cDNA cloning and pharmacological characterization of an opioid receptor with high affinities for kappa-subtype-selective ligands

The amino acid sequence of a rat opioid receptor, designated as ROR-D, has been deduced by cloning and sequencing the cDNA. The ROR-D expressed from the cDNA exhibits high affinities for ligands selective for the opioid receptor kappa-subtype and low affinities for ligands selective for the delta- and mu-subtypes. RNA blot hybridization analysis indicated that ROR-D mRNA is distributed in cerebrum and brainstem but not in cerebellum.

Central action of C-type natriuretic peptide on vasopressin secretion in conscious rats

The effect of intracerebroventricular injection of C-type natriuretic peptide (CNP) on arginine vasopressin (AVP) secretion was studied in conscious rats, and was compared to that of atrial natriuretic peptide (ANP). The AVP secretion induced by central injection of 0.1 nmol angiotensin II was significantly suppressed by the pretreatment with 1 nmol CNP. ANP at a dose of 0.1 nmol elicited almost equivalent suppressive action to 1 nmol CNP. Considering that CNP is a specific ligand for ANP-B receptor, while ANP is that for ANP-A receptor, the result demonstrates that CNP possesses the similar central action to ANP, and suggests that the distribution of ANP-A and ANP-B receptors and/or their affinity towards each natriuretic peptide are different in the central nervous system.

[Anesthetic management of an infant with Menkes disease]

Menkes disease is a rare, sex-linked recessive disorder characterized by kinky hair, convulsion, mental retardation, bone and connective tissue lesions, and hypothermia. These symptoms have been attributed to suppression of copper-dependent enzymes resulting from copper deficiency. We report a case of a 7-month-old infant with Menkes disease who underwent repair of inguinal hernia. Anesthesia was maintained with sevoflurane-N2O-O2, and the operation was carried out uneventfully. Although the patient had been medicated with anticonvulsants preoperatively, transient seizure occurred in the recovery room. We also discuss pathophysiology and anesthetic management of a patient with Menkes disease.

Effect of prostaglandin E1 on preservation injury of canine liver grafts preserved in UW solution

This study investigated whether prostaglandin E1 (PGE1) could reduce hepatic injury to the liver graft caused by harvesting and 24-h preservation in University of Wisconsin (UW) solution in a canine model. The PGE1-treated group was intravenously administered 0.5 microgram/kg per minute of PGE1 for 30 min before harvesting, as well as a concentration of 1 mg/l PGE1 in the washout and UW solutions. In both the PGE1-treated and the control group, all recipients survived for 1 week or more after transplantation. Arterial ketone body ratio (AKBR) remained over 1.0 in the early postoperative period. The PGE1 group showed significant reductions in guanase, GOT, and LDH during the early postoperative period compared to the untreated control group. Histological examination disclosed partial mitochondrial swelling, hepatocyte vacuolation, and necrosis in the control group, while such abnormalities were rarely seen in the PGE1 group. These results suggest that PGE1 can effectively reduce hepatic injury to liver grafts preserved in UW solution prior to transplantation.

[A case of xanthofibroma of the skull]

The authors describe a case of xanthofibroma of the skull. A 53-year-old female was admitted to our hospital in September, 1991, with subarachnoid hemorrhage due to a ruptured aneurysm of the anterior communicating artery. The roentgenogram of her skull incidentally revealed the presence of a radiolucent (a punched out) lesion of about 20 x 25 mm in the right occipital bone. On computed tomography (CT), the mass was seen to be mainly localized in the diploe, and the outer table of the skull was thinned. On both T1 and T2 weighted magnetic resonance image (MRI), the mass showed a high intensity signal equivalent to that found in adipose tissue. The bony tumor was totally removed. Histology revealed a collection of foamy cells, benign fibrous tissues and so on which led to a diagnosis of xanthofibroma of the skull without hyperlipidemia. Xanthofibroma of the skull is extremely rare. To our knowledge, including our case, only three cases have been reported.

