[Study on diarrhea disease and Escherichia coli strains harboring HPI pathogenicity island of Yersinia enterolitica in Shandong province]

OBJECTIVE

It was found that some E. coli strains previously identified as entero SLTs-producing and invasive E. coli (ESIEC), harboring HPI pathogenicity island of Yersinia enterolitica. This research was designed to reveal prevalence, susceptible group and clinical features it caused.

METHODS

All of the diarrhea patients were from the out-patient units of four hospitals in Shandong province from June to November of 1997. Stool specimen were collected before administration of antibiotics for isolation of enteric bacterial pathogen. Clinical symptoms were recorded at the same time.

RESULTS

A total number of 449 enteric pathogenic bacteria strains were detected among stool samples from 671 patients, with isolation rates of Shigella species and diarrheagenic E. coli 25.48% and 15.05% respectively. When irp-2 and ipaB gene fragments were used as DNA probes, 42 of 176 un-identifiable strains were found irp-2(+) and ipaB(-), which were identified as HPI-harboring E. coli. Typical symptoms of the diarrhea caused by HPI-harboring E. coli were described as mild, including abdominal pain, shiver and vapidity. Temperature of the patients was usually normal. Over 6 times of bowel movements per day was frequently observed, of which most were unformed stools with mucous.

CONCLUSION

HIP-harboring E. coli was an important diarrheagenic pathogen identified from 671 patients with diarrhea. Shigella was found to be the majority strain.

Platelet monoamine oxidase B and plasma beta-phenylethylamine in Parkinson's disease

OBJECTIVE

To evaluate the correlation between changes in platelet monoamine oxidase type B (MAO-B) activity and plasma beta-phenylethylamine (PEA) concentrations in patients with Parkinson's disease and controls.

METHODS

Platelet MAO-B activity and plasma PEA were measured with gas chromatography-mass spectrometry (GC-MS) in patients with Parkinson's disease treated with levodopa (12 men and 12 women) or selegiline (three men and three women), and physically healthy subjects as a control group (10 men and 10 women).

RESULTS

Platelet MAO-B activity was significantly higher in the Parkinson's disease group (mean 542 (SD 318) pmol/10(7) platelets/30 min) than in the control group (mean 349 (SD 307) pmol/10(7) platelets/30 min) (p<0.05). By contrast, the plasma PEA concentrations in patients with Parkinson's disease were significantly lower than in the control group (mean 532 (SD 243) pg/ml; 931 (SD 560) pg/ml) (p<0.01). The plasma PEA concentrations in patients with Parkinson's disease treated with selegiline were prominently higher than in patients with no selegiline treatment (p<0.001). There was a significantly negative correlation between platelet MAO-B activity and plasma PEA concentrations in patients (n=24, r=-0.466, p<0.001).

CONCLUSIONS

The increase in platelet MAO-B activity and decrease in plasma PEA concentrations in patients with Parkinson's disease may be involved in the pathophysiological processes of the disease, and these changes are reversed by treatment with selegiline.

[Analysis on ecophysiological characteristics of leaf photosynthesis of Aneurolepidium chinense in songnen grassland]

A series of physiological characteristics of leaf photosynthesis and environmental factors are measured on Aneurolepidium chinense in Songnen salinized grassland during the growth season. The results showed that the daily change pattern of net photosynthetic rate (Pn) of Aneurolepidium chinense could be expressed as a two-humped curve, the daily change pattern of transpiration rate is one-humped curve. In addition, net photosynthetic rate (Pn), transpiration rate (E) and stomatal resistance (Rs) are affected by various environmental factors. At different growth stage, the influence of environmental factor on them is different, and even the same environmental factor had an different effect on Pn, E and Rs. In the whole growth period, photosynthetic available radiation (PAR) was the most intensive effect on the photosynthesis of Aneurolepidium chinense. Among Pn, E and Rs, E was one of the most obvious ecophysiological factor affected by environmental factors.

