Human and mouse monoclonal antibodies to blood group A substance, which are nearly identical immunochemically, use radically different primary sequences

A human monoclonal antibody (HuA) specific for blood group A substance with two fucose groups was found to be immunochemically almost identical with that of a previously characterized mouse monoclonal anti-A, AC-1001. The VH and VL chain cDNAs of HuA were sequenced and compared with those of AC-1001. The human and mouse antibodies used VH and Vk genes that came from different families and shared minimal nucleotide and amino acid sequence identity. Thus, two antibodies from two different species can use evolutionarily unrelated sequences to bind the same carbohydrate epitope. The cloned HuA VH and VL genes were then transfected into a mouse myeloma cell line and re-expressed, together, and each separately with an irrelevant VH or VL. Only the original HuA VH and Vk had anti-A activity, demonstrating that both the heavy and light chains contributed to specificity.

Distal phalanx replantation

Microsurgical replantation has been attempted in the distal phalanx of the digits. Twenty-three complete, single digit amputations are reviewed. The patients' ages ranged from 9 months to 48 years. Viability was 78%. Sensory recovery averaged 7 mm static two-point discrimination. Range of motion in the distal interphalangeal joint of the finger and the interphalangeal joint of the thumb averaged 64 and 51 degrees, respectively. Eight of the 17 successfully replanted digits had mild to moderate atrophy. Eighty-two percent of patients were able to use the replanted digit successfully in their daily work. We feel that distal digital replantation is rewarding. In successful cases, it always preserves acceptable function and good appearance at a price of an average of 2.3 months off work.

Antitumor agents, 145. Cytotoxic asprellic acids A and C and asprellic acid B. new p-coumaroyl triterpenes, from Ilex asprella

Three new p-coumaroyl triterpenes, asprellic acids A [1], B [2], and C [3], were isolated from the EtOH extract of dried leaves of Ilex asprella. The structures for 1-3 have been established as 3,27-di-O-trans-p-coumaroyl [1], 3-O-trans-p-coumaroyl-27-O-cis-p-coumaroyl- [2], and 3-O-cis-p-coumaroyl-27-O-trans-p-coumaroyl- [3] 3 beta,27-dihydroxyolean-12-en-28-oic acid, respectively, by spectral and chemical examinations. Asprellic acid A [1] exhibited potent cytotoxicity against the RPMI-7951 cell line with an ED50 value of 0.62 micrograms/ml, while the cytotoxicity of asprellic acid C [3] against RPMI-7951 was marginal (ED50 5.5 micrograms/ml). Compounds 1 and 3 also showed cytotoxicity against KB cells with ED50 values of 3.75 and 2.86 micrograms/ml, respectively. Asprellic acid B [2] did not show cytotoxicity (> 10 micrograms/ml) against KB or RPMI-7951 cell lines.

A point mutation in the second zinc finger of the DNA-binding domain of the androgen receptor gene causes complete androgen insensitivity in two siblings with receptor-positive androgen resistance

We have analyzed the nucleotide sequence of complementary and genomic DNAs of the human androgen receptor (AR) gene in two siblings (patients 9006 and 9030) with receptor-positive complete androgen insensitivity (Rec(+)-CAI). Northern analysis indicated that mRNA of the AR was normal in size. However, its expression was relatively reduced in both patients. Consistent with the normal androgen-binding capacity (496 and 552 fmol/mg DNA for patients 9006 and 9030, respectively) but decreased DNA-binding ability (168 fmol/mg DNA) measured in genital skin fibroblasts, no mutation was found in both N-terminal and ligand-binding domains of the AR. However, a single base substitution (G-->A) was found in the second zinc finger of the DNA-binding domain at nucleotide 2372 of the AR cDNA in both cases. This resulted in the replacement of a highly conserved arginine residue (amino acid 614) by a histidine. When the mutated receptor plasmid was cotransfected into PC-3 cells together with the reporter chloramphenicol acetyltransferase gene, chloramphenicol acetyltransferase activity was not induced by 5 alpha-dihydrotestosterone treatment, confirming that the mutation renders the AR nonfunctional and can, therefore, be held responsible for the clinical features in these patients. These results highlight the importance of Arginine-614 in the second zinc finger of the DNA-binding domain of the AR in the protein-DNA interaction.

