 60 days of age, the testicular steady-state TIMP-2 mRNA level increased steadily with an advancement of age. Such an increase in the steady-state testicular TIMP-2 mRNA level apparently is not the result of an up-regulation by germ cells because germ cells cocultured with Sertoli cells failed to elicit an increase in the Sertoli cell steady-state TIMP-2 mRNA level. The results of this study suggest that TIMP-2 secreted by Sertoli cells may play a role in tissue restructuring and germ cell migration during spermatogenesis.

Intestinal absorption studies on peptide mimetic alpha-methyldopa prodrugs

Two dipeptide mimetic prodrugs, 1 and 2, and two tripeptide mimetic prodrugs, 3 and 4, of L-alpha-methyldopa were evaluated for intestinal absorption by in-situ single pass rat jejunal perfusion studies and by in-vitro uptake experiments in brush-border membrane vesicles (BBMVs) prepared from rat intestine. In the perfusion studies, compound 1 demonstrated a 3.5-fold increase in permeability (Pm* = 2.27) as compared with that of alpha-methyldopa (Pm* = 0.65), indicating that this prodrug was better absorbed in the intestine than its parent drug. Other prodrugs showed no significant improvement in intestinal permeability. The results correlated with the results of BBMV uptake studies. In the presence of an inward proton gradient, compound 1 showed Michaelis-Menton saturable kinetics of BBMV uptake with a low value of K(m) (0.06 +/- 0.13 mM) and a high value of Vmax/K(m)(36.38 nmol (mg protein)-1/30s mM-1) at a low concentration range and a linear uptake at high concentrations with Kd = 0.14 +/- 0.02 mM. Compounds 2 and 3 were mainly taken up in BBMVs via passive diffusion. Compound 4 was taken up in BBMVs basically via the carrier-mediated transport system, while the rate of uptake was much lower than that of compound 1. The uptake of compounds 1 and 4 was significantly inhibited by dipeptides L-Gly-L-Pro and L-Gly-L-Phe, and cephradine, a beta-lactam known to be transported via the dipeptide carrier system, indicating that both compounds were taken up in BBMVs via the H(+)-coupled dipeptide-mediated transport system. In contrast to the complicated uptake profile of alpha-methyldopa, the higher rate of BBMV uptake with less variation demonstrated on compound 1 suggested that the attached nonessential amino acid moiety, D-phenylglycine, is a feasible delivery tool in carrying the parent drug through the intestine.

Astrocytes synthesize and secrete prostaglandin D synthetase in vitro

Prostaglandin D synthetase [PGD-S, prostaglandin-H2 D-isomerase, (5Z, 13E)-(15S)-9alpha, 11 alpha-epidioxy-15-hyrdroxyprosta-5,13-dienoate D-isomerase, EC 5,3,99,2], an enzyme that catalyzes the formation of prostaglandin D2, was originally isolated from homogenates of rat brain and spleen and is known to be a membrane-bound enzyme. Subsequent immunohistochemical studies have shown that PGD-S is associated with neurons in the brain of immature rats, whereas in adult rats it is associated with oligodendrocytes. Several recent studies have shown that the beta-trace protein isolated from human cerebrospinal fluid (CSF), the second most abundant protein in human CSF after albumin, is equivalent to PGD-S. In this paper, we report the preparation of a monospecific polyclonal antibody against purified PGD-S isolated from human CSF and the establishment of a specific radioimmunoassay for this protein. Using this radioimmunoassay in conjunction with immunoblot analysis, PGD-S was detected in various biological fluids including serum, aqueous humor, and rete testis fluid. In addition, an antibody prepared against human PGD-S partially cross-reacted with the PGD-S in the rat and ram. Using a monospecific polyclonal antibody prepared against purified rat PGD-S isolated from rat CSF in conjunction with [35S]methionine incorporation and immunoprecipitation techniques, it was shown for the first time that PGD-S is actively synthesized and secreted by astrocytes cultured in vitro, suggesting the astrocyte is the cellular origin of PGD-S in the CSF. The identification of the astrocyte as the cellular origin of this unique enzyme will allow the use of an in vitro system to study its regulation.

N-cubylmethyl substituted morphinoids as novel narcotic antagonists

N-Cubylmethylnormorphine (1) and N-cubylmethylnoroxymorphone (2) have been synthesized and found to be more potent ligands at the mu and kappa opioid receptors than morphine and oxymorphone respectively. In the guinea-pig ileum preparation, compounds 1 and 2 were characterized as opioid mu antagonists (Ke = 68 and 16 nM, respectively). Compound 2 also showed effective kappa-antagonism (Ke = 22 nM). The narcotic antagonism activity of 1 has been confirmed by in vivo assays.

Transforming prenatal care: reflections on the past and present with implications for the future

The current model for delivery of prenatal care was developed more than 100 years ago. Evidence suggests that this model is no longer appropriate for meeting national health objectives or for meeting the needs of a diverse population of pregnant women. This article provides a historical overview of prenatal care; describes the current system for care delivery and problems associated with it; and suggests strategies for transforming care into an effective, comprehensive model.

Hepatocellular carcinoma with metastasis to right atrium--a report of three cases

Hepatocellular carcinoma (HCC) is one of the most common neoplasma in Taiwan. The tumor itself has the tendency of extension into the venous system, such as to the portal vein, hepatic vein and inferior vena cava (IVC), but intra-atrial metastasis is unusual. Antemortem diagnosis was difficult before the availability of two-dimensional echocardiography (2-DE). Sometimes, the first symptoms and signs are cardiogenic manifestations such as dyspnea on exertion, syncope, edema of the lower legs, and shock. Clinicians may mistakenly make the wrong diagnosis of heart failure. Because of this, we hereby report three cases of HCC with right intra-atrial metastasis to raise the physician's awareness. All three cases initially presented as right side heart failure. Imaging study revealed hepatocellular carcinoma with right intra-atrial metastasis. Two of the three cases died within one month after diagnosis.

