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C C Capen

Publications and source records attributed to C C Capen.

At least 55 records · Page 3Linked to original sources
PubMed1996

Canine glyceraldehyde-3-phosphate dehydrogenase complementary DNA: polymerase chain reaction amplification, cloning, partial sequence analysis, and use as loading control in ribonuclease protection assays.

OBJECTIVE: To use canine glyceraldehyde-3-phosphate dehydrogenase complementary DNA (GAPDH cDNA) as a template in ribonuclease (RNase) protection assays to measure canine GAPDH mRNA expression. DESIGN AND PROCEDURE: Primers designed from the human GAPDH gene were used to amplify a 191-base pair canine GAPDH cDNA by reverse-transcription polymerase chain reaction. The cDNA was sequenced, and used as a template for RNase protection assay. SAMPLE POPULATION: Total RNA was isolated from a canine squamous carcinoma cell line. RESULTS: Canine GAPDH cDNA had a high degree of homology to human, rat, and mouse GAPDH. In vitro transcription of canine GAPDH cDNA was used to produce complementary RNA that detected canine GAPDH mRNA by RNase protection assay. CONCLUSION: Canine GAPDH cDNA is a useful loading control to be used in RNase protection assays measuring mRNA expression in canine cells or tissues.

Animals↗
PubMed1995

Sequences of the cDNAs encoding canine parathyroid hormone-related protein and parathyroid hormone.

The cDNA clones encoding canine parathyroid-hormone-related protein (cPTHrP) and parathyroid hormone (cPTH) have been isolated and sequenced. The predicted amino-acid sequences of the mature canine homologs have a high degree of homology to human PTHrP (hPTHrP) and PTH (hPTH), especially in the biologically active regions. The cPTHrP cDNA is unique, since it has homology to exon 1A of hPTHrP which suggests that dogs utilize a promoter similar to P1 of hPTHrP which has not been demonstrated in other species.

Adenocarcinoma↗
PubMed1995

Phagocytic activity of FRTL-5 rat thyroid follicular cells as measured by ingestion of fluorescent latex beads.

A rat thyroid cell line (FRTL-5) was used to study the phagocytic activity of thyroid follicular cells using fluorescent latex beads and flow cytometric analysis. Morphologic studies demonstrated that latex beads were engulfed and located within cytoplasmic vacuoles of thyrocytes. Flow cytometric evaluation of cell suspensions revealed high levels of fluorescence in cells engulfing latex beads. Using thyrotropin (TSH) as a stimulator of thyroid function and human interleukin-1 beta as an inhibitor, protocols were established for measuring the effects of these substances on either basal or TSH-induced phagocytosis. Cells exposed to latex beads over time in basal (0H) or TSH-containing medium had an increase in time-dependent phagocytic activity which was maximal after 24 or 8 h, respectively. Treatment of FRTL-5 cells with either a stimulator or an inhibitor revealed maximal change in phagocytic activity after 72 h as measured by the percentage of phagocytic cells as well as the mean fluorescence intensity. Phagocytic activity and iodide trapping by FRTL-5 cells were qualitatively similar in both sensitivity and magnitude of change in the assays used in this study. Phagocytosis of fluorescent latex beads represents a sensitive nonradioactive assay of thyrocyte function whose regulation is similar to iodide trapping.

Animals↗
PubMed1995

Mechanisms of hormone-mediated carcinogenesis of the ovary in mice.

