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PubMed1994

Atrial natriuretic peptide in the Milan hypertensive rat and the Milan normotensive rat: plasma concentration and binding to renal glomeruli in young, adult and aged rats.

METHODS: Blood pressures were determined in Milan hypertensive (MHS) and Milan normotensive (MNS) rats at different ages. Mean blood pressure, plasma atrial natriuretic peptide (ANP) concentration and renal glomerular receptors numbers and affinities were determined in young (25-day-old), adult (60- to 80-day-old) and aged (300-day-old) rats. RESULTS: Mean blood pressures, always higher in the MHS than in the MNS rats, increased with age in both strains. Plasma ANP concentrations were similar in the young and aged rats of both strains, but were higher in the adult MHS than in the adult MNS rats. There were no quantitative differences in the ANP receptors between young and old rats of the two strains, but an increase in the maximal binding capacity was observed, in both strains, when adult rats were compared with young rats. Moreover, saturation experiments with [125I]-rat ANP revealed a downregulation of the ANP receptors in the renal glomeruli isolated from the adult MHS rats. In isolated glomeruli the cyclic GMP stimulation by ANP was similar in adult rats of both strains. CONCLUSION: Downregulation in glomeruli of MHS rats, probably involving the clearance receptors for ANP, is concluded to occur.

Aging↗
PubMed2002

Long-Evans rats have a larger cortical topographic representation of movement than Fischer-344 rats: a microstimulation study of motor cortex in naïve and skilled reaching-trained rats.

Intracortical microstimulation of the frontal cortex evokes movements in the contralateral limbs, paws, and digits of placental mammals including the laboratory rat. The topographic representation of movement in the rat consists of a rostral forelimb area (RFA), a caudal forelimb area (CFA), and a hind limb area (HLA). The size of these representations can vary between individual animals and the proportional representation of the body parts within regions can also change as a function of experience. To date, there have been no investigations of strain differences in the cortical map of rats, and this was the objective of the present investigation. The effect of cortical stimulation was compared in young male Long-Evans rats and Fischer-344 rats. The overall size of the motor cortex representation was greater in Long-Evans rats compared to Fischer-344 rats and the threshold required to elicit a movement was higher in the Fischer-344 rats. An additional set of animals were trained in a skilled reaching task to rule out the possibility that experiential differences in the groups could account for the result and to examine the relationship between the differences in topography of cortical movement representations and motor performance. The Long-Evans rats were quantitatively and qualitatively better in skilled reaching than the Fischer-344 rats. Also, Long-Evans rats exhibited a relatively larger area of the topographic representation and lower thresholds for eliciting movement in the contralateral forelimb. This is the first study to describe pronounced strain-related differences in the microstimulation-topographic map of the motor cortex. The results are discussed in relation to using strain differences as a way of examining the behavioral, the physiological, and the anatomical organization of the motor system.

Animals↗
PubMed2006

Introgression of F344 rat genomic DNA on BB rat chromosome 4 generates diabetes-resistant lymphopenic BB rats.

Failure to express the Gimap5 protein is associated with lymphopenia (lyp) and linked to spontaneous diabetes in the diabetes-prone BioBreeding (BBDP) rat. Gimap5 is a member of seven related genes located within 150 Kb on rat chromosome 4. Congenic DR.(lyp/lyp) rats, where BBDP lyp was introgressed onto the diabetes-resistant BBDR background (BBDR.BBDP.(lyp/lyp)), all develop diabetes between 46 and 81 days of age (mean +/- SE, 61 +/- 1), whereas DR.(lyp/+) and DR.(+/+) rats are nonlymphopenic and diabetes resistant. In an intercross between F1(BBDP x F344) rats, we identified a rat with a recombination event on chromosome 4, allowing us to fix 33 Mb of F344 between D4Rat253 and D4Rhw6 in the congenic DR.lyp rat line. Gimap1 and Gimap5 were the only members of the Gimap family remaining homozygous for the BBDP allele. Offspring homozygous for the F344 allele (f/f) between D4Rat253 and D4Rhw6 were lymphopenic (85 of 85, 100%) but did not develop diabetes (0 of 85). During rescue of the recombination, 102 of 163 (63%) rats heterozygous (b/f) for the recombination developed diabetes between 52 and 222 days of age (88 +/- 3). Our data demonstrate that introgression of a 33-Mb region of the F344 genome, proximal to the mutated Gimap5 gene, renders the rat diabetes resistant despite being lymphopenic. Spontaneous diabetes in the BB rat may therefore be controlled, in part, by a diabetogenic factor(s), perhaps unrelated to the Gimap5 mutation on rat chromosome 4.