The effect and mechanism of the prokinetic action of cisapride on gastrointestinal smooth muscle

Cisapride is a new prokinetic agent which can facilitate or restore motility throughout the entire gastrointestinal tract. Although facilitation of acetylcholine release has been suggested, the mechanism of action of cisapride is not clear. To investigate the effect and mechanism of action of cisapride, we used isolated muscle strips (with mucosa and submucosa removed) of guinea pig antrum, ileum and colon to study: (1) the dose response to cisapride, (2) the effect of antagonists (atropine and tetrodotoxin) on the stimulatory effect of cisapride. Besides these studies, we also used 3H-acetylcholine release method to investigate the acetylcholine release effect of cisapride. Cisapride elicited a dose-related enhancement of baseline activity (motility index) on the antrum and contraction on the ileum and colon at the dose of 4, 40 and 400 nM. At higher doses (4 microM) cisapride caused inhibition. This bell-shaped dose response curve suggested that cisapride might be autoinhibitory or that the receptors of cisapride might consist of high affinity stimulatory and low affinity inhibitory sites. The stimulatory responses elicited by cisapride (400 nM) were not significantly inhibited by atropine and tetrodotoxin in the antrum, ileum and colon. This suggested that cisapride might act directly on the smooth muscle. Cisapride (400 nM) evoked a rather small increase of 3H-acetylcholine release on the antrum, ileum and colon. Because the percentage of increase was small and we had demonstrated that the stimulatory effects of cisapride were not blocked by atropine and tetrodotoxin, the acetylcholine release effect of cisapride was considered unimportant.

VH gene expression and regulation in the mutant Alicia rabbit. Rescue of VHa2 allotype expression

Rabbits of the Alicia strain, derived from rabbits expressing the VHa2 allotype, have a mutation in the H chain locus that has a cis effect upon the expression of VHa2 and VHa- genes. A small deletion at the most J-proximal (3') end of the VH locus leads to low expression of all the genes on the entire chromosome in heterozygous ali mutants and altered relative expression of VH genes in homozygotes. To study VH gene expression and regulation, we used the polymerase chain reaction to amplify the VH genes expressed in spleens of young and adult wild-type and mutant Alicia rabbits. The cDNA from reverse transcription of splenic mRNA was amplified and polymerase chain reaction libraries were constructed and screened with oligonucleotides from framework regions 1 and 3, as well as JH. Thirty-three VH-positive clones were sequenced and analyzed. We found that in mutant Alicia rabbits, products of the first functional VH gene (VH4a2), (or VH4a2-like genes) were expressed in 2- to 8-wk-olds. Expression of both the VHx and VHy types of VHa- genes was also elevated but the relative proportions of VHx and VHy, especially VHx, decreased whereas the relative levels of expression of VH4a2 or VH4a2-like genes increased with age. Our results suggest that the appearance of sequences resembling that of the VH1a2, which is deleted in the mutant ali rabbits, could be caused by alterations of the sequences of the rearranged VH4a2 genes by gene conversions and/or rearrangement of upstream VH1a2-like genes later in development.

Microsurgical reconstruction of distal digits following mutilating hand injuries: results in 121 patients

From 1982-1989, 152 mutilated distal digits were reconstructed with microsurgical foot tissue transfers in 121 patients. These various foot tissues included wrap-around flaps or pulp from the great toe, second toe, or third toe, as well as partial toe, nail, web space skin, and other portions of the foot. The reconstructions were carried out primarily and secondarily in 78 and 74 patients respectively. The immediate success rate was 98%. Most of the patients were satisfied with both the cosmetic appearance and the functional result. This relatively minor microsurgical foot tissue transfer proved to be an ideal reconstructive option for distal digital defects.