Distribution of ubiquinone and ubiquinol homologues in rat tissues and subcellular fractions

The oxidized (UQox) and reduced (UQred) forms of ubiquinone (UQ) homologues in rat tissues and subcellular fractions were analyzed to elucidate their distribution and physiological role. UQ-9 and UQ-10 were detected in all tissues studied, and UQ-9 was the predominant homologue. The total amount of UQox-10 and UQred-10 was 20-50% that of UQox-9 and UQred-9. The levels of these homologues were highest in heart with lesser amounts occurring in kidney, liver and other organs. In liver and blood plasma, the UQred homologue amounted to 70-80% of the total UQ (UQox + UQred = t-UQ). UQred was less than 30% of t-UQ in other tissues and blood cells. t-UQ was much higher in leukocytes and platelets in blood than in erythrocytes. In erythrocytes, t-UQ was exclusively located in the cell membranes. UQox and UQred were also found in all subcellular fractions isolated from liver and kidney in about the same ratio as UQred/t-UQ was present in the whole organ. The levels of UQox and UQred per mg protein in subcellular fractions from liver were highest in mitochondria, with lesser amounts present in plasma membranes, lysosomes, Golgi complex, nuclei, microsomes and cytosol. In the mitochondria, the outer membranes were richer in t-UQ than the inner membranes. In the Golgi complex, the light and intermediate fractions were rich in t-UQ when compared to the heavy fraction. The possible physiological role of UQox and UQred in tissues and subcellular fractions is discussed.

Comparison of CNS effects of propofol and thiopentone in cats

Using cats with chronically implanted brain electrodes, we have compared the effects of propofol on CNS electrical activities with those of thiopentone. Ten cats were allocated to receive either propofol (n = 5) or thiopentone (n = 5). Cats were anaesthetized initially with 4% halothane in oxygen. The trachea was intubated and the lungs ventilated mechanically. A femoral artery and a vein in a forepaw were cannulated for arterial pressure monitoring and fluid infusion. After the inspired concentration of halothane was maintained at 0.5%, EEG in the cortex, the amygdala and the hippocampus, somatosensory evoked potential (SEP) and reticular multi-unit activity (R-MUA) were recorded. Incremental doses of propofol or thiopentone were administered i.v. at 5-min intervals during 0.5% halothane anaesthesia. The cumulative doses of propofol and thiopentone were 2, 5, 10 and 20 mg kg-1, and 4, 10, 20 and 40 mg kg-1, respectively. Arterial pressure was maintained in excess of 100 mm Hg systolic by infusion of phenylephrine. All cats in the propofol group survived, but two in the thiopentone group died after the administration of thiopentone 40 mg kg-1. Changes observed in CNS activity were dose-related in all cases. The EEG changed with the increments of doses of propofol or thiopentone, from fast, small amplitude to complexes of fast and slow, large amplitude activities, burst suppression and flat EEG. SEP latency was prolonged by both agents: the peak latency of N1 changed from 15 (SD 2) ms to 20 (5) ms with propofol 20 mg kg-1, and from 14 (1) ms to 27 (2) ms with thiopentone 40 mg kg-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatic blood flow and energy metabolism during hypotension induced by prostaglandin E1 and nicardipine in rabbits: an in vivo magnetic resonance spectroscopic study

Hepatic blood flow (HBF) and energy metabolism during moderate hypotension induced by prostaglandin E1 (PGE1) and nicardipine were studied by in vivo magnetic resonance spectroscopy. HBF was determined by the deuterated water clearance method by using deuterium magnetic resonance spectroscopy, and energy metabolism was estimated from the changes in the levels of adenosine triphosphate and inorganic phosphate by using phosphorus (31P) magnetic resonance spectroscopy. Mean arterial blood pressure was intentionally reduced to 60% of control with PGE1 (n = 5) or nicardipine (n = 5). The HBF decreased by 38% and by 50% during the hypotension induced by PGE1 and nicardipine, respectively. The level of adenosine triphosphate decreased by 12% and that of inorganic phosphate increased by 80% during nicardipine-induced hypotension, whereas the corresponding levels showed no remarkable changes during PGE1-induced hypotension. After the cessation of drug administration, mean arterial blood pressure and HBF recovered to the control levels in the PGE1 group, but not completely in the nicardipine group. In the latter group, the level of inorganic phosphate did not recover either. These results indicate that during hypotension induced with PGE1 hepatic circulation and metabolism are conserved to a greater extent than during hypotension induced with nicardipine.

