Biopsia tiroidea por punción: experiencia en 850 casos / Needle biopsy of the thyroid: experience in 850 cases

Se analizan 850 biopsias tiroideas por punción con aguja Tru-cut, producto de mi experiencia personal desde 1973-91 (18 años), realizadas en los Hospitales Universitario y F.A. Rísquez de Caracas y en la Clínica Luis Razetti. Predominó el sexo femenino con 820 (96%) y 30 (4%) hombres, en edades comprendidas entre los 10 y 75 años. La correlación entre biopsia por punción con Tru-cut y la biopsia de la pieza quirúrgica en 364 operados fue la siguiente: 45 pacientes con Graves-Basedow se operaron y 42 correspondieron (93%) y 3 (7%) fueron tiroiditis linfocitarias; 20 pacientes con bocios coloides se operaron 20 y 15 (75%) correspondieron, y 5 (25%) fueron bocios adenomatosos: 140 casos con bocios adenomatosos se operaron 130 pacientes correspondieron (93%), 5 (3%) fueron carcinoma y 5 (3%), tiroiditis crónicas; de 150 nódulos operados 116 (77%) correspondieron (77%) como adenomas y quistes, 20 casos (13%) fueron bocios adenomatosos y 14 (9%) carcinomas. De los 9 carcinomas operados se correspondieron todos por ser lesiones avanzadas. Hubo un total de 28 carcinomas (8%) de todos los operados. La biopsia se hace ambulatoria con complicaciones mínimas, con un 94% de muestras adecuadas y 6% de muestras inadecuadas

Molecular heterogeneity of the subclasses of islet-activating protein (pertussis toxin)-sensitive GTP-binding proteins in porcine thyroid tissue.

From porcine thyroid cell membranes, we purified five GTP-binding proteins (G-proteins); Nos. 1 to 3 have 41-kDa alpha-subunits, and Nos. 4 and 5 have 40-kDa alpha-subunits. They were chromatographically (Mono Q) separable and served as specific substrates for islet-activating protein (pertussis toxin). G-proteins 1 and 2 were indistinguishable from porcine brain Gi1 with respect to three criteria, i.e., mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pI of the ADP-ribosylated alpha-subunit, and immunoreactivity. G-protein 3 was identified as Gi3 by immunoreactivity. The SDS-PAGE and isoelectric focusing (IEF) analyses identified G-proteins 4 and 5 as being chromatographically heterogeneous subtypes of Gi2 in comparison with a pure porcine brain preparation. The IEF analysis also disclosed that each of the Gi1, Gi2, and Gi3 subspecies isolated in the present study has a minor component characterized by a slightly lower pI of its alpha-subunit. We conclude that porcine thyroid tissue contains at least Gi1, Gi2, and Gi3, and that each is made up of heterogeneous populations.

Characterization of site-specific polyclonal antibodies to c-erbA peptides recognizing human thyroid hormone receptors alpha 1, alpha 2, and beta and native 3,5,3'-triiodothyronine receptor, and study of tissue distribution of the antigen.

The translated products of v-erbA-related cDNAs have been demonstrated to be thyroid hormone receptors, and three different forms of receptor (alpha 1, alpha 2, and beta) have been found in human tissues. We synthesized five peptides corresponding to different portions of these three receptors and raised site-specific polyclonal-antipeptide sera in rabbits. Each antibody displayed high titer and specificity for its respective antigen when tested in an enzyme-linked immunosorbent assay. Each immunoprecipitated the corresponding in vitro translated products of human c-erbA alpha 1, alpha 2, or beta. Two of the antisera were specific for beta, one for alpha 2, and one detected a sequence common to alpha 1 and alpha 2. The fifth was directed toward the DNA-binding area of the proteins and interacted with each receptor. The four antibodies against alpha 1 and beta immunoprecipitated the native thyroid hormone receptor from rat liver and caused a partial shift in the elution profile of the native receptor labeled with [125I]T3 on Sephacryl S-300 column chromatography. The antibody against alpha 2 protein did not interact with native thyroid hormone receptor from rat liver. Using the indirect immunofluorescence technique with the five antibodies, we detected immunoreactivity primarily in the nucleus of cells in several tissues. In general, there was coordinate expression of both alpha and beta receptors in each organ examined, in agreement with previous data on tissue distribution of mRNAs for human thyroid hormone receptors. These studies prove the identity of v-erbA-related gene products with native thyroid hormone receptors and the expression of both alpha and beta receptors in nuclei of human and rat tissues.