Genetic dissection of the olfactory bulbs of mice: QTLs on four chromosomes modulate bulb size

Olfaction is influenced by a complex mix of environmental and genetic factors that modulate the production, migration, and maturation of cells in the olfactory bulbs. In this study we analyzed effects of sex, age, body weight, and brain weight on olfactory bulb size in sexually mature mice. We then used regression corrected values (residuals) to map quantitative trait loci (QTLs) that selectively modulate bulb weight. This biometric analysis has relied on an F2 intercross between C57BL/6J (B6) and DBA/2J (D2) inbred strains and a large sample of 35 BXD recombinant inbred (RI) strains. Bilateral bulb weight in adult mice ranges from 10 to 30 mg. Half of this remarkable variation can be predicted from differences in brain weight, sex, body weight, and age. A 100-mg difference in brain weight is associated with a 4.4-mg difference in bulb weight. Bulbs gain in weight by 0.2 mg/week--a 1% increase that continues until at least 300 days of age. Males tend to have slightly larger bulbs than females. By combining data from both related crosses (F2 and RI) we identified four QTLs with selective effects on bulb size (genomewide p < .05). Bulb4a is located on chromosome 4 (Chr 4) and Bulb6a is located on Chr 6. Alleles inherited from B6 at both of these loci increase bulb weight by 0.5-1.0 mg. Bulb11a is located on proximal Chr 11 and Bulb17a is located on the proximal part of Chr 17. In contrast to the first two QTLs, B6 alleles at these two loci decrease bulb weight by 0.5-1.0 mg. Collectively, the four loci account for 20% of the phenotypic variance in bulb weight.

Development of a fungus-specific PCR assay for detecting low-level fungi in an indoor environment

A fungus-specific PCR assay using only one primer set has been developed for detecting indoor fungi. Four fungal primer sets, NS3/NS4, NS5/NS6, FF1/FR1 and FF2/FR1, were tested with DNA from humans, rats, mice, bacteria, pollens and six commonly found fungal species (Alternaria chamydospora, Aspergillus flavus, Candida famata, Cladosporium fermentans, Penicillium chrycoIgenum and Stachybotrys chartarum). Results indicated that, although all four primer sets could amplify the fungal DNA, only FF2/FR1 demonstrated no cross-amplification with non-fungal DNA. In addition, these amplified fragments were sequenced to ensure that they indeed matched known fungal DNA sequences. Furthermore, besides the tested fungi, eighteen more genera of fungal sequences were examined and found to match the FF2/FR1. Here, the method of bead-beating was identified as the most effective way for spore breakage and fungal DNA release. The PCR amplification efficiency and potential inhibition were examined using different process solutions and preparation procedures. It was found that, when using 20% nutrient media and homogenization-first procedure, a higher amplification efficiency with less inhibition was achieved. Although positive bands were observed at 0.2 fungal spore/reaction using the homogenization-first procedure, the sensitivity of this assay would be two fungal spores/reaction for environmental samples.

Interleukin-12 induces gene expression in interleukin-2 stimulated human T lymphocytes

IL-12 is a critical immunoregulatory cytokine that promotes cell-mediated immune responses by inducing the differentiation of Th1 cells. To better clarify the molecular basis of IL-12 action, we compared the gene expression in human T lymphocytes activated by IL-2 and IL-12. mRNAs from T lymphocytes activated by either IL-2 alone or IL-2 plus IL-12 were transcribed into cDNAs. A differential mRNA display was conducted. As a result, differential display of five cDNA fragments was obtained. Sequence analysis suggests that they had high homology with recorded genes as found by a computer search against GenBank. Two full genes of the five fragments were cloned, which activation-induced C-type lectin and glucose transporter-like protein. Interestingly, these proteins were expressed in the T cells stimulated by IL-2 and IL-12, but not in the T cells stimulated by IL-2 alone. These results suggest that C-type lectin and glucose transporter-like protein may play an important role in the T lymphocyte activation induced by IL-12.

[Dynamic changes of respiration pathway and active oxygen levels in subcultured tobacco callus]

During the growth and senescence of tobacco callus, the total respiration rate showed two peaks on the 11th and 19th day, respectively. The development and operation of alternative pathway increased gradually, reached the maximum between two respiration peaks, and then declined in the following days, but the cytochrome pathway was still as a main electron transport pathway consistently. Analysis on the levels of active oxygen species during the growth and senescence process in tobacco callus suggested that H2O2 and O2.- were involved in some way in the induction of the development and operation of the alternative pathway, but the increase of production rate of OH might suppress both the development and operation of the alternative pathway, which were enhanced by H2O2 and O2.- respectively. These results were further proved by the use of active oxygen scavengers. The possible participation of the alternative pathway enhanced by active oxygen in the initial senescence process was discussed.