Experimental ovarian carcinogenesis has been investigated in inbred and hybrid strains of mice and induced by a diversity of mechanisms including X-irradiation, oocytotoxic xenobiotic chemicals, ovarian grafting to ectopic or orthotopic sites, neonatal thymectomy, mutant genes reducing germ cell populations, and aging. The mechanisms are briefly reviewed whereby disruptions in the function of graafian follicles results in a spectrum of ovarian proliferative lesions including tumors. The findings in mutant mice support the concept of a secondary (hormonally-mediated) mechanism of ovarian carcinogenesis in mice associated with sterility. Multiple pathogenetic factors that either destroy or diminish the numbers of graafian follicles in the ovary result in decreased sex hormone secretion (especially estradiol-17 beta) leading to a compensatory over-production of pituitary gonadotrophins (particularly luteinizing hormone), which places the mouse ovary at an increased risk to develop tumors. The intense proliferation of ovarian surface epithelium and stromal (interstitial) cells with the development of unique tubular adenomas in response to sterility does not appear to have a counterpart in the ovaries of women.

Animals↗
PubMed1995

Ultrastructural and histomorphometric evaluations of gallium nitrate on bone in nude mice bearing a canine adenocarcinoma (CAC-8) model of humoral hypercalcemia of malignancy.

Gallium is a group IIIa transition metal that lowers serum calcium by an unknown mechanism and has been utilized in the treatment of cancer-associated hypercalcemia. The purpose of this study was to histomorphometrically investigate the ultrastructural effects of gallium nitrate on osteoclasts and osteoblasts in trabecular bone of normal nude mice and nude mice with humoral hypercalcemia of malignancy. Two groups of normal nude mice (n = 7 and n = 8, respectively) and two groups of hypercalcemic nude mice (n = 9) bearing a serially transplantable canine adenocarcinoma (CAC-8) were treated with vehicle or gallium nitrate. Osteoclasts were hypertrophied in vehicle-treated tumor-bearing nude mice as compared with vehicle-treated nontumor-bearing nude mice. Osteoclasts from tumor-bearing nude mice treated with gallium nitrate were significantly decreased in size and had fewer intracytoplasmic vesicles as compared with osteoclasts from vehicle-treated tumor-bearing nude mice. Degenerate osteoclasts, characterized by pyknotic nuclei and increased cytoplasmic vacuolation, were observed in both groups of gallium-treated nude mice. Osteoblasts from vehicle-treated tumor-bearing nude mice were hypertrophied and had extensive lamellar arrays of rough endoplasmic reticulum as compared with osteoblasts from vehicle-treated nontumor-bearing nude mice. Osteoblasts in gallium-treated nude mice (tumor-bearing and nontumor-bearing) were small and flattened with poorly developed cytoplasmic organelles. This investigation demonstrated that osteoclasts and osteoblasts in nude mice treated with gallium nitrate had ultrastructural evidence of decreased metabolic and functional activity. The results suggest that gallium nitrate lowers serum calcium by inhibiting osteoclastic bone resorption.

Adenocarcinoma↗
PubMed1995

Immunohistochemical demonstration of parathyroid hormone-related protein in thyroid gland of sheep.

Thyroid and parathyroid glands from normal adult sheep and sheep with vitamin D3-induced hypercalcemia were evaluated immunohistochemically for the presence of parathyroid hormone-related protein (PTHrP) and calcitonin (CT). Thyroid follicular cells, C-cells, and parathyroid chief cells stained moderately to strongly positive for PTHrP in both groups of sheep. C-cells were identified as cells positive for cytoplasmic staining of CT. Staining of C-cells for calcitonin in hypercalcemic sheep was diminished in intensity. The data demonstrated that PTHrP is present in the sheep thyroid and parathyroid glands. PTHrP may function as a local paracrine factor in these organs, but its staining intensity was not affected by the induction of hypercalcemia.

Animals↗
PubMed1995

Toxic effects of butylated triphenyl phosphate-based hydraulic fluid and tricresyl phosphate in female F344 rats.