Animals↗
PubMed1999

Hepatic cytochrome P450 and flavin-containing monooxygenase in male Nts:Mini rat, a transgenic rat carrying antisense RNA transgene for rat growth hormone.

We investigated the characteristics of hepatic cytochrome P450s and flavin-containing monooxygenase 1 (FMO1) in male Nts:Mini rats, a Wistar/Jcl-derived transgenic rat strain showing less plasma GH concentration than the parental strain. The total hepatic P450 contents of Mini rats were significantly reduced. A suppression was observed in the activities and protein expression of male-specific P450s (CYP3A and CYP2C11) and was speculated to be a potential cause of the reduction in total P450 contents. The activity and protein expression of CYP2B1 were suppressed and those of CYP2E1 and CYP2B2 were enhanced. With the exception of our data on CYP2B1, these results largely agreed with previous reports concerning GH-depletion rat models (hypophysectomized rats, rats neonatally treated with glutamate, and dwarf rats), implying that the changes in Mini rats were caused by GH insufficiency. The liver FMO1 protein expression in Mini rats was higher than that in Wistar rats but the activity was comparable, suggesting that GH is not a positive regulator of FMO expression. With their insufficient but not depleted levels of plasma GH, Mini rats may thus become another candidate for use in the investigation of GH regulation of hepatic mixed-function monooxygenases.

Animals↗
PubMed2002

Involvement of 5-hydroxytryptamine(1A) receptors in the descending anti-nociceptive pathway from periaqueductal gray to the spinal dorsal horn in intact rats, rats with nerve injury and rats with inflammation.

Studies have shown that 5-hydroxytryptamine (5-HT) plays an important role in the descending pathway of pain modulation from brainstem to the spinal cord. Using selective 5-HT receptor antagonists, the present study investigated which type of 5-HT receptor(s) in the spinal cord was involved in the morphine-induced anti-nociception in intact rats, in rats with nerve injury and in rats with inflammation. The hindpaw withdrawal latencies decreased significantly after sciatic nerve injury and hindpaw inflammation compared with intact rats. Intrathecal administration of 25 or 10 microg of the selective 5-HT(1A) recepter antagonist spiroxatrine, but not 1 microg of spiroxatrine, significantly blocked the increased hindpaw withdrawal latencies to thermal and mechanical stimulation induced by intra-periaqueductal gray injection of 1 microg of morphine in intact rats. Intrathecal injection of the 5-HT(2) receptor antagonist RS 102221 and the 5-HT(3) receptor antagonist MDL 72222 had no significant effects on the increased hindpaw withdrawal latencies to both noxious stimulations induced by intra-periaqueductal gray injection of morphine. Furthermore, intrathecal administration of spiroxatrine, but not RS 102221 nor MDL 72222, significantly attenuated the increased hindpaw withdrawal latencies induced by intra-periaqueductal gray administration of morphine in rats with nerve injury and in rats with inflammation. The results demonstrate that the 5-HT(1A) receptor, not 5-HT(2) nor 5-HT(3) receptor, plays an important role in the descending pathway of anti-nociception from the brainstem to the spinal cord in intact rats, in rats with nerve injury and in rats with inflammation.

Analgesics, Opioid↗
PubMedDate not supplied

Inhibitory action of rat insulin and synthetic rat C-peptide on insulin secretion in the perfused rat pancreas.

In order to determine whether both insulin and C-peptide have an inhibitory action on insulin secretion, the isolated rat pancreas was perfused with exogenous rat insulin or synthetic rat C-peptide in the presence of high or low concentration of glucose. In the presence of 2.8 mM glucose, exogenous rat insulin (4 or 10 ng/ml) and C-peptide 1 and 2 (100 ng/ml) show no effect on the insulin levels in the outflow from the perfused pancreas. However, the insulin response to 16.7 mM glucose decreased in the presence of exogenous rat insulin or synthetic rat C-peptide, showing a biphasic pattern of glucose-induced insulin release. When rat insulin or C-peptide were added at 20 min and removed at 40 min while the isolated pancreas was exposed to a 60-min glucose infusion (16.7 mM), glucose-induced insulin secretion decreased during the infusion of rat insulin or C-peptide. The present study clearly showed that exogenous rat insulin and synthetic rat C-peptide 1 and 2 inhibited glucose-induced insulin secretion. Although the suppressive mechanisms of the exogenous insulin and the C-peptide on insulin release are not yet proved, the inhibitory process is considered to be related to cyclic AMP in the pancreatic B-cell.