[Dynamics of respiration pathway in transgenic salt-tolerant wheat and its receptor under salt stress]

Using transgenic salt-tolerant wheat 89122 and its receptor Longchun 13 as test material, the dynamic changes of respiration pathway of wheat seedlings at different salt concentration were studied. The appearance of salt respiration was later in 89122 than in Longchun 13. The changes of Valt and rho Valt of both varieties had different patterns during salt stress process. Valt was suppressed by high salt levels, but could be induced by low salt levels in Longchun 13. The rho Valt and rho' Vcyt of two varieties were cooperatively regulated with each other to adapt to salt stress, and rho' Vcyt was the main electron transport pathway. The possible physiological roles of cyanide-resistant respiration were also discussed. It was suggested that the operation intensity of cyanide-resistant respiration could serve as a physiological index of plant salt-tolerance.

[Effect of combined treatment of 60Co gamma-ray and EMS on antioxidase activity and ODAP content in Lathyrus sativus]

Lathyrus sativus seeds were treated with 60Co gamma-ray and EMS(ethyl methane sulfonate), and their emergence rate and SOD, POD and CAT activities were determined. The result indicated that the treatment decreased the emergence rate. The activities of SOD and POD were changed in accordance with the increase of irradiation dose and EMS concentration, while that of CAT had no obvious change. After treatment, the ODAP content in Lathyrus sativus decreased. Amutant was developed, with toxin content of 0.1%, compared to 0.2% in control.

Glycoprotein D or J delivered in trans blocks apoptosis in SK-N-SH cells induced by a herpes simplex virus 1 mutant lacking intact genes expressing both glycoproteins

We have made two stocks of a herpes simplex virus 1 mutant lacking intact U(S)5 and U(S)6 open reading frames encoding glycoproteins J (gJ) and D (gD), respectively. The stock designated gD(-/+), made in cells carrying U(S)6 and expressing gD, was capable of productively infecting cells, whereas the stock designated gD(-/-), made in cells lacking viral DNA sequences, was known to attach but not initiate infection. We report the following. (i) Both stocks of virus induced apoptosis in SK-N-SH cells. Thus, annexin V binding to cell surfaces was detected as early as 8 h after infection. (ii) U(S)5 or U(S)6 cloned into the baculovirus under the human cytomegalovirus immediate-early promoter was expressed in SK-N-SH cells and blocked apoptosis in cells infected with either gD(-/+) or gD(-/-) virus, whereas glycoprotein B, infected cell protein 22, or the wild-type baculovirus did not block apoptosis. (iii) In SK-N-SH cells, internalized, partially degraded virus particles were detected at 30 min after exposure to gD(-/-) virus but not at later intervals. (iv) Concurrent infection of cells with baculoviruses did not alter the failure of gD(-/-) virus from expressing its genes or, conversely, the expression of viral genes by gD(-/+) virus. These results underscore the capacity of herpes simplex virus to initiate the apoptotic cascade in the absence of de novo protein synthesis and indicate that both gD and gJ independently, and most likely at different stages in the reproductive cycle, play a key role in blocking the apoptotic cascade leading to cell death.

Expression, purification, and characterization of gp160e, the soluble, trimeric ectodomain of the simian immunodeficiency virus envelope glycoprotein, gp160

The envelope glycoprotein, gp160, of simian immunodeficiency virus (SIV) shares approximately 25% sequence identity with gp160 from the human immunodeficiency virus, type I, indicating a close structural similarity. As a result of binding to cell surface CD4 and co-receptor (e.g. CCR5 and CXCR4), both SIV and human immunodeficiency virus gp160 mediate viral entry by membrane fusion. We report here the characterization of gp160e, the soluble ectodomain of SIV gp160. The ectodomain has been expressed in both insect cells and Chinese hamster ovary (CHO)-Lec3.2.8.1 cells, deficient in enzymes necessary for synthesizing complex oligosaccharides. Both the primary and a secondary proteolytic cleavage sites between the gp120 and gp41 subunits of gp160 were mutated to prevent cleavage and shedding of gp120. The purified, soluble glycoprotein is shown to be trimeric by chemical cross-linking, gel filtration chromatography, and analytical ultracentrifugation. It forms soluble, tight complexes with soluble CD4 and a number of Fab fragments from neutralizing monoclonal antibodies. Soluble complexes were also produced of enzymatically deglycosylated gp160e and of gp160e variants with deletions in the variable segments.