VH gene expression and regulation in the mutant Alicia rabbit. Rescue of VHa2 allotype expression

Rabbits of the Alicia strain, derived from rabbits expressing the VHa2 allotype, have a mutation in the H chain locus that has a cis effect upon the expression of VHa2 and VHa- genes. A small deletion at the most J-proximal (3') end of the VH locus leads to low expression of all the genes on the entire chromosome in heterozygous ali mutants and altered relative expression of VH genes in homozygotes. To study VH gene expression and regulation, we used the polymerase chain reaction to amplify the VH genes expressed in spleens of young and adult wild-type and mutant Alicia rabbits. The cDNA from reverse transcription of splenic mRNA was amplified and polymerase chain reaction libraries were constructed and screened with oligonucleotides from framework regions 1 and 3, as well as JH. Thirty-three VH-positive clones were sequenced and analyzed. We found that in mutant Alicia rabbits, products of the first functional VH gene (VH4a2), (or VH4a2-like genes) were expressed in 2- to 8-wk-olds. Expression of both the VHx and VHy types of VHa- genes was also elevated but the relative proportions of VHx and VHy, especially VHx, decreased whereas the relative levels of expression of VH4a2 or VH4a2-like genes increased with age. Our results suggest that the appearance of sequences resembling that of the VH1a2, which is deleted in the mutant ali rabbits, could be caused by alterations of the sequences of the rearranged VH4a2 genes by gene conversions and/or rearrangement of upstream VH1a2-like genes later in development.

Evaluation issues in the Drake Chemical Workers Notification and Health Registry Study

The Drake Chemical Workers' Health Registry combined notification of workers about bladder cancer risk with access to a free program for screening and diagnosis. Evaluation of the project has given rise to several findings and new research questions. Findings in this article illustrate the following evaluation issues: 1) studying the combination of strategies that are most effective and cost effective to notify workers of their disease risks, 2) determining the realistic yield from strategies to gain participation in health screening and other protective services for notified workers, 3) identifying the notification strategies that were most effective for different kinds of participants, 4) using process evaluation to identify key activities for ensuring continued participation of cohort members in screening, and 5) examining the extent to which participants are willing to quit smoking to protect their health.

Quantitative autoradiography of 3H-paroxetine binding sites in rat brain

The use of 3H-paroxetine as a ligand for quantitative autoradiography of serotonin (5-HT) transport sites was optimized, and the distribution of 3H-paroxetine binding sites in rat brain was studied. Under the conditions described, 3H-paroxetine binding in forebrain sections was of high affinity and saturable, with a Kd of 0.18 +/- 0.02 nM (mean +/- SEM) and Bmax of 268 +/- 12 fmol/mg of protein (n = 3). Nonspecific binding was 10.7% +/- 1.0 of the total binding (n = 8). The distribution of 3H-paroxetine binding sites closely matched the regional distribution of 5-HT nerve terminals and cell bodies. The highest concentrations of 3H-paroxetine binding sites were found in the dorsal raphe nucleus (563 +/- 55 fmol/mg tissue, n = 4), and high densities of binding were also found in the locus coeruleus, medial forebrain bundle, substantia nigra, several limbic structures (amygdala, hippocampus, hypothalamus, olfactory tubercle, septum, and thalamus), and components of the visual relay system (superior colliculus and the lateral geniculate body). Although lesioning of 5-HT neurons with p-chloroamphetamine (PCA) drastically eliminated 3H-paroxetine binding in most regions of the rat brain, significant binding remained in the raphe nuclei and medial forebrain bundle suggesting that 3H-paroxetine binding in these regions was to presynaptic sites on cell bodies or axons relatively resistant to PCA.