Animals↗
PubMedDate not supplied

Conservation analysis of rat and human SP-A gene identifies 5' flanking sequences of rat SP-A that bind rat lung nuclear proteins.

As an initial step toward understanding regulation of tissue-specific expression of SP-A, 5' flanking sequences of the rat SP-A gene and human SP-A I gene were cloned, sequenced, and compared using dot matrix analysis. Two regions were identified, each with a considerable degree of homology between the two species. One region was proximal to the TATAA box, at position -225/-17 in rats and -226/-36 in humans, and the other at position -1115/-1026 in rats and -938/-851 in humans. Studies in rats revealed the specific binding of rat lung nuclear proteins to each of the conserved 5' flanking regions identified in rat SP-A. Binding studies using the rat proximal (rPPS) or distal (rDPS) promoter segments, or overlapping fragments of these segments, with rat nuclear extracts detected the presence of a number (1-4) of lung-specific DNA/protein complexes. When nuclear proteins from liver, a nonexpressing tissue, were used the binding profile of certain nuclear proteins differed from that of the lung. These studies, taken together, suggest that sequences within identified conserved DNA segments in the 5' flanking region of the rat SP-A gene contribute to its tissue-specific expression in rats.

Animals↗
PubMed1992

Experimental Yersinia enterocolitica infection in rats: analysis of the immune response to plasmid-encoded antigens of arthritis-susceptible Lewis rats and arthritis-resistant Fischer rats.

Recently, experimentally Yersinia-induced arthritis in Lewis and SHR rats has been described as a potential animal model for analyzing the pathomechanism of reactive arthritis (Toivanen et al. 1986; Hill and Yu 1987). We could confirm that Lewis but not Fischer rats develop aseptic arthritis about 2 weeks after an intravenous inoculation of Yersinia enterocolitica, serotype 0:8 (Hill and Yu 1987). Moreover, we compared the antibody response to virulence-associated Yersinia antigens (Yops) of experimentally infected Lewis rats with that of Fischer rats using an enzyme-linked immunosorbent assay (ELISA) and immunoblotting. The ELISA results revealed a more rapid and vigorous specific IgG, IgA and IgM response for Lewis rats than for Fischer rats in the early state of infection. As demonstrated by immunoblotting, the IgG response was directed predominantly against the plasmid-encoded YopM, YopH, YopD and the V-antigen during the acute phase followed by antibodies against YopE and YadA. Although both rat strains seroconverted against this set of antigens, IgG antibodies to YadA were more prevalent and of higher titer in arthritis-susceptible rats compared to arthritis-resistant rats.

Animals↗
PubMed2002

Decreased susceptibility to NMU-induced mammary carcinogenesis in transgenic rats carrying multiple copies of a rat ras gene driven by the rat Harvey ras promoter.

Ras protein over-expression has been observed in human breast cancers although the significance of Ras over-expression in the etiology of breast cancer is unknown and its contribution to breast cancer prognosis is still debated. In this study, the over-expression of both wild-type Harvey and Kirsten Ras proteins as contributors to rat mammary carcinogenesis were examined using a transgenic rat model. Three rat transgenic lines (designated HrHr transgenics) carrying three to six copies of wild-type rat Harvey ras driven by the wild-type rat Harvey ras promoter were produced. In addition, transgenic lines carrying either three or seven copies of the Kirsten ras gene under the same promoter (HrKr) were produced. No pathological changes in the mammary gland were observed in any of the HrHr or HrKr transgenic rat line heterozygotes. Two of the Ras transgenic lines, HrHr (R8) and HrKr (4334), had a significant reduction in NMU-induced rat mammary cancer when compared to their non-transgenic littermates. All five Ras transgenic lines developed fewer carcinomas than their non-transgenic littermates following NMU exposure. The percentage of NMU-induced G35 to A35 activating mutations in the endogenous Harvey ras gene in mammary carcinomas from the HrHr, HrKr transgenic rats and their non-transgenic littermates was similar ( approximately 50%). In contrast, less than 1% of the NMU-induced carcinomas in these Ras transgenic rats had an activating ras mutation in their transgenes. These findings highlight the potential of Ras to function as a modifier gene in repressing mammary carcinogenesis.