A transmembrane protein with a cdc2+/CDC28-related kinase activity is required for signaling from the ER to the nucleus

In eukaryotic cells, the accumulation of unfolded proteins in the endoplasmic reticulum (ER) triggers a signaling pathway from the ER to the nucleus. Several yeast mutants defective in this pathway map to the ERN1 gene, which protects cells from lethal consequences of stress by signaling for increased expression of BiP and other ER proteins. ERN1 encodes a 1115 amino acid transmembrane protein (Ern1p) whose glycosylated N-terminal portion is located inside microsomes and whose cytoplasmic C-terminal portion carries an essential protein kinase activity. We postulate that Ern1p is the proximal sensor of events in the ER and that binding of ligand causes transduction of information across the ER membrane, leading to activation of a specific set of transcription factors.

Tyr-D-Arg-Phe-beta-Ala-NH2, a novel dermorphin analog, impairs memory consolidation in mice

Tyr-D-Arg-Phe-beta-Ala-NH2 (TAPA), a novel dermorphin analog with high selectivity and affinity for mu-opioid receptors, was administered intracerebroventricularly to mice before or immediately after training in a one-trial step-down type passive avoidance task. The pre- and post-training administration of TAPA (0.3 and/or 3 ng) impaired retention performance 24 h after training. In particular, the post-training administration of TAPA was much more effective because a lower dose (0.3 ng) of TAPA exclusively inhibited retention performance. The amnesic effects of TAPA were reversed by the mu-selective opioid antagonist beta-funaltrexamine (5 micrograms, i.c.v.). In addition, TAPA (0.3 and 3 ng) had no effects on nociceptive responses in a tail-flick test or on behavioral responses to electric shock during training. These results suggest that activation of mu-opioid receptors impairs passive avoidance learning, resulting in a dysfunction of memory consolidation, without affecting other behavioral responses.

Primary structures and expression from cDNAs of rat opioid receptor delta- and mu-subtypes

The complete amino acid sequences of rat opioid receptors (designated as ROR-A and ROR-B) have been deduced by cloning and sequencing the cDNAs. The ligand-binding properties of ROR-A and ROR-B expressed from the cloned cDNAs in Chinese hamster ovary cells correspond most closely to those of the pharmacologically defined delta- and mu-opioid receptor subtypes, respectively. RNA blot hybridization analysis revealed that cerebrum and brainstem contain both ROR-A and ROR-B mRNAs, whereas neither ROR-A nor ROR-B mRNAs can be detected in cerebellum.

Atypical form of atrioventricular septal defect without left axis deviation: relation between morphology and unusual QRS axis

OBJECTIVE

To clarify the morphological features relating to an intermediate axis or a right axis deviation in atrioventricular septal defect (AVSD).

SUBJECTS

135 patients with typical AVSD and with nine patients with atypical AVSD, characterised by a well formed atrial septum, a milder downward displacement of the atrioventricular valves, and a shorter length of the ostium primum defect.

MAIN OUTCOME MEASURES

Relation between morphology and electrocardiographic and vectorcardiographic findings; prevalence of Down's syndrome and of other cardiac anomalies.

RESULTS

All nine patients with atypical AVSD had an unusual mean frontal QRS axis compared with six of the 135 patients (4%) with typical AVSD (p < 0.01). All eight patients who underwent the vector analyses showed atypical movement of the QRS loop--that is, an initial left inferior movement in the frontal loop (eight patients) and counter-clockwise rotation in the sagittal loop (seven). The corresponding values for 119 patients with typical AVSD were 20 and 22 patients (p < 0.01). Seven patients with atypical AVSD (78%) and 55 (41%) with typical AVSD had Down's syndrome (p < 0.05). None of the twenty one patients with additional cardiac anomalies had atypical AVSD, an unusual QRS axis, or unusual movement in the QRS loop.

CONCLUSIONS

The atypical morphology, supposedly related to the degree of posteroinferior displacement of the conduction system, was one of the causes of unusual movement of the QRS loop in AVSD.

Molecular cloning and tissue distribution of a receptor for pituitary adenylate cyclase-activating polypeptide

Pituitary adenylate cyclase-activating polypeptide (PA-CAP) is a polypeptide hormone related to vasoactive intestinal polypeptide (VIP). Rat PACAP receptor cDNA was isolated from a brain cDNA library by cross-hybridization with rat VIP receptor cDNA. The recombinant PACAP receptor expressed in COS cells bound PACAP with about 1000 times higher affinity than VIP, and PACAP stimulated adenylate cyclase through the cloned PACAP receptor. The rat PACAP receptor consists of 495 amino acids, contains seven transmembrane segments, and has a significant similarity with other Gs-coupled receptors, such as VIP, glucagon, and secretin receptors. PACAP receptor mRNA was abundantly expressed in the brain, but not in the peripheral tissues except for the adrenal gland. In situ hybridization revealed a high level of expression of PACAP receptor mRNA in the hippocampal dentate gyrus, olfactory bulb, and cerebellar cortex.