Experience of 73 free groin flaps

The free groin flap has gradually lost its popularity due to the disadvantages relating to the pedicle and the plethora of new donor sites. The purpose of this article is to re-evaluate this time-honoured free flap and to demonstrate its reliability and versatility through a review of 73 free groin flaps performed between 1985 and 1990. 7% of free transfers (total 1096 cases) in our institution were free groin flaps. The complication rate was 8% (three complete failures and three partial failures). This result is acceptable and not so high as other reports have described. The artery discrepancy is the main cause of the complication rate. Two special techniques to gain additional diameter of vessel size to overcome the pedicle disadvantages are stressed. The groin flap has proved to be useful and still deserves consideration in reconstructive procedures.

Spontaneous bacterial peritonitis in patients with hepatitis B-related cirrhosis and hepatocellular carcinoma

To delineate the natural clinical course of spontaneous bacterial peritonitis in hepatitis B-related cirrhosis and to determine if it occurs in hepatocellular carcinoma, a prospective survey was conducted in 262 patients over 2 1/2 years. The in-hospital incidence and mortality rates of spontaneous bacterial peritonitis were 21.6% and 36.4%, respectively, in cirrhosis and 7.3% and 50% in hepatocellular carcinoma. In cirrhosis, the cumulative probability of annual recurrence of spontaneous bacterial peritonitis was 47.3%, which was significantly higher than the annual probability of occurrence of 11.3% in those with no previous attack (P less than 0.0001). The cumulative probability of annual survival was 27.6% in the spontaneous bacterial peritonitis patients, significantly lower than the probability of 64.0% in the control group (P = 0.0001). A univariate analysis, with Kaplan-Meier curves compared by the Mantel-Cox test, and subsequent multivariate analysis by stepwise Cox regression procedure were used to evaluate 37 variables recorded immediately after admission. Blood urea nitrogen concentration greater than 10.5 mmol/L urea (greater than 30 mg/dL) and ascitic fluid protein concentration less than 7.35 g/L (less than 735 mg/dL) were found to be the only significant predictors of lower annual survival; ascitic fluid protein concentration less than 7.50 g/L (less than 750 mg/dL) was the only significant predictor of higher annual recurrence. The authors conclude that spontaneous bacterial peritonitis has a high risk of recurrence in hepatitis B-related cirrhosis and that the same disease occurring in patients with hepatocellular carcinoma is related to the underlying cirrhosis rather than the hepatocellular carcinoma.

3H-paroxetine binding in brains of alcoholics

High affinity 3H-paroxetine binding was studied in human frontal cortex and hippocampus obtained from normal controls and alcoholics. On the basis of Scatchard analyses, a significant decrease in the maximal number of binding sites (Bmax) was found in the hippocampus of alcoholics (n = 8) as compared with that of controls (n = 10) (mean +/- SD = 63 +/- 35 vs. 114 +/- 70 fmoles/mg protein). There was no significant difference in the dissociation constants (Kd) between the two groups. The presumed effect of chronic alcohol abuse on 3H-paroxetine binding may be region-specific since no significant difference in either Bmax or Kd for 3H-paroxetine binding was found in the frontal cortex between normal controls and alcoholics. No significant correlation of 3H-paroxetine binding with age or postmortem interval was observed. The decrease in 3H-paroxetine binding in the hippocampus of alcoholics is probably indicative of reduced density of serotonergic nerve terminals either as a preexisting condition or as a result of neuronal damage caused by ethanol or the sequelae of alcoholism, such as nutritional deficiencies.

Cloning and characterization of the carp prolactin gene

A carp genomic DNA clone containing the carp prolactin (Prl) gene was isolated with carp Prl cDNA as a probe. The organization of the carp Prl gene was determined by restriction nuclease mapping and nucleotide sequencing. The Prl gene comprises approx. 2.8 kilobasepairs (kb) of DNA including the 5'-flanking region, five exons, four introns and the 3'-flanking region. Analysis of the 5'-flanking region reveals (1) the sequence TATATAAT at positions -38 to -31 upstream from the cap site which was found to be a guanine residue, and (2) the palindrome, CTCATTGCATATACAAATGAG at positions -79 to -59. The carp Prl gene matches with the reported cDNA except for one difference in coding region and five in the 3'-flanking region, while the encoded amino acid sequences are identical. The arrangement of exons and introns is very similar to that seen in carp GH as well as mammalian Prl, which, however, have much longer introns.