Triaryl phosphates, including tricresyl phosphate (TCP and butylated triphenyl phosphates (BTP), are used in the commercial manufacture of plastics, lubricants, and hydraulic fluids. Recent reports implicate these compounds as endocrine and reproductive toxicants that can cause cholesteryl lipidosis in adrenocortical (AC) and ovarian interstitial (OI) cells, suggesting altered metabolism of steroid hormones or cholesterol or of both. We investigated potential mechanisms of BTP and TCP toxicity to determine if there were functional abnormalities of the adrenal cortex or ovary. Groups of intact (nine or 12) and ovariectomized (six) female F344 rats, 10-12 weeks of age, received 0, 0.4 g/kg TCP, or 1.7 g/kg BTP in sesame oil vehicle or 1.7 g/kg neat BTP for 20, 40, or 60 days. All rats administered BTP and TCP developed cholesteryl lipidosis in AC and OI cells; the TCP-treated group was most severely affected. Serum concentrations of androstenedione and corticosterone were unchanged, but estradiol levels were significantly (P < or = 0.05) elevated in BTP- and TCP-treated groups (14.5 times and 37.5 times greater than controls, respectively). Vaginal cytology revealed that BTP- but not TCP-treated females had abnormal reproductive cycles that were significantly prolonged in diestrus (3 times greater than control). There were significant elevations in serum total cholesterol (TCP-treated group was 1.3 times greater than controls), low-density lipoprotein (TCP-treated group was 1.8 times greater than controls), alanine transaminase (BTP-treated group was 2 times greater than controls), and albumin (a major serum estradiol-binding protein; BTP-treated group was 4.6 g/dl vs. 3.6 g/dl for controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex↗
PubMed1994

Human parathyroid hormone-related protein in ovarian small cell carcinoma. An immunohistochemical study.

BACKGROUND: Small cell carcinomas (SCC) are the most common ovarian tumors associated with hypercalcemia. Parathyroid hormone-related protein (PTHrp) is the most frequent cause of hypercalcemia of malignancy. METHODS: The presence of PTHrp in SCC has been studied by immunohistochemistry in formalin fixed, paraffin embedded tissues. A polyclonal antibody against a synthetic peptide corresponding to the first 36-N terminal amino acid residues of PTHrp was used. Normal dog skin, which is rich in PTHrp, was used as a positive control. Absorption tests using the synthetic peptide as antigen were done in all the cases. RESULTS: Immunoreactivity for PTHrp was found in five of seven cases of SCC. The serum calcium levels were elevated in two of these cases, normal in two, and unknown in one. The two negative cases were associated with high serum calcium levels. CONCLUSION: The lack of correlation between immunoreactivity and serum calcium levels can be explained on the basis that immunohistochemistry is dependent on the peptide content of cells rather than on the capability for hormone production and/or release. The results suggest that PTHrp plays a role in the development of hypercalcemia in patients with SCC of the ovary.

Adult↗
PubMed1994

Effects of gallium nitrate in nude mice bearing a canine adenocarcinoma (CAC-8) model of humoral hypercalcemia of malignancy.

Hypercalcemic nude mice bearing a canine adenocarcinoma (CAC-8) model of humoral hypercalcemia of malignancy (HHM) were treated daily with gallium nitrate (60 mg/kg of elemental gallium subcutaneously (SC) on day 0, followed by 20 mg/kg/day) for 5 days. Gallium nitrate significantly decreased (p < 0.01) serum calcium in tumor-bearing animals on days 2 and 5 of treatment (mean 13.7 +/- 0.7 mg/dl on day 0 versus 11.6 +/- 0.3 on day 2 and 12.4 +/- 0.5 on day 5). Urinary calcium excretion was decreased (p < 0.05) in the gallium-treated, tumor-bearing animals (0.11 +/- 0.01 mg calcium/mg creatinine) compared with hypercalcemic tumor-bearing mice (0.30 +/- 0.06). Both nontumor control and tumor-bearing mice treated with gallium nitrate lost body weight during the treatment period (p < 0.01). Gallium nitrate had no effect on tumor growth. Histomorphometric evaluation of lumbar vertebrae stained for tartrate-resistant acid phosphatase revealed a significant decrease (p < 0.05) in the number of osteoclasts/mm trabecular bone and perimeter of trabecular bone lined by active osteoblasts (p < 0.01) in the gallium-treated tumor-bearing mice compared with tumor-bearing controls. Osteoclast length (mm) was significantly increased in both the nontumor and tumor-bearing gallium-treated animals (p < 0.05) compared with nontumor and tumor-bearing control mice. Serum tumor necrosis factor alpha (TNF-alpha) levels were increased in tumor-bearing animals, but gallium nitrate had no effect on circulating levels (not detectable in nontumor control mice versus 82 +/- 21 pg/ml in tumor-bearing mice and 107 +/- 12 pg/ml in gallium-treated tumor-bearing mice).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1994