Measurements of 129I in human and bovine thyroids in Europe--transfer of 129I into the food chain.

Bovine thyroid glands from different countries in Europe and human thyroid glands from Lower Saxony (Federal Republic of Germany) show isotopic 129I/127I ratios of 2.1 X 10(-9) to 8.2 X 10(-8) for cattle and 2.1 X 10(-9) to 8 X 10(-8) in humans. These values give information about the concentration of fallout 129I in Europe since most of these glands were collected in areas without nuclear facilities. Some of the human thyroids were collected after the Chernobyl accident between May 1986 and February 1988. Results obtained from human thyroids taken in some locations of Lower Saxony show no significant increase of the 129I during this time. Higher concentrations of 129I were only found in cattle grazing in the vicinity of a reprocessing plant in Mol, Belgium. Samples of soil, vegetation, milk, and water from this area contained higher than normal concentrations of 129I. The long-term transfer of radioiodine from the soil to the plant and the translocation within the soil were studied using a soil monolith with a 129I-contaminated surface. During the 4 y of the experiment, the transfer factor plant/soil decreased from 0.3 to 2.2 X 10(-3). Soil samples taken in 5-cm steps to a depth of 30 cm then at 40 and 50 cm depths showed that the transport of radioiodine to lower layers proceeds very slowly. The top 5-cm layer contained about 80% of the total radioactivity 52 mo after contamination. In an in-vivo study with a dairy cow, the transfer of radioiodine from feed to milk to cow meat and to pig thyroid gland was followed for 53 d using 129I-labeled pasture grass contaminated via roots. A part of the milk obtained from the cow was fed to a pig as a substitute for humans. The mean value of the transfer factor milk/feed was 2.4 X 10(-3) d kg-1. The values of the transfer factor cow meat/feed obtained for different muscle cuts and organs (excluding thyroid) ranged between 3.0 X 10(-4) (kidney) and 5.4 X 10(-2) d kg-1 f.w. The transfer factors pig thyroid/milk (as pig feed) and pig thyroid/cow feed exhibited values of 1.2 and 8.7 X 10(-3) d kg-1 f.w., respectively.

Direct evidence for the presence of methylmercury bound in the thyroid and other organs obtained from mice given methylmercury; differentiation of free and bound methylmercuries in biological materials determined by volatility of methylmercury.

Peroxidase in mouse thyroid was inhibited by mercuric chloride but not by methylmercury in in vivo and in vitro systems (Nishida, et al., J. Histochem. Cytochem., 37, 723 (1989)). To identify the reason for the difference, the present study was conducted to examine whether methylmercury is indeed bound within cells or tissues. Mice were given radioactive methylmercury by intubation for 18 d and the tissues were dissected out and vacuum-dried. With this procedure, free methylmercury was evaporated off and the bound mercury remained. The thyroid, liver, kidney and fats examined showed no loss of radioactivity under the vacuum, indicating that the mercury was bound to the thyroid, as well as the other tissues. Radioactive mercuric chloride was nonvolatile regardless of the presence or absence of the tissues. The preferential affinity of methylmercury for SH-containing materials was re-confirmed by this method.

The effects of different iodide availabilities on thyroid function during development in Japanese quail.