Plasma amino acid profile in relation to arterial ketone body ratio in surgical patients

A total of 357 plasma amino acid profiles from 93 surgical patients were statistically analyzed in relation to the changes in arterial ketone body ratio, which reflects the hepatic mitochondrial redox state. When the arterial ketone body ratio was above 0.7, all plasma amino acid levels were within the normal range. When it was between 0.7 and 0.4, plasma levels of aspartate, glutamate, valine, isoleucine, leucine, ornithine, and arginine decreased, and plasma levels of tyrosine, phenylalanine, proline, and methionine increased. Furthermore, when it was below 0.4, almost all plasma amino acids markedly increased. These results indicate that arterial ketone body ratio accurately reflects the alterations in plasma amino acid profile, and can serve as an indicator for providing nutritional support by amino acid supplement in surgical patients.

Effect of dobutamine on the arterial ketone body ratio and portal blood flow velocity in cirrhosis

We studied the relationship between the portal blood flow velocity and the arterial ketone body ratio in patients with chronic liver disease receiving a dobutamine infusion. We used an ultrasonic Doppler duplex system to evaluate the portal blood flow velocity. Dobutamine was given intravenously at 5 micrograms/kg/min for 20 min. Dobutamine infusion induced smaller changes in the portal blood flow velocity and ketone body ratio in liver cirrhosis than in chronic hepatitis. The existence of shunts and the poor increase of the cardiac index in response to dobutamine explained the limited improvement of portal blood flow velocity in cirrhosis patients. The ketone body ratio was improved by dobutamine in cirrhosis patients whose portal blood flow velocity was increased by more than 10%, while this ratio decreased when the increase of it was less than 10%. There was no change in portal oxygen extraction in the cirrhosis group, and portal oxygen uptake only increased when the portal blood flow velocity rose by more than 10%. Dobutamine should only be used to treat liver failure if the portal blood flow velocity is increased by more than 10% or the arterial ketone body ratio is improved by a test infusion.

Inhibition of placental thyroxine 5-deiodinase activity decreases amniotic fluid concentration of 3,3',5'-triiodothyronine in rat

We investigated whether the inhibition of placental T4 5-deiodinase (5-D) activity would decrease the amniotic fluid (AF) concentration of rT3. Iopanoic acid (IOP) was used to inhibit placental T4 5-D activity. From gestation days 14 to 17, a group of rats received IOP (10 mg/100 g bw/day, sc) once daily in experiment (exp) 1, and received it (40 mg/100 g bw/day) four times daily in exp 2. In exp 2, control dams received propylthiouracil (PTU; 2 mg/100 g bw/day) instead of IOP. Methimazole and T4 were also given to all dams in exp 1 and 2. On day 17 of gestation, we collected the liver, placenta, blood, and AF of each animal. In the IOP-treated group in both experiments, the serum T4 concentration was significantly increased. Hepatic T4 5'-deiodinase activity was significantly decreased by either PTU or IOP administration. In both experiments placental T4 5-D activity was significantly decreased in the IOP-treated group. The concentration of rT3 in AF was significantly decreased in the IOP-treated group in exp 2 (1.71 vs. 0.75 nmol/l, P < 0.01) despite a higher serum T4 concentration. There was a significant positive correlation between placental T4 5-D activity and the concentration of rT3 in AF in exp 2 (r = 0.62, P < 0.05). These observations indicate that the inhibition of placental T4 5-D activity decreases the concentration of rT3 in rat AF, and that placental T4 5-D and the T4 concentration in maternal serum plays important roles in maintaining the concentration of rT3 in rat AF.