Reproductive toxicity of butylated triphenyl phosphate and tricresyl phosphate fluids in F344 rats.

The effects of tricresyl phosphate (TCP) and butylated triphenyl phosphate (BTP)-based hydraulic fluid on reproduction were studied in F344 rats using a modification of the National Toxicology Program's Continuous Breeding Protocol. Groups of breeding pairs received single daily oral doses of an equal volume of either 0, 0.6, 1.0 g BTP/kg or 0.4 TCP/kg in sesame oil or 1.7 g neat BTP/kg for up to 135 days. A naive control group allowed to breed, but not dosed or handled daily, demonstrated that daily dosing and handling of the rats had no effect on reproduction. The fertility index and number of litters born were significantly decreased in rats exposed to 1.0 and 1.7 g BTP/kg and 0.4 g TCP/kg. The number of pups per litter was significantly decreased in the TCP group. A crossover mating experiment using 0.4 g TCP/kg/day and 1.0 g BTP/kg/day groups, each mated with vehicle controls, demonstrated that TCP caused 100% infertility in male rats but did not affect reproduction in females. BTP caused a significant decline in reproduction in female rats characterized by low mating and fertility indices, decreased number of litters, and abnormal estrous cycles. Fertility was decreased in the BTP-dosed male rats. Both sexes of rats in the crossover experiment with TCP and BTP had significant decreases in terminal body weights and increases in adrenal gland and liver weights. Only TCP-dosed male rats had significantly decreased testicular and epididymal weights.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Parathyroid hormone-related protein in normal and neoplastic canine tissues: immunohistochemical localization and biochemical extraction.

Two polyclonal antibodies, directed against N-terminal amino acids (1-36) or the midregion (amino acids 34-53) of parathyroid hormone-related protein (PTHrP), were used to localize PTHrP in a variety of normal and neoplastic canine tissues. Parathyroid hormone (PTH) immunoreactivity was demonstrated using anti-bovine PTH (amino acids 14-34). The following tissues (among others) stained strongly positive for PTHrP: all layers of epidermal keratinocytes, with the most intense staining of the basal layer; hair follicle keratinocytes; myoepithelial cells of dermal apocrine glands, mammary glands, and apocrine glands of the anal sac; anal sac epithelium; mammary duct epithelium; and thyroid C cells. Adenocarcinomas of the anal sac stained moderately positive (5/22 dogs), weakly positive (11/22 dogs), or did not stain (6/22 dogs). Most parathyroid gland adenomas stained moderately (2/6 dogs) or weakly positive (3/6 dogs) for PTHrP. Squamous cell carcinomas (6/6 dogs) stained strongly positive. Lymphomas stained weakly positive (2/10 dogs) or did not stain (8/10 dogs). There was no consistent relationship between the staining intensity of the tumors and serum calcium concentrations of the dogs. The anti-PTH antibodies stained only parathyroid chief cells strongly positive. Concentrations of PTHrP were measured by radioimmunoassay in protein extracts from an adenocarcinoma derived from the apocrine glands of the anal sac, pancreas, kidney, liver, heart, thyroid, adrenal, and parathyroid glands. PTHrP concentrations varied from undetectable up to 150 pg/mg in normal tissues as compared with 2,000 pg/mg in apocrine adenocarcinoma of the anal sac.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Effects of humoral hypercalcemia of malignancy and gallium nitrate on thyroid C cells in nude mice: immunohistochemical and ultrastructural investigations.