Japanese quail (Coturnix japonica) were used to study the effects of different egg iodide (I) availabilities on thyroid function during development. Low (less than 50 micrograms 1/kg feed in the maternal diet) and high (1200 micrograms 1/kg feed) I availability were compared to control levels (800 micrograms 1/kg feed), a standard supplementation for game bird feed. We measured thyroid gland content of I, triiodothyronine (T3) and thyroxine (T4), plasma concentrations of T3 and T4, hepatic 5' monodeiodinase (5'-D) activity, and the response of the thyroid gland to thyrotrophin (TSH) stimulation. Embryos, on day 14 of the 16.5-17 day incubation period, and 1-day chicks were used for most studies but thyroid gland hormone content and plasma hormone concentrations were determined for more stages. With high I, thyroidal I content was elevated but thyroidal T4 and T3 were not different from controls. Plasma T3 and T4, the thyroid gland response to TSH stimulation, and hepatic 5'-D activity did not differ between control and high I. Reduced body weight occurred with high I. In general, thyroid gland weight was not altered, but some high I birds exhibited thyroid hypertrophy and altered thyroid gland function. With low I availability, thyroid gland contents of I and T4 were reduced but thyroidal T3 content was maintained. The thyroid gland response to TSH stimulation, plasma thyroid hormone concentrations, and the developmental patterns of plasma thyroid hormones, hepatic 5'-D activity, body weight and thyroid weight were not different between control and low I groups. Developing Japanese quail exhibit excellent ability to adjust thyroid function over a wide range of I availabilities. Regulation appears to occur at the level of thyroid hormone synthesis in the thyroid gland, which allows most aspects of thyroid dynamics to remain unchanged in the maintenance of circulating thyroid hormone concentrations.

Radionuclide uptake and growth of barn swallows nesting by radioactive leaching ponds.

Populations of barn swallows (Hirundo rustica) nested seasonally near the Test Reactor Area (TRA) radioactive leaching ponds on the Idaho National Engineering Laboratory (INEL). These birds utilized leaching pond arthropods as a food source and contaminated mud for nest construction and thus accumulated radioactive materials. Over 20 fission and activation products were detected in immature and adult TRA birds. The radionuclide exhibiting the highest mean concentration in adult birds was 51Cr, with 16.1 Bq g-1 (435 pCi g-1). Mean concentrations of detectable radionuclides were used to calculate internal dose rates. Approximately 72% of the total dose rate of 219 microGy d-1 (22 mrad d-1) for adult birds was due to 24Na. Swallow thyroids contained a mean 131I concentration of 3330 Bq g-1. An average dose rate to the thyroid was calculated to be 4300 microGy d-1 or 450 mGy (45 rad) for the entire breeding season. Data from LiF-700 thermoluminescent dosimeters in swallow nests indicated that average dose rates were 840 microGy d-1 for eggs and 2200 Gy d-1 for nestlings, for a total of 54 mGy (5.4 rad) during the nesting period. The breeding biology and growth rate were investigated for TRA swallows and comparison group located 15 km and 100 km away. Total mortality rates for the comparison group vs. 1976 and 1977 TRA populations were not found to be significantly (p greater than 0.9) different. Nonlinear regression was used to fit individual growth curves and estimate parameters using a logistic model. First clutch TRA swallows were found to have a significantly (p less than 0.05) lower mean growth rate compared to either the first clutch comparison group or the second clutch of TRA birds. Mean asymptotic weights achieved by immature TRA birds were also found to be significantly (p less than 0.05) lower than those achieved by comparison group birds. Both growth rate and asymptotic weights for TRA birds were within the normal range reported in the literature. The cause for the statistical difference in growth rate between the comparison group and TRA first clutch populations could not be determined.

Distribution of Gal alpha 1----3Gal beta 1----4GlcNAc residues on secreted mammalian glycoproteins (thyroglobulin, fibrinogen, and immunoglobulin G) as measured by a sensitive solid-phase radioimmunoassay.