Animals↗
PubMed2006

Effects of dietary oyster extract on lipid metabolism, blood pressure, and blood glucose in SD rats, hypertensive rats, and diabetic rats.

Oyster extract was prepared by hydrolysis of oyster protein with proteases, Aloase (a protease from Bacillus subtilis), and Pancitase (a protease from Aspergillus oryzae). Rats were fed a diet containing 20% casein (the control diet) or 15% casein and 5% oyster extract (the oyster extract diet) as the protein source. The oyster extract diet exerted a significant reduction in serum cholesterol and liver triglyceride concentrations as compared with the control diet in Sprague-Dawley (SD) rats fed cholesterol-supplemented diets for 4 weeks. The activities of cytosolic fatty acid synthase and glucose-6-phosphate dehydrogenase were significantly lower in the oyster extract group than in the control group in the liver of SD rats. Hepatic cholesterol and triglyceride concentrations were significantly lower in spontaneously hypertensive (SH) rats and Otsuka Long-Evans Tokushima Fatty (OLETF) rats, type 2 diabetic rats, fed the oyster extract diet, for 4 weeks and 4 months respectively, than in those fed the control diet in the cholesterol-free diet. Blood pressure was significantly lower in the oyster extract group than in the control group at the 2nd and 4th weeks after the beginning of feeding experimental diets in SH rats. These results suggest that oyster extract prepared by hydrolysis of oyster induces triglyceride-lowering activity in the liver through a decrease in hepatic lipogenesis in SD rats, and that it exerts the antihypertensive effect in SH rats.

Animals↗
PubMed1961

Antigenicity of rat collagen. Demonstration of antibody to rat collagen in the renal glomeruli of rats by fluorescence microscopy.

Rabbit serum or globulin, containing antibody to rat collagen, injected intravenously or intracardially into normal or adjuvant-prepared rats becomes fixed in the basement membranes of renal glomeruli and, to a slight extent, of the tubules. When examined by ultraviolet light, this antibody can be identified in tissue sections by the yellow-green fluorescence occurring where the rabbit globulin, associated with the fixed collagen antibody, has reacted with fluorescein-conjugated anti-rabbit globulin from ducks. The reaction of the antibody to rat collagen with its antigen in the kidney is a primary factor in the production of the renal glomerular injury which occurs in rats prepared with adjuvant. Adjacent control sections failed to fluoresce when pretreated with unlabeled anti-rabbit globulin or when treated with heterologous conjugated anti-duck globulin from rabbits. The antibody to rat collagen remains in the kidney as long as 92 days and has been detected as early as 45 minutes after injection. When normal rabbit serum, rabbit anti-fish collagen serum, or rabbit anti-rat collagen serum absorbed with rat collagen was substituted for the rabbit anti-rat collagen serum, fixed antibody could not be demonstrated by fluorescence; but absorption of the anti-rat collagen serum with fish collagen did not affect the antibody fixation. This series of immunologic tests indicates that the anti-collagen serum reacts with its homologous antigen, presumably collagen, in the basement membranes of renal glomeruli and tubules, and that specific antibody can be used to identify collagen in other tissues of the animal body.

Animals↗
PubMed1971

Aortic reactivity and electrophysiology in normotensive rats, spontaneously hypertensive rats and rats made hypertensive with desoxycorticosterone plus salt.

The mechanical and electrophysiological activity of rings and strips of thoracic aortic smooth muscle taken from normotensive, DOCA-hypertensive and New Zealand spontaneously hypertensive (A.S. strain) rats have been compared. Aortae from A.S.-hypertensive rats developed less tension in the presence of noradrenaline and K+ than those isolated from normotensive and DOCA-hypertensive rats. Aortae from DOCA-hypertensive rats developed the same tension in response to K+ as normotensive rats but were less reactive to noradrenaline. Measurements of resting membrane potentials from the three groups of rats demonstrated that whereas normotensive and DOCA-hypertensive rats had similar resting membrane potentials, those from A.S.-hypertensive rats were significantly lower (P<0.001). It is suggested that the enhanced responsiveness of intact vascular beds in A.S.-hypertensive rats is a consequence of a change in the geometry of the blood vessels rather than an increase in the contractor response of the smooth muscle cells.

Animals↗
PubMed2000

Radiographic analysis of the development of periapical lesions in normal rats, sialoadenectomized rats and sialoadenectomized-immunosuppressed rats.