Immunohistochemical and ultrastructural investigations of thyroid C cells were conducted in male nude (athymic) mice bearing a serially transplantable canine adenocarcinoma (CAC-8) model of humoral hypercalcemia of malignancy following subcutaneous administration of gallium nitrate. The following four groups were investigated: 1) vehicle-treated non-tumor-bearing control mice; 2) non-tumor-bearing mice treated with gallium nitrate; 3) vehicle-treated hypercalcemic mice bearing CAC-8; and 4) CAC-8 tumor-bearing mice treated with gallium nitrate. Gallium nitrate-treated tumor-bearing mice had a significant decrease in serum calcium as compared with tumor-bearing controls. C cells of non-tumor-bearing mice stained intensely for calcitonin and calcitonin gene-related peptide and weakly for chromogranin A and neuron-specific enolase. In C cells of both vehicle- and gallium-treated tumor-bearing mice, immunoreactive staining was decreased for calcitonin, calcitonin gene-related peptide, and chromogranin A, whereas there was a moderate increase in staining for neuron-specific enolase. Ultrastructurally, thyroid C cells in hypercalcemic tumor-bearing control and gallium-treated mice were hypertrophic and markedly degranulated as compared with those of non-tumor-bearing controls. Hypertrophic C cells contained few mature secretory granules, a well-developed Golgi apparatus, and lamellar arrays of rough endoplasmic reticulum. There was no evidence of C-cell hyperplasia. Immunohistochemical and ultrastructural findings revealed that C cells in mice with cancer-associated hypercalcemia were primarily in the actively synthesizing phase of the secretory cycle and had diminished immunoreactivity for calcitonin, calcitonin gene-related peptide, and chromogranin A.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1994

Effects of transforming growth factor-beta on parathyroid hormone-related protein production and ribonucleic acid expression by a squamous carcinoma cell line in vitro.

The effects of human recombinant transforming growth factor (TGF)-beta 1 were determined on PTH-related protein (PTHrP) production and messenger RNA (mRNA) expression by a canine squamous carcinoma cell line (SCC 2/88) in vitro. TGF-beta increased PTHrP production in a dose- and time-dependent manner (P < 0.05) as measured by RIA, and the effects of TGF-beta treatment persisted up to 72 h after removal. TGF-beta increased PTHrP production by SCC 2/88 cells until cellular confluence, at which time there was no longer a significant increase compared to control. Actinomycin D inhibited the TGF-beta-mediated increase in PTHrP production, suggesting that TGF-beta acted in part by increasing gene transcription. SCC 2/88 cells also produced active TGF-beta as measured by a [3H]thymidine incorporation assay in mink lung epithelial cells. Exposure of SCC 2/88 cells to a neutralizing anti-TGF-beta monoclonal antibody decreased (up to 50%, P < 0.01) basal PTHrP production. TGF-beta increased PTHrP mRNA expression in a dose- and time-dependent manner as evaluated by northern blot analysis. Postconfluent SCC 2/88 cells expressed little mRNA for PTHrP, and there was only a minimal increase in PTHrP mRNA expression in postconfluent TGF-beta-treated cells. These results indicate that TGF-beta increased PTHrP production and mRNA expression in malignant keratinocytes and suggest that TGF-beta may be an important factor in the pathogenesis of humoral hypercalcemia of malignancy.

Animals↗
PubMed1994

Mechanisms of chemical injury of thyroid gland.