The study of the expression of Gal alpha 1----3Gal beta 1----4GlcNAc residues on mammalian glycoconjugates is of particular interest since as many as 1% of circulating IgG antibodies in man (the natural anti-Gal antibody) interact specifically with this carbohydrate residue. In recent studies, we have found that Gal alpha 1----3Gal beta 1----4GlcNAc residues are abundant on red cells and nucleated cells of nonprimate mammals, prosimians, and New World monkeys, but their expression is diminished in Old World monkeys, apes, and humans. In the present work, we have analyzed the expression of these residues on secreted mammalian glycoproteins. For this purpose, we have developed a radioimmunoassay (RIA) which enables the quantification of Gal alpha 1----3Gal beta 1----4GlcNAc residues on the secreted glycoproteins. Purified biotinylated anti-Gal was used as the antibody in the RIA, and bovine thyroglobulin enriched for Gal alpha 1----3Gal beta 1----4GlcNAc residues served as a solid-phase antigen. In this study, it is reported for the first time that the evolutionary pattern of Gal alpha 1----3Gal beta 1----4GlcNAc residue distribution in in vivo secreted glycoproteins is similar to that observed in membranes of cell lines and of red cells. Thyroglobulin, fibrinogen, or IgG molecules from nonprimate mammals and from New World monkeys express varying amounts of Gal alpha 1----3Gal beta 1----4GlcNAc residues ranging between 0.01 and 11 residues per molecule, whereas no such residues are present on any of these glycoproteins of human or Old World monkey origin.(ABSTRACT TRUNCATED AT 250 WORDS)

Thyroid iodine content and serum thyroglobulin level following external irradiation to the neck for Hodgkin's disease.

Fifty-four clinically euthyroid patients were evaluated 1 up to 17 yr after external irradiation to the neck for Hodgkin's disease. T4 level was decreased in 6%, while basal TSH level was increased in 44%, and TSH response to TRH was increased in 66% of the patients with normal basal TSH level. Thyroid iodine content (TIC), measured in 50 patients, was below 5 mg in 18. The 29 patients with normal basal TSH level had a mean TIC (6.8 +/- 2.7 mg) significantly lower (p less than 0.01) than the control population (14.6 +/- 5 mg). A significant positive correlation was found between log T4 and log TIC (r = 0.55, p less than 0.01). Thyroglobulin (Tg) level was increased in 53% of the patients with no palpable thyroid abnormality. It was not related to TSH level but was related to younger age at irradiation. T4 treatment decreased Tg level to the normal range in 5 of 8 patients. These facts suggest subclinical thyroid abnormalities and patients with elevated Tg levels should be considered at risk for developing a thyroid tumor.

Stimulation of adult chondrocyte metabolism by a thyroid-derived factor.

This paper reports the effects of adding partially purified bovine thyroid calcitonin, thyrocalcitonin, to adult bovine articular cartilage cells. Thyrocalcitonin stimulated chondrocyte proliferation fourfold under low serum (0.5%) culture conditions. In serum-free medium, thyrocalcitonin stimulated cell proliferation more than twofold. With high-density cultures in serum-free medium, chondrocyte glycosaminoglycan (GAG) synthesis was stimulated 60% by thyrocalcitonin. Cell-associated radioactivity was increased twofold. In contrast to thyrocalcitonin, addition of human and salmon calcitonin peptides as well as the thyroid hormones T3 and T4 had no effect on adult cartilage cell proliferation or GAG synthesis. The data reported here suggest the existence of a thyroid-derived factor, independent of calcitonin peptides or thyroid hormones, which stimulates adult articular chondrocyte metabolism.

Effects of elevated iodine in milk replacer on calf performance.

Calves were fed milk replacer containing .57, 10, 50, 100, or 200 ppm iodine (from ethylenediaminedihydroiodide) in DM, from 3 to 38 d of age, to estimate the minimum toxic concentration of iodine. Only the 200 ppm iodine intake reduced weight gains, DM intake, feed efficiency, and DM digestibility. At the 100 and 200 ppm iodine intakes, protein digestibility was reduced, and calves showed typical symptoms of iodine toxicity (nasal discharge, excessive tear and saliva formation, and coughing from tracheal congestion). Thyroid iodine increased with every elevation in iodine intake. Iodine in plasma, bile, and non-thyroid tissues started to increase at the 50 ppm intake and, except for muscle, tended to increase again at the 100 and 200 ppm intakes. Thus, the preruminant calf tolerated up to 50 ppm iodine in milk replacer DM for 5 wk postpartum. However, as iodine concentrations in plasma and nonthyroid tissues started to increase at 50 ppm iodine, an upper limit of 10 ppm would be more preferable.