Two families of monoclonal antibodies to alpha(1----6)dextran, VH19.1.2 and VH9.14.7, show distinct patterns of J kappa and JH minigene usage and amino acid substitutions in CDR3

Nine groove-type mAb to alpha(1----6)dextran were cloned and sequenced. Together with previous reports from this laboratory, the VH and VL of 34 mAb have been sequenced, in which 10 VH19.1.2 and 11 VH9.14.7 combined with the V kappa-Ox1 gene to form two major families of anti-alpha(1----6)dextrans. The same D minigene (DFL16) was used by all VH19.1.2 and VH9.14.7 mAb; however, the patterns of JH and J kappa usage are quite different. VH19.1.2 mAb used only JH3 and J kappa 2, whereas VH9.14.7 mAb used three JH (JH1, JH2, and JH3) and all four active J kappa (J kappa 1, J kappa 2, J kappa 4, and J kappa 5). Relative uniformity in the lengths of VH CDR3 and the junctional sequences is seen in both families. Some mAb from different mouse strains share common structural features. The differences in idiotypic specificities and in the amino acid sequences suggest that VH19.1.2 and VH9.14.7 may differ in the conformation of CDR1 and CDR2. Combining with V kappa-Ox1 gene to generate groove-type combining sites to the single site-filling epitope of alpha(1----6)dextran, the two VH chains may require certain conformations of CDR3. Whether such conformational requirements influence the choice of J minigenes, the selection of the length of VH CDR3 and the sequences at junctions, are discussed.

Two families of monoclonal antibodies to alpha(1----6)dextran, VH19.1.2 and VH9.14.7, show distinct patterns of J kappa and JH minigene usage and amino acid substitutions in CDR3

Nine groove-type mAb to alpha(1----6)dextran were cloned and sequenced. Together with previous reports from this laboratory, the VH and VL of 34 mAb have been sequenced, in which 10 VH19.1.2 and 11 VH9.14.7 combined with the V kappa-Ox1 gene to form two major families of anti-alpha(1----6)dextrans. The same D minigene (DFL16) was used by all VH19.1.2 and VH9.14.7 mAb; however, the patterns of JH and J kappa usage are quite different. VH19.1.2 mAb used only JH3 and J kappa 2, whereas VH9.14.7 mAb used three JH (JH1, JH2, and JH3) and all four active J kappa (J kappa 1, J kappa 2, J kappa 4, and J kappa 5). Relative uniformity in the lengths of VH CDR3 and the junctional sequences is seen in both families. Some mAb from different mouse strains share common structural features. The differences in idiotypic specificities and in the amino acid sequences suggest that VH19.1.2 and VH9.14.7 may differ in the conformation of CDR1 and CDR2. Combining with V kappa-Ox1 gene to generate groove-type combining sites to the single site-filling epitope of alpha(1----6)dextran, the two VH chains may require certain conformations of CDR3. Whether such conformational requirements influence the choice of J minigenes, the selection of the length of VH CDR3 and the sequences at junctions, are discussed.

The complete nucleotide sequence of the growth-hormone gene from the common carp (Cyprinus carpio)

We have isolated and sequenced a phase clone from a common carp (Cyprinus carpio) genomic library that carries a gene encoding growth hormone (GH). This gene consists of five exons and four introns spanning a region of about 3 kilobase pairs. Its exons correspond with one of two reported cDNAs of carp GH except for nine differences in the nucleotide sequence, while the encoded amino-acid sequences are identical. The sequence upstream from the transcription start point contains two tandem repeats of AACTCTCATG (from -85 to -62) and the typical TATA box. All the introns start with a consensus GT dinucleotide and end with AG. The arrangement of exons and introns is very similar to that seen in mammalian GH, but quite different from the GH genes of rainbow trout and Atlantic salmon.