Many goitrogenic xenobiotics that increase the incidence of thyroid tumors in rodents exert a direct effect on the thyroid gland to disrupt one of several steps in the biosynthesis and secretion of thyroid hormones. This includes 1) inhibition of the iodine-trapping mechanism (thiocyanate or perchlorate), 2) blockage of organic binding of iodine and coupling of iodothyronines to form thyroxine (T4) and triiodothyronine (T3) (e.g., sulfonamides, thiourea, methimazole, and aminotriazole, among others), and 3) inhibition of thyroid hormone secretion by an effect on proteolysis of active hormone from the colloid (lithium or an excess of iodide). Another large group of goitrogenic chemicals disrupts thyroid hormone economy by increasing the peripheral metabolism of thyroid hormones through an induction of hepatic microsomal enzymes. This group includes CNS-acting drugs (phenobarbital, benzodiazepines), calcium channel blockers (nicardipine, nifedipine), steroids (spironolactone), retinoids, chlorinated hydrocarbons (chlordane, DDT, TCDD), polyhalogenated biphenyls (PCB, PBB), and enzyme inducers. Thyroid hormone economy also can be disrupted by xenobiotics that inhibit the 5'monodeiodinase, which converts T4 in peripheral sites (e.g., liver and kidney) to biologically active T3. Inhibition of this enzyme by FD&C Red No. 3, amiodarone, and iopanoic acid lowers circulating T3 levels, which results in a compensatory increased secretion of thyroid-stimulating hormone (TSH), follicular cell hypertrophy and hyperplasia, and an increased incidence of follicular cell tumors in 2-year or lifetime studies in rats. Physiologic perturbations alone such as the feeding of an iodine-deficient diet, partial thyroidectomy, natural goitrogens in certain foods, and transplantation of TSH-secreting pituitary tumors in rodents also can disrupt thyroid hormone economy and, if sustained, increase the development of thyroid tumors in rats. A consistent finding with all of these goitrogens, be they either physiologic perturbations or xenobiotic chemicals, is the chronic hypersecretion of TSH, which by receptor-mediated events places the rodent thyroid gland at greater risk of developing tumors through a secondary mechanism of thyroid oncogenesis.

Animals↗
PubMed1993

Parathyroid hormone-related protein production by normal human keratinocytes in vitro.

The role of parathyroid hormone-related protein (PTHrP) and its regulation in normal epidermal physiology is not currently known. Recent evidence suggests that PTHrP production may be related to the degree of differentiation of keratinocytes in vitro. This investigation characterized the production of PTHrP by normal human foreskin keratinocytes (NHFK) during both spontaneously occurring and induced differentiation in vitro. PTHrP production in keratinocyte serum-free conditioned medium was determined using an N-terminal radioimmunoassay for human PTHrP (1-36). Agents known to stimulate (calcium, 1,25-dihydroxyvitamin D3) or inhibit (transforming growth factor-beta) keratinocyte differentiation were examined for their ability to alter production of PTHrP. Measurements of cell number and involucrin content of the cultures were made to confirm the effects of these agents on keratinocyte growth and differentiation. The production of PTHrP in control cultures (under low calcium conditions, 0.08 mM) was decreased and involucrin content increased (P < 0.01) after the cells became confluent. The addition of 1 mM calcium to keratinocyte medium increased cell number and involucrin content of the cultures (P < 0.05) but inhibited production of PTHrP (P < 0.01). The 1,25-dihydroxyvitamin D3 (10 nM) had no significant effect on cell number or PTHrP production, but increased involucrin content (P < 0.05). Transforming growth factor-beta (5 ng/ml) decreased both cell number (P < 0.05) and involucrin content (P < 0.01), but significantly stimulated PTHrP production (P < 0.01). These data indicate that the production of PTHrP by NHFK is inhibited with the onset of both spontaneously occurring and calcium-induced differentiation in vitro, while transforming growth factor-beta inhibited differentiation and upregulated PTHrP production in normal human keratinocytes.

Calcitriol↗
PubMed1993

Pathogenesis of cholesteryl lipidosis of adrenocortical and ovarian interstitial cells in F344 rats caused by tricresyl phosphate and butylated triphenyl phosphate.