Electron microscopic observation of cotton cellulose degradation by exo- and endo-type cellulases from Irpex lacteus

The interaction of two highly purified cellulases, exo- and endo-type cellulases from Irpex lacteus, with pure cotton and amorphous cellulose was investigated by electron microscopy. The morphological observations indicated that exo- and endo-type cellulases are both strongly adsorbed on the internal microfibril of cotton fiber before enzymatic hydrolysis, and then initiate their action toward the internal cellulose microfibrils with retention of the original shape. The two cellulases, however, caused considerably different morphological changes in cotton cellulose, and each cellulase seems to degrade native cellulose with a distinct mode of action. In the hydrolysis of cotton with exo-type cellulase, deep transverse cracks were produced and they extended from the fiber surface to the lumen structure located inside the fibers. In contrast, it was found that there were no deep cracks on fibers treated with endo-type cellulase, but severe internal erosion and cavitation occurred along fibril or microfibril layers inside the fibers. Thus, the degradation of cotton by exo- and endo-type cellulases yielded quite different morphological patterns, while little difference was found for regenerated celluloses. The mode of enzymatic hydrolysis of cellulose shown by cellulases with different degrees of randomness (exo and endo types) appears to be markedly affected by the fine structure of cellulose fibers.

Antiemetic efficacy of alprazolam in the combination of metoclopramide plus methylprednisolone. Double-blind randomized crossover study in patients with cisplatin-induced emesis

The usefulness of alprazolam (minor tranquilizer) used in combination with metoclopramide plus methylprednisolone for the prevention and control of emesis induced by chemotherapies, including 5-day continuous intravenous infusion of cisplatin (25 mg/m2/day) for advanced lung cancer, was evaluated using a double-blind randomized crossover design. In our study, 34 cases could be evaluated. No nausea was observed in 14 patients given alprazolam and 4 placebo (p < .01). The mean number of vomiting episodes was significantly smaller in the alprazolam group (1.31 +/- 2.61 vs 2.89 +/- 4.59 times) (p < .01). The mean duration of nausea and vomiting was significantly shorter in the alprazolam group (p < .001 and p < .01). From these findings, it can be concluded that the coadministration of alprazolam is effective in preventing and controlling chemotherapy-induced emesis due to 5-day continuous intravenous infusion of cisplatin in which mental and psychological factors are involved.

Immunosuppressive 30-kDa protein in urine of pregnant women and patients with trophoblastic diseases

Urine samples obtained from normal pregnant women and patients with trophoblastic diseases contain 30-kDa protein that suppresses phytohemagglutinin-induced T cell proliferation. The immunosuppressive protein was measured by a newly developed radioimmunoassay. The 30-kDa protein was demonstrated in almost all urine samples examined, fluid from hydatid vesicles and chorionic extracts, but not in any serum samples except at low levels in some sera from patients with choriocarcinoma. During pregnancy, the level of urinary 30-kDa protein was higher in the first (1625.5 +/- 1212.0 ng/ml, mean +/- S.D.) and second (1457.4 +/- 1332.4 ng/ml) trimesters than in the third trimester (460.6 +/- 419.0 ng/ml). The urinary 30-kDa protein/hCG ratios in patients with choriocarcinoma (8.3 +/- 10.9) were significantly higher than those in patients with hydatidiform mole (0.67 +/- 1.00, P < 0.01) and in all trimesters than those of normal pregnant women (0.54 +/- 0.44 in first trimester, P < 0.05; 0.63 +/- 0.46 in the second trimester, P < 0.05; 0.24 +/- 0.17 in the third trimester, P < 0.01). There is no significant difference between the ratios in hydatidiform mole and normal pregnancy. These findings and the fast disappearance of the 30-kDa protein from the circulation suggest that the 30-kDa protein plays a part in proliferation of trophoblastic cells in, or their invasion into the host by locally suppressing the immune reaction of the host and that the increase in the urinary 30-kDa protein level, in cases of choriocarcinoma, may be due to the malignant transformation of trophoblastic cells resulting in their rapid invasion.

Subarachnoid fluid collection in infants complicated by subdural hematoma

In the natural history of infantile extracerebral fluid collections, subarachnoid fluid collection itself is regarded as a benign lesion, and surgical treatment is not indicated. As this condition is age-related and self-limiting, spontaneous resolution can be expected in most cases by 2-3 years of age. However, out of 20 cases of infantile subarachnoid fluid collection in an 8-year period, 3 infants developed subdural hematoma. Infantile subarachnoid fluid collection seems to be prone to complicate subdural hematoma. Surgical treatment should be considered when subarachnoid fluid collection is complicated by subdural hematoma due to arachnoid ruptures or tearing of the bridging veins. Therefore, all patients should be observed closely and measures should be taken to prevent head trauma since it may precipitate subdural hematoma.