Interleukins, signal transduction, and the immune system-mediated stress response

Overwhelming evidence indicates that the administration of cytokines such as IL-1 alpha and beta, IL-6, and TNF-1 alpha stimulates one or more components of the HPA axis. The hypothesis driving this research is that host infection and tissue injury trigger the synthesis and release of several cytokines that act locally at sites of trauma and distally upon entering the circulation. Available evidence suggests that the primary source of HPA axis-acting or circulating cytokines is activated monocytes or macrophages; therefore, a direct relationship should exist between the appearance of monokines in plasma and the subsequent appearance of pituitary-adrenocortical hormones in plasma as well. Clarification of the physiological role of monokines as mediators of the host stress response will come from in vivo studies in which the type, sequence of appearance, duration of elevation, and quantification of each monokine is monitored along with ACTH and glucocorticoids, following an appropriate immune challenge. In several recent reports, investigators have administered bacterial-derived endotoxin or LPS to stimulate the physiological events associated with infection or injury and chronicled plasma levels of IL-1, IL-6, and TNF-alpha (37,56,57). In human subjects, endotoxin challenge enhanced plasma TNF-alpha levels by 1 hour, which returned to basal levels by 4 hours (37), whereas, IL-6 plasma activity increased at 2 hours post-challenge and returned to baseline by 6 hours (56). Thus, both of these monokines are implicated as possible acute activators of the HPA axis. In perhaps the most revealing study to date, LPS challenge of mice indicated both a differential appearance and disappearance rate in serum for TNF-alpha and IL-1 and a differential regulation of these monokines by glucocorticoid feedback (57). Serum TNF was detected 45 minutes post-LPS, peaked by 1 hour, and returned to control levels by 3 hours. Serum corticosterone concentrations rose rapidly over a time course similar to that of TNF. Even after serum TNF concentration had returned to basal conditions, corticosterone levels remained maximally elevated, and serum corticosterone was still significantly above basal levels 24-hour post-LPS. The rapid return of circulating TNF to pre-LPS challenge levels appeared to be regulated by negative glucocorticoid feedback, because TNF remained maximally elevated for at least 6 hours in adrenalectomized or hypophysectomized mice. LPS-induced levels of IL-1 were delayed as compared to serum TNF, peaked at 4 hours, and remained elevated even at 24 hours.(ABSTRACT TRUNCATED AT 400 WORDS)

[A community-based study on risk factors of hypertension in Luh-Guu Township]

This is a community-based study on hypertension conducted in 1987 to assess the risk of demographic factors and life style of inhabitants aged over 30 in Luh-Guu Township. One-stage cluster sampling was applied. Through home visit interview, the height, weight, and blood pressure as well as demographic and life style data were taken, and 1171 (57.4%) valid data were completed. Hypertension was defined by American National Heart, Lung, Blood Institute as BP greater than = 140/90mmHg. The prevalence of hypertension was 29.2% (the prevalence was 13.4% if defined by the WHO criteria), and only 27.4% of those hypertensives were self-aware. Univariate analysis found that age, educational level, marital status, job condition, smoking habit, father's hypertension history, and usage of contraceptive were correlated with hypertension. With obesity index in addition to the above 6 factors, except contraceptive usage, as independent variables, the multiple logistic regression analysis showed that, only age and obesity index were significantly correlated with hypertension and the best model were fitted.

[Toxicity experiment on Sargassum, radix Knoxiae, radix Ransul and flos Genkwa against radix Glycyrrhizae in the antagonism of 18 Chinese drugs]

In order to further look into the cause of the antagonisms in the 18 Chinese medicinal herbs, stimulation and toxicity experiments, with five Chinese medicinal herbs (Sargassum Radix Knoxiae, Radix Kansul and Flos Genkwa against Radix Glycyrrhiza) as a group, were done in healthy rats and rabbits.