The performance and design of ultrasonic vibration system for flexural mode

The matrix method for analyzing flexural vibration system is outlined. The displacement, stress and velocity gain of ultrasonic flexural vibration systems are investigated by transfer matrix method. A design method is given for flexural transducer and vibration system.

Transgenic plants expressing cationic peptide chimeras exhibit broad-spectrum resistance to phytopathogens

Here we describe a strategy for engineering transgenic plants with broad-spectrum resistance to bacterial and fungal phytopathogens. We expressed a synthetic gene encoding a N terminus-modified, cecropin-melittin cationic peptide chimera (MsrA1), with broad-spectrum antimicrobial activity. The synthetic gene was introduced into two potato (Solanum tuberosum L.) cultivars, Desiree and Russet Burbank, stable incorporation was confirmed by PCR and DNA sequencing, and expression confirmed by reverse transcription (RT)-PCR and recovery of the biologically active peptide. The morphology and yield of transgenic Desiree plants and tubers was unaffected. Highly stringent challenges with bacterial or fungal phytopathogens demonstrated powerful resistance. Tubers retained their resistance to infectious challenge for more than a year, and did not appear to be harmful when fed to mice. Expression of msrA1 in the cultivar Russet Burbank caused a striking lesion-mimic phenotype during leaf and tuber development, indicating its utility may be cultivar specific. Given the ubiquity of antimicrobial cationic peptides as well as their inherent capacity for recombinant and combinatorial variants, this approach may potentially be used to engineer a range of disease-resistant plants.

Diphenyl sulfoxides as selective antagonists of the muscarinic M2 receptor

Structure activity studies on [4-(phenylsulfonyl)phenyl]methylpiperazine led to the discovery of 4-cyclohexyl-alpha-[4-[[4-methoxyphenyl(S)-sufinyl]phenyl]-1-pi perazineacetonitrile, 1, an M2 selective muscarinic antagonist. Affinity at the cloned human M2 receptor was 2.7 nM; the M1/M2 selectivity is 40-fold.

[Accumulation of ABA and ODAP in Lathyrus sativus under water stress]

The roots of fifteen days old Lathyrus sativus seedlings were treated by PEG, PEG + ABA and ABA, and their leaves were sampled to determine the contents of endogenic ABA, ODAP, MDA and H2O2 and the activity of superoxide dismutase, catalase, peroxidase and glutathione reductase. The results showed that after treated, the contents of ABA and ODAP in leaves increased markedly. The addition of exogenous ABA decreased the increment of MDA and H2O2 contents and retarded the attenuation of CAT activity, which were induced by PEG stress, and enhanced the GR activity. In addition, when materials were treated with exogenous ABA in a long time, the ABA content in leaves was increased markedly, and ODAP was then accumulated. There was no significant effect on metabolism of active oxygen in the early days(0-3 days) of ABA treatment, but the activities of SOD, POD, CAT and GR decreased, and the contents of MDA and H2O2 increased in leaves of Lathyrus sativus with the duration of ABA treatment(7-15 days). The results indicated that ABA could promote the accumulation of ODAP in leaves of Lathyrus sativus.

Wild-type herpes simplex virus 1 blocks programmed cell death and release of cytochrome c but not the translocation of mitochondrial apoptosis-inducing factor to the nuclei of human embryonic lung fibroblasts