In situ macrophage distribution in the hepatic allograft associated with rejection in the rat

The association of macrophage infiltration with orthotopic rat liver transplant rejection was studied in the ACI(RT1a) to the LEW(RT1(1)) rat combination, using immunohistochemical staining with several monoclonal antibodies at different time points. LEW recipients of ACI liver transplants experienced severe acute rejection, with a mean survival of 10.2 +/- 0.7 days. An indirect immunoperoxidase technique on cryostat sections of the liver grafts was used to determine the localization of macrophages infiltrating the grafts as defined by specific rat anti-macrophage monoclonal antibodies designated TRPM-3 and KI-M2R. In addition, the monoclonal antibodies MRC OX3 and MRC OX6 were used to detect the macrophages that expressed Ia antigens. MRC OX3 binds only with the host LEW Ia antigens, but MRC OX6 binds with both host LEW and donor ACI Ia antigens. OX3+ and OX6+ macrophages were seen in the periportal area of the hepatic allograft on Day 5; thereafter, the number of these cells increased in the periportal and pericentral areas as well as in the sinusoidal lumens. A large number of TRPM-3+ cells were also seen at the periportal area in the hepatic allograft on Day 5, whereas there was no increase in the number of KI-M2R+ cells. In addition, most of the infiltrating mononuclear cells were OX3+. These findings suggest that a large number of TRPM-3+ macrophages of recipient origin migrate into the hepatic allograft soon after transplantation. A progressive relative increase in host TRPM-3+ macrophages is a characteristic feature of ongoing first-set rejection in the rat hepatic allograft.

Effect of cyclosporine on liver regeneration after orthotopic reduced-size hepatic transplantation in the rat

These experiments were undertaken to study the effects of cyclosporine A (CsA) on liver regeneration after an isogeneic orthotopic reduced-size hepatic transplantation (RSHT) in rats. Male Wistar rats were treated with or without a daily injection of CsA beginning 24 hr before surgery and were subjected to a 68% partial hepatectomy. A isogeneic orthotopic reduced-size hepatic transplantation was performed in recipient rats pretreated with or without CsA. A daily injection of CsA was continued until the recipient rats were sacrificed. Animals were sacrificed at various time points (12, 24, 36, 48, and 72 hr) postoperatively. The incorporation of bromodeoxyuridine (BrdU) into the DNA of the remnant hepatocytes was evaluated by immunohistochemical staining with a monoclonal antibody against BrdU. CsA (10 mg/kg/day) significantly augmented BrdU incorporation into hepatocytes after hepatectomy. The maximum labeling index (LI) was observed at 24 hr after hepatectomy. In contrast, the maximum LI in the recipient rats not receiving CsA was seen at 36 hr after RSHT, and 10 mg/kg/day of CsA decreased the LI at 36 hr after RSHT. A lower dose of CsA (3 mg/kg/day), however, significantly increased the LI in the recipient rats (P < 0.01), and it reached a peak at 24 hr after RSHT when compared to the transplant recipients not receiving CsA. The time course of the increase in the LI in the transplant recipient rats receiving 3 mg/kg/day of CsA was similar to that observed in the rats after hepatectomy. This dosage improved the delay in the reduced-size hepatic transplant LI reaching its peak.(ABSTRACT TRUNCATED AT 250 WORDS)

Estrogen-inducible pS2 protein is not the key regulatory component in the proliferation of human breast cancer cells (MCF-7)

Exposure of human breast cancer cells (MCF-7) to tumor promoters such as 12-O-tetradecanoyl phorbol 13-acetate (TPA) for 24 h at concentrations of 1-100 nM resulted in marked inhibition of DNA synthesis but a 3-5-fold increase in the amount of pS2 protein in the medium. These results support our previous suggestion that pS2 protein is not involved in the mechanism controlling proliferation of MCF-7 cells. During treatment with TPA, the intracellular content of pS2 protein was constant, suggesting that TPA did not induce secretion of pS2 protein but rather de novo synthesis of the protein. The increase in the pS2 protein content of the medium by TPA was inhibited by simultaneous addition of cycloheximide, but not by that of actinomycin D. Northern-blot hybridization analysis showed that the amount of pS2 mRNA was unchanged by treatment of the cells with TPA. These results indicate that TPA does not induce transcription of the pS2 gene, and suggest that the main effect of TPA results from the induction of translation of pS2 mRNA.