Purification of a candidate gonadotropin surge inhibiting factor from porcine follicular fluid

Several lines of evidence suggest that the ovaries of many species produce a nonsteroidal substance, termed gonadotropin surge inhibiting factor (GnSIF), which inhibits the midcycle gonadotropin surge and attenuates the pituitary response to endogenous or exogenous GnRH. We have previously reported the partial purification of GnSIF from porcine follicular fluid (pFF) and its differentiation from inhibin. We present now the purification of GnSIF to homogeneity and determination of the partial NH2-terminal amino acid sequence. The bioassay for GnSIF used rat pituitary cells in short-term culture that were incubated with test fractions for 48 h, washed, and then incubated with 10 nM GnRH plus test fractions for 4 h. GnSIF activity is defined as the suppression of GnRH-stimulated LH secretion. GnSIF was purified from 500 ml of pFF using sequential heparin-Sepharose, anion-exchange, and cation-exchange liquid chromatography followed by gel permeation, hydrophobic interaction, and mono-Q HPLC steps. Using these six purification steps, we have obtained an apparently homogenous preparation that stains as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. GnSIF has an apparent mol wt of 69K. Limited NH2-terminal sequence analysis reveals that GnSIF has no sequence homology with other reproductive hormones including the inhibins, activins, and follistatins. Over the dose range tested, GnSIF had no effect on basal LH or FSH secretion by pituitary cells in culture and only slightly inhibited GnRH-stimulated FSH secretion at the highest dose tested. In addition, there was no inhibin or follistatin immunoactivity in the GnSIF preparation. As such, GnSIF appears to be a novel protein in pFF that inhibits GnRH-stimulated LH secretion, and which may participate along with other ovarian proteins and steroids in the regulation of pituitary gonadotropin secretion.

Rat testin is a newly identified component of the junctional complexes in various tissues whose mRNA is predominantly expressed in the testis and ovary

Testin I and testin II are the two molecular variants of testin that are synthesized and secreted by Sertoli cells in vitro. N-Terminal and partial internal amino acid sequence analysis of testin I and testin II reveals that these molecules are identical with the exception that testin II has three extra N-terminal amino acids of TAP compared to testin I. Studies using immunohistochemistry suggested that testin is a component of the specialized junctional complexes in the seminiferous epithelium and other tissues. Immunoreactive testin is localized not only at Sertoli-Sertoli and Sertoli-germ cell junctions, but also at sites of similar junctions in the liver, epididymis, kidney, and intestine. Other physiological studies have shown that the secretion of testin is tightly coupled to the presence of germ cells. In view of its possible role in germ cell development and its unique localization in the cell junction, the purpose of the present study was to determine the structure of testin by sequencing its full-length cDNA. Two synthetic degenerate oligonucleotides based on the N-terminal and an internal amino acid sequence were used for polymerase chain reaction (PCR) to obtain a 289-bp cDNA fragment. This PCR product was subsequently used to isolate a 1371-bp cDNA from a cDNA expression library constructed from Sertoli cell poly(A) RNA. This cDNA coded for a 333 amino acid peptide that starts with an ATG initiation codon from the 5' end and ends with a TGA termination codon located 245 nucleotides before the polyadenylation site. The deduced amino acid sequence indicates that testin contains a 16 amino acid signal peptide with two possible cleavage sites that yield 314 and 317 amino acids for testin I and testin II with calculated molecular weights of 36,029 and 36,299, respectively. Comparison of the entire coding region of testin with existing sequences at Genbank, EMBL, and Protein Identification Resource indicates that testin shares 58%, 57.4%, and 61% identity with rat, mouse, and human cathepsin L at the amino acid level, respectively. The positions of all of the 7 Cys residues and 8 of the 10 Trp residues in testin are conserved with respect to those present in cathepsin L. It is noted that Cys-122 in the predicted active site of cathepsin L was replaced with Ser-122 in testin. In view of the striking primary sequence homology between testin and cathepsin L, we assayed the proteolytic activity of testin using conditions known to activate cathepsin L.(ABSTRACT TRUNCATED AT 400 WORDS)

Cerebrin-50, a human cerebrospinal fluid protein whose mRNA is present in multiple tissues but predominantly expressed in the lymphoblastoid cells and the brain

A full-length cDNA of 2295 bp coding for a human cerebrospinal fluid protein, designated cerebrin-50, has been isolated from a human brain cDNA expression library. Nucleotide sequence analysis of this cDNA revealed that it codes for a 435 amino acid polypeptide which starts with an ATG initiation codon from the 5'-end and ends with a TGA termination codon with a calculated molecular weight of 51,484 daltons. A 10-amino acid peptide of NH2-SGDLETRYWG based on the deduced amino acid sequence of the cerebrin-50 cDNA was synthesized, conjugated to bovine serum albumin and was used to raise a monospecific polyclonal antibody in a rabbit. Immunoblot analysis using this antibody indicated the presence of a 52 kD protein in the human cerebrospinal fluid, brain cytosol, T lymphoblastoid cell-conditioned medium, and human serum; it is also noted that the concentration of this 52 kD protein is several order of magnitude higher in the cerebrospinal fluid than in other biological fluids. The presence of its mRNA in the brain, T lymphoblastoid cells, spleen, liver, and testis was confirmed by sequential use of reverse-transcription and polymerase chain reaction (RT-PCR). Preliminary analysis by quantitative RT-PCR has noted that the expression of the cerebrin-50 mRNA is higher in the lymphoblastoid cells and brain than the spleen, liver, and testis.