Effect of estrogen on the expression of a cell-surface antigen associated with rat anterior pituitary somatotrophs

The long-term in vivo effect of diethylstilbestrol (DES) on the expression of a cell-surface antigen associated with the anterior pituitary somatotroph was studied in two strains of female rats using double immunofluorescence techniques. Mab WHC-1, a recently generated and characterized monoclonal antibody, was used to detect the antigen associated with somatotrophs, whereas rabbit anti-rat prolactin (rPRL) and anti-human growth hormone (hGH) antisera were used to identify mammotrophs and somatotrophs, respectively. In F344 rats, Mab WHC-1-positive cells increased from 13.8 +/- 0.5% of total pituitary cells in normal anterior pituitaries to 34.2 +/- 4.0% in DES-induced pituitary tumors. The number of mammotrophs also increased significantly from 58.0 +/- 3.2% in controls to 75.9 +/- 2.2% in tumors. On the other hand, somatotrophs decreased significantly in number following ovariectomy (OVX) and DES implantation (19.7 +/- 0.5% vs. 6.1 +/- 1.2%). Based on double immunofluorescence, the percentage of Mab WHC-1-positive cells, which were somatotrophs, decreased from 85.5 +/- 2.7% in normal controls to 6.7 +/- 1.5% in DES-induced tumors. On the other hand, the percentage of Mab WHC-1-positive cells which were mammotrophs increased significantly from 14.0 +/- 1.4% to 86.1 +/- 1.8% following OVX and DES implantation. A similar change was found in the number of somatotrophs and mammotrophs following the same treatment in Sprague-Dawley (SD) rats which did not develop pituitary tumors. In contrast to F344 rats, the number of Mab WHC-1-positive cells in SD rats decreased significantly from 32.4 +/- 2.8% in sham-operated controls to 19.3 +/- 2.9% in OVX + DES-implanted rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of exocrine pancreatic secretion by opiates is mediated by suppression of cholinergic transmission: characterization of receptor subtypes

This study evaluates the hypothesis that opiates suppress pancreatic enzyme secretion by inhibiting cholinergic transmission in the pancreas. Rat pancreatic lobules were incubated in 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid-Ringer's buffer and amylase release in response to KCl depolarization of the intrapancreatic nerve in the absence or presence of specific opiate subtype receptor agonists was studied. Depolarization by 75 mM KCl resulted in a 5-fold increase in amylase output. Pretreatment with 1 microM atropine inhibited completely the KCl-stimulated amylase release, suggesting stimulation via a cholinergic pathway. Addition of methionine enkephalin or 2-D-penicillamine-5-D-penicillamine-enkephalin [( D-Pen2, D-Pen5]enkephalin, a specific delta receptor agonist) inhibited KCl-stimulated amylase release in a dose-dependent fashion. Methionine enkephalin (1 microM) or [D-Pen2, D-Pen5]enkephalin inhibited KCl-stimulated amylase release by 32 +/- 4 and 45 +/- 4%, respectively. Addition of 1 microM ICI 174,864 (a delta opiate receptor antagonist) blocked the inhibitory effect of [D-Pen2, D-Pen5]enkephalin. Upjohn 50,488H (1 microM, a specific kappa agonist) and 1 microM Tyr-D-Ala-Gly-MePhe-Gly-ol (a specific mu agonist) had no effect. Methionine enkephalin had no effect on carbachol (1 microM)-stimulated amylase release. These data suggest that methionine enkephalin acts on a delta opiate receptor located on postganglionic cholinergic neurons. To examine the ability of methionine enkephalin to alter acetylcholine release from pancreatic tissue, pancreatic lobules were incubated with [3H]choline and the release of synthesized [3H]acetylcholine was stimulated by KCl. Depolarization of the nerves with 75 mM KCl increased [3H]acetylcholine release by 35 +/- 5% over basal.(ABSTRACT TRUNCATED AT 250 WORDS)