The purpose of this study was to investigate and to compare radiographically the development of periapical lesions in the lower left first molar of normal rats, sialoadenectomised rats and sialoadenectomised-immunosuppressed rats. Sixty male Wistar rats, weighing from 170 to 200 g were utilized. The animals were divided equally into three groups: group I--20 normal rats; group II--20 sialoadenectomised rats; and group III--20 sialoadenectomised-immunosuppressed rats. Groups II and III were sialoadenectomized using the modified Cheyne technique. After 2 weeks, group III was submitted to a immunosuppression regimen by daily subcutaneous cyclosporin A injection (10 mg/kg body weight). After 1 week of immunosuppression for this group, the pulps of all the animals (group I, II and III) were exposed to the oral cavity, to produce apical periodontitis. Five animals of each group were killed 7, 14, 21 and 28 days after pulpal exposure. Their mandibles were surgically removed and radiographically analysed. The lesions were measured using 'Global Lab Image' software. The results showed predictable growth of the lesions during the experimental period. No significant difference was observed between the groups. It was concluded that possible changes in the oral flora and in the host immune response due to xerostomia associated or not to the immunosuppression did not alter the development of the periapical lesions in rats.

Animals↗
PubMedDate not supplied

Effects of rat interleukin-2 and rat interferon on the natural killer cell activity of rat spleen cells after thermal injury.

The natural killer cell activity of splenocytes from rats with scald injury was observed to be significantly suppressed at 7 days after injury compared with that of normal nonburned controls. Incubation of splenocytes from normal rats or rats with burn injury with either rat interleukin-2 or rat interferon (IFN-alpha and IFN-beta) significantly increased the natural killer cell activity. Addition of a rabbit anti-rat interferon antibody to spleen cells incubated with interleukin-2 did not produce any significant alteration in interleukin-2-related enhancement of natural killer cell activity. These results suggest that enhancement of natural killer cell activity after incubation of splenocytes with interleukin-2 is not due to interferon production but is an independent event. Preincubation of spleen cells with a mouse monoclonal antibody to rat interleukin-2 receptor was observed to abolish the interleukin-2-related enhancement of natural killer cell activity completely, whereas it partially blocked the interferon-related enhancement. These results were also confirmed by enhancement of natural killer cell activity of burned rats after in vivo administration of interleukin-2. Our studies thus indicate that after thermal injury, the observed decrease of natural killer cell activity can be enhanced by both interleukin-2 and interferon independently of each other. The decreased natural killer cell activity may be due to a decrease in interleukin-2 production or availability and not to an interleukin-2 receptor defect. These studies thus point toward a potential therapeutic significance of interleukin-2 in enhancing immune function after thermal injury.

Animals↗
PubMed2004

Inhibition by allyl sulfides and phenethyl isothiocyanate of methyl-n-pentylnitrosamine depentylation by rat esophageal microsomes, human and rat CYP2E1, and Rat CYP2A3.

Garlic and Cruciferae are associated with reduced risks of several human cancers, and some of their constituents are anticarcinogenic in animals. Here we studied inhibition of in vitro metabolism of the rat esophageal carcinogen methyl-n-pentylnitrosamine (MPN) by garlic-derived allyl sulfides and by Cruciferae-derived phenethyl isothiocyanate (PEITC) and sulforaphane. The test inhibitors were incubated with [3H]-MPN, NADPH-generating system and rat esophageal microsomes (REM) or a cytochrome P450 (CYP). [3H]-MPN activation by depentylation was assayed by HPLC with radiometric determination of [3H]-pentaldehyde 2,4-dinitrophenylhydrazone. IC50 for depentylation of 40 microM MPN by rat CYP2E1 was 5-12 microM for diallyl sulfide (DAS), diallyl disulfide (DADS), and PEITC and 10-20 microM for diallyl sulfone, allyl mercaptan, and diallyl trisulfide. Maximum inhibition required preincubation of rat CYP2E1 with DAS for 15 min and with DADS for 30 min. Using these preincubation times, Ki for MPN depentylation by REM, rat and human CYP2E1, and rat CYP2A3 was 0.6-1.6 microM for inhibition by DAS and 1.7-70 microM for inhibition by DADS. With PEITC, Ki for MPN depentylation by REM, rat CYP2E1, and rat CYP2A3 was 0.4-4.6 microM. These low Ki and IC50 values may help explain how garlic and Cruciferae inhibit carcinogenesis.