Triaryl phosphates including tricresyl phosphate (TCP) and butylated triphenyl phosphate (BTP) are organophosphates used in the commercial manufacture of plastics, lubricants, and hydraulic fluids. Rat steroidogenic tissues such as adrenocortical (AC), ovarian interstitial (OI), and Leydig cells use an intracellular pathway to store cholesterol (substrate for biosynthesis of steroid hormones) as cholesteryl ester (CE). This pathway and the pathway for uptake of serum cholesterol are less used in Leydig cells of the adult male rat, resulting in a lower CE pool. BTP and TCP caused cholesteryl lipidosis in steroid hormone-synthesizing AC and OI, but not Leydig cells in the adult rat. The objectives of this study were to determine if the administration of triaryl phosphate fluids caused a defect in the cholesterol storage pathway of AC and OI cells and to determine the mechanism of action. Female rats received daily oral doses of 0 or 0.4 g/kg TCP in sesame oil vehicle or 1.7 g/kg neat BTP for 40 days. Adrenal glands from both treatment groups and ovaries from TCP-treated rats were heavier than controls. Microscopic and biochemical studies revealed cholesteryl lipidosis composed of CE in the adrenal glands and ovaries in BTP- and TCP-treated rats with the latter group affected most severely. The activity of neutral CE hydrolase (nCEH), an enzyme that converts CE to cholesterol in the uptake and storage pathways, also was inhibited most in the TCP-treated group (97% inhibition compared to that of control). The activity of acyl coenzyme A:cholesterol acyl transferase, an enzyme that esterifies cholesterol to make CE, was depressed 27% compared to that of control adrenal glands of the TCP group, resulting in elevated intracellular cholesterol levels in AC cells. An inhibition of nCEH in the storage and uptake pathways by triaryl phosphates most likely resulted in the striking accumulation of CE in cytoplasmic lipid droplets of AC and OI cells in F344 rats.

Adrenal Cortex Diseases↗
PubMed1993

Effects of hormones and cytokines on stimulation of adenylate cyclase and intracellular calcium concentration in human and canine periodontal-ligament fibroblasts.

Adenylate cyclase was stimulated by prostaglandin E2 (PGE2) and parathyroid hormone-related protein (PTHrP) in both these types of fibroblast and by calcitonin gene-related protein (CGRP) in the human fibroblasts in vitro. PGE2 (1 microM), CGRP (1 microM), and PTHrP (1 microM) stimulated adenylate cyclase up to 50-fold, 10-fold and 9-fold, respectively. Calcitonin (CT), substance P (SP), interleukin-1 beta (IL-1 beta), and transforming growth factor-beta 1 (TGF beta 1) had no effect on adenylate cyclase in either fibroblast. Intracellular Ca2+ (iCa2+) was measured in individual fibroblasts from the periodontal ligament using Indo-1 and an adherent cell analysis and sorting interactive laser cytometer. Ionomycin (3 microM) caused a transient rise of iCa2+ in all human and canine fibroblasts tested. The mean percentage increase in iCa2+ in response to ionomycin was 820 and 840% for human and canine fibroblasts, respectively. The human fibroblasts responded to PGE2 (1 microM) by an increased iCa2+ concentration; the mean percentage increase in iCa2+ was 187%. SP caused a less pronounced increase in iCa2+ in the human fibroblasts (56%). CGRP and SP caused a similar response in the canine fibroblasts. The mean percentage increase in iCa2+ in response to SP and CGRP was 95 and 78%, respectively. PTH, PTHrP, platelet-activating factor, CT, and IL-1 beta had no effect on iCa2+ in either type of fibroblast. The data indicate that cAMP and calcium have roles as intracellular secondary messengers in the action of PGE2, SP, CGRP, and PTHrP in fibroblasts of human and canine periodontal ligament.

Adenylyl Cyclases↗