Programmed cell death activated by herpes simplex virus 1 mutants can be caspase dependent or independent depending on the nature of the infected cell. The recently discovered mitochondrial apoptosis-inducing factor (AIF) on activation is translocated to the nucleus and induces programmed cell death that is caspase independent. To assess the role of AIF and also to assay apoptosis-related events in primary human embryonic lung (HEL) fibroblasts, cells were mock infected or infected with wild-type virus previously shown not to induce apoptosis in continuous lines of primate cells or with the d120 mutant lacking infected cell protein no. 4 (ICP4) and were shown to induce apoptosis in all cell lines tested. Cells exposed to dexamethasone or osmotic shock induced by sorbitol were the positive controls. The results were as follows: (i) AIF was translocated to the nucleus in all infected cell cultures and in cells treated with dexamethasone or sorbitol, but cells infected with the wild type-virus showed no evidence of undergoing programmed death. (ii) Cytochrome c was released from mitochondria of cells infected with the d120 mutant or exposed to dexamethasone or sorbitol but not from mitochondria in cells treated with sorbitol and infected with the wild-type virus. (iii) Poly(ADP-ribose) polymerase was cleaved in mock-infected cells exposed to sorbitol or dexamethasone and in cells infected with the d120 mutant but not in either untreated cells infected with wild-type virus or cells exposed to sorbitol and then infected with wild-type virus. In contrast to HEp-2 cells, neither d120 infection nor treatment with dexamethasone or sorbitol caused fragmentation of DNA in HEL fibroblasts. Electron microscopic examination showed chromatin condensation and vacuolization in a fraction of cells infected with d120 but not in wild-type virus-infected cells or cells treated with dexamethasone or sorbitol. We conclude that AIF is translocated to the nucleus in infected cells but apoptosis does not ensue in wild-type-infected cells. HEL fibroblasts infected with the d120 virus exhibit symptoms of classical apoptosis, such as cytochrome c release and cleavage of poly(ADP-ribose) polymerase observed also in cells undergoing caspase 3-dependent programmed cell death in which AIF is either not involved or not a contributory factor.

[Factors affecting transformation of Agrobacterium tumefaciens and their application on cereals]

Agrobacterium tumefaciens mediated genetic transformation is the method most widely used in plant transformation. How to improve its transformation efficiency and extend its host range to include most cereals is what people concern about. There are many factors that influence the transformation efficiency, including the wounding response of plants, attachment of bacteria, induction of virulent gene, DNA repair and replication activity of plant cells, state of explant, etc. Recent research has proved that cerelas can be transformed effectively by A. tumefaciens under suitable conditions. This paper reviewed the recent progress in the two aspects.

[Nonsyndromic cleft lip with or without cleft palate in Chinese population: analysis of 3766 cases]

A retrospective study was conducted to evaluate the variation trend in the incidence and epidemiological characteristics of nonsyndromic cleft lip with or without cleft palate in Chinese population. From 1988 to 1992, data were collected from more than 500 hospital-based units involved in a monitoring program and were analyzed by the National Center for Birth Defects Monitoring. The monitored subjects were the hospitalized births from 28 weeks gestation to a period within 7 days after delivery, which included 3246 408 perinatals and 3766 cases. The total incidence of nonsyndromic cleft lip with or without cleft palate was 11.6/10,000; the total incidence of celft lip alone was 3.8/10,000 and that of cleft lip with cleft palate was 7.8/10,000; no significant variation was noted in the annual incidence from 1988 to 1992. The incidence in males was 13.3/10,000, and 9.5/10,000 in females; there was a significant difference (P < 0.01). Of all the 3766 cases, cleft lip with cleft palate accounted for 67%, unilateral cleft lip 28% and unilateral cleft lip with cleft palate 43%. Left cleft lip and left cleft lip with cleft palate constituted 21% and 29% respectively. The sex-ratio was 1.6:1 for nonsyndromic cleft lip with or without cleft palate. It could be concluded that the incidence of nonsyndromic cleft lip with or without cleft palate showed no variation trend in China. Although no difference was found between urban and rural areas, the susceptibility to the defect was higher in males than in females. Cleft lip with cleft palate was more common than other types. There was a predominance of unilateral defects, of which most were on the left side.

[Cloning and primary analysis of 3 'end genome of two alphaviruses isolated from Hainan Province of China]

OBJECTIVE

To further characterize the HBbl7 and Ml viruses isolated from Hainan Province by molecular biology.

METHODS

The fragment containing partial El and 3'untranslated region of each of the viral isolate was amplified by RT-PCR, then subcloned. Recombinant was screened and sequenced. Analysis and comparison were carried out.

RESULTS

1.6kb fragment was amplified from HBbl7 and a 1.3kb was from Ml Comparison of sequences showed, in 3'untranslated region the nucleotide homology between HBbl7 and T48, the prototype of Ross River virus, is 99%, between Ml and Sagiyama virus is 98%. In the partial El sequence, the nucleotide (amino acid) homology between HBbl7 and T48 is 99%(99%),between Ml and Sagiyama virus is 97%(99%), and between Ml and Cetah virus is 94% (98%).

CONCLUSIONS

Sequence analysis showed HBb17 virus belongs to Ross River virus, Ml virus belongs to Sagiyama virus or Cetah virus.