Allyl Compounds↗
PubMed1997

Central lactogenic regulation of maternal behavior in rats: steroid dependence, hormone specificity, and behavioral potencies of rat prolactin and rat placental lactogen I.

Adult virgin female rats display maternal behavior when continuously exposed to foster young for 5-6 days. Central infusions of PRL or placental lactogens (PLs) together with systemic treatment of progesterone (P) and estradiol (E2) stimulate maternal behavior in 1-2 days. In the present set of studies, it was asked whether the actions of lactogenic hormones are dependent upon both E2 and P and specific to lactogenic molecules. Moreover, we wanted to know whether central infusions of rat (r) PRL and PLs were equally effective in inducing maternal behavior. In the first study, adult virgin rats were ovariectomized (ovx) and stereotaxically fitted with bilateral cannulas directed at the medial preoptic area (MPOA). Rats were then assigned to one of four groups: P plus E2, blank (B) plus E2, P plus B, and B plus B. P-filled or B capsules were implanted sc on treatment day 1 and removed on day 11, whereas E2 or B capsules were implanted on day 11. All groups were infused with rPRL (40 ng/side) five times from days 11-13 and injected with bromocriptine (CB-154) sc (days 11-17) to suppress endogenous PRL release. Behavioral testing was conducted daily from days 12-17. It was found that exposure to both P and E2 was necessary to induce a fast onset of maternal behavior in PRL-infused females; priming with P or E2 alone in PRL-treated rats failed to stimulate a fast onset of behavior relative to that in nonsteroid-treated controls. In the second experiment to determine the biochemical specificity of PRL's action, adult nulliparous rats were ovx, implanted with bilateral cannulas directed at the MPOA, treated with both P and E2, injected with CB-154, and infused centrally (five times) with 40 ng (per side) of bovine GH, ovine LH, or vehicle. Central infusions of either bovine GH or ovine LH failed to stimulate maternal behavior, suggesting that the stimulatory actions of PRL are related to its lactogenic properties. In the final study, rats were ovx, fitted with bilateral cannulas directed at the MPOA; treated with P, E2, and CB-154; and given a single set of bilateral infusions of rPL-I or rPRL (40 ng/side.infusion) on day 11, three sets of infusions of rPL-I or rPRL (days 11 and 12), or vehicle infusions. Rats given three infusions of rPL-I and rPRL responded faster than controls, although the effect was not as robust as that in animals given five infusions in the initial study. rPL-I and rPRL groups did not differ from one another. Together these studies indicate that 1) both P and E2 are required for lactogenic stimulation of maternal behavior; 2) the stimulatory actions of PRL and rPLs on maternal behavior are related to their lactogenic properties; 3) extended treatment of females with lactogenic hormones is more effective in stimulating the onset of maternal behavior; and 4) the neural potencies of rPRL and rPL-I are similar. These findings provide support for the idea that the induction of maternal behavior is stimulated by the central actions of lactogenic hormones.

Animals↗
PubMed1962

Antigenicity of rat collagen. Distribution of antibody to rat collagen injected into rats.

Antibody to rat collagen, prepared in rabbits and injected into the circulation of normal or adjuvant-prepared rats, becomes fixed to its antigen and can then be identified in tissue sections under ultraviolet light by its fluorescence after application of fluorescein-conjugated anti-rabbit globulin. In heart, lung, liver, spleen, adrenal, kidney, jejunum, lymph node, thymus, joint synovia, peripheral nerve, aorta, skeletal muscle, eye, and brain, the antibody was found at all sites where collagen and reticulin are normally present, but except for the kidneys of the adjuvant-prepared rats, no pathological abnormalities were demonstrated. It was not found within cells. Specific fluorescence was absent from tissues of rats injected with normal rabbit serum or rabbit anti-fish collagen serum or rabbit anti-rat collagen serum after absorption with rat collagen, but was present when the anti-rat collagen serum had been absorbed with fish collagen. The reaction could be blocked by pretreatment of sections with unlabeled anti-rabbit globulin and did not occur with heterologous labeled anti-duck globulin. After serial treatment in vitro with homologous antibody to collagen and the conjugated anti-rabbit globulin, purified reconstituted collagen fibers showed the same fluorescence as fibers in the tissues; no fluorescence of the fibers occurred when heterologous antibody to collagen was applied. These findings indicate that the antibody to rat collagen is directed toward an antigen present in both collagen and reticulin.

Animals↗