[Experimental studies on exons 5-8 of p53 gene mutation in laryngeal squamous cell carcinoma]

This study was designed to detect the point mutations of exons 5-8 of p53 gene in laryngeal squamous cell carcinoma (LSCC) and analyze their relationship. The detection of fresh tumor samples from LSCC patients was performed using silver staining PCR-SSCP method. From among 60 patients samples, 47 were positive in SSCP. Mutation rate was 78.3% (47/60). The results showed that the prevalence of p53 mutations in LSCC subjected to silver staining PCR-SSCP test were 50% (30/60) in exon 5, 11.67%(7/60) in exon 6, 41.6%(25/60) in exon 7, and 25%(15/60) in exon 8. The majority of the mutations were found in exon 5 and exon 7. Exon 5 and exon 7 of p53 gene may be the mutation hotspot in LSCC; they may be the critical position easily attacked by some carcinogen factors relating to LSCC.

Efficient method for evaluation of the diffraction efficiency upper bound of diffractive phase elements

The theoretical diffraction efficiency upper limit of diffractive phase elements (DPE's) with finite apertures is investigated. A successful numerical method of evaluating the efficiency upper bound of DPE's is proposed. The method includes a hybrid optimization procedure that combines a genetic algorithm with the conjugate gradient method. This efficient global optimization technique can also be used to design DPE's. Simulation computations are detailed for rotationally symmetric beam shaping in which a Gaussian profile laser beam is converted into a uniform beam. Numerical results demonstrate that the estimated diffraction efficiency upper bound is consistent with the design results.

The structure of an HIV-1 specific cell entry inhibitor in complex with the HIV-1 gp41 trimeric core

The three-dimensional structure of the complex between an HIV-1 cell-entry inhibitor selected from screening a combinatorial library of non-natural building blocks and the central, trimeric, coiled-coil core of HIV-1 gp41 has been determined by X-ray crystallography. The biased combinatorial library was designed to identify ligands binding in nonpolar pockets on the surface of the coiled-coil core of gp41. The crystal structure shows that the non-peptide moiety of the inhibitor binds to the targeted cavity in two different binding modes. This result suggests a strategy for increasing inhibitor potency by use of a second-generation combinatorial library designed to give simultaneous occupancy of both binding sites.

[Acoustic densitometry for quantification of renal allografts microcirculation and microstructure]

OBJECTIVE

To establish a new method for observing renal allografts microcirculation and microstructure with acoustic densitometry (integrated backscatter, contrast, second harmonics).

METHODS

27 patients with renal allografts were investigated by Doppler, IBS, contrast and second harmonics. Renal allografts failed age in 5 patients 20-61 years. Intravenous injection of SHU-508A was given, compared with pre-injection by quantitative assessment of acoustic densitometry (AD) of renal microstructure.

RESULTS

There was a significant difference in the peak intensity, the area under the curve and the half-time of wash-out between pre-injection and injection contrast agent. The wish-in and wish-out curve was shown in a peak shape. The renal allografts with acute rejection were significantly lower than the control group in AD (P < 0.05). No contrast opacification of renal microstructure was present in 5 failed renal allografts and the wish-in and wish-out curve appeared in a straight line shape.

CONCLUSION

AD is safe, and efficient in assessing renal allografts microstructure. It more sensitive in detecting allograft complication such as rejection than Doppler.

Neuropeptide Y secretion from bovine chromaffin cells inhibits cyclic AMP accumulation

Neuropeptide Y (NPY) is secreted from bovine chromaffin cells in response to nicotinic receptor stimulation and may exhibit autocrine, paracrine or endocrine effects. Stimulation of bovine chromaffin cells with nicotine followed by the addition of forskolin (FSK) to the media results in a decrease in cyclic AMP accumulation compared to that seen in the absence of nicotine. Pertussis toxin (PTX) treatment or the addition of BIBP 3226, a selective NPY Y1 receptor antagonist prevents the inhibitory effect of nicotine. Fractionation of media obtained from cells stimulated with nicotine reveals an NPY-like substance that inhibits FSK-stimulated cAMP accumulation. Thus, an NPY-like substance can be secreted from bovine chromaffin cells in quantities sufficient to inhibit FSK-stimulated cAMP accumulation. These results suggest that NPY can act in an autocrine fashion to regulate chromaffin cell function.