Detection of calcitonin-encoding mRNA by radioactive and non-radioactive in situ hybridization: improved colorimetric detection and cellular localization of mRNA in thyroid sections.

The localization of mRNA encoding calcitonin was studied by in situ hybridization using 35S-labeled RNA probes and biotin-labeled DNA probes. Radiolabeled probes were detected by autoradiography and biotin-labeled probes by streptavidin-biotin-peroxidase. To intensify the colorimetric signal, the indirect avidin-biotin complex (ABC) method was performed. However, the results were often variable. To improve the sensitivity, the peroxidase reaction signal was enhanced with a gold-silver deposit intensification reaction. To shorten the incubation times and to enhance the colorimetric reaction, several reaction steps were performed in a microwave oven. The localization of calcitonin mRNA in thyroid tissue, as detected with in situ hybridization, was confirmed by immunohistochemical localization of the calcitonin polypeptide. The results of in situ hybridization using biotinylated probes were compared to in situ hybridization using radioactive probes. Our data show that the results of in situ hybridization applied on frozen and paraffin-embedded sections using biotinylated DNA probes, detected with an indirect streptavidin-biotin-peroxidase reaction and intensified by silver-gold enhancement, were comparable to those obtained with radioactive probes. The localization of calcitonin encoding mRNA was in agreement with the localization of the calcitonin polypeptide.

Immunoreactive atrial natriuretic peptide in the thyroid gland.

Human thyroid follicles and primary cell cultures derived from them demonstrated atrial natriuretic peptide (ANP)-like immunoreactivity when stained with a monoclonal antibody raised against rat alpha-ANP (ANP 1-28). In thyroid sections the staining was most intense in the tall cuboidal epithelium of small follicles. The intracellular distribution of immunoreactive (ir)-ANP in primary cultures of thyroid follicular cells consisted of discrete granules with a largely perinuclear distribution. The granule density increased with time in culture but was unaffected by exogenous ANP, suggesting an intrinsic synthesis of the immunoreactivity. Thyroid stimulating hormone (TSH; thyrotropin) failed to alter the distribution of ir-ANP after either short-term (6 h) or long-term (1-12 day) exposure. Epinephrine or norepinephrine treatment, however, caused a reduction in the ir-ANP granularity compared with controls in what might represent a stimulated release of the immunoreactivity. The present results suggest that the peptide ANP coexists with thyroid hormones in follicular cells and that the two endocrine activities might be under separate control mechanisms.

[Expression of ras oncogene product P21 in thyroid tumors: an immunohistochemical study].

The p 21 product of ras oncogene has been detected immunohistochemically in normal, inflammatory, benign and malignant human thyroid tissues. With the monoclonal antibody SCI-oncogene I and an avidin-biotin-peroxidase complex (ABC), the expression of ras p 21 was evaluated in paraffin-embedded sections. The results showed that papillary and follicular adenocarcinomas of the thyroid had moderate to intense staining for ras p 21 in most cases. Cytoplasmic and apical surface staining were the most common patterns of immunoreactivity. Adenomas showed slight positive or negative staining in cytoplasm. Normal thyroid tissues and thyroiditis were uniformly negative. Grave's disease revealed slight to moderate staining in some cases. These findings suggest that ras oncogene is involved in carcinogenesis of thyroid carcinomas. Enhanced expression of ras p 21 may be useful in differentiation of thyroid adenocarcinomas from adenomas and may be a valuable parameter in evaluating biological behavior of tumors.

Thyroidal 125I monitoring system using an NaI (Tl) survey meter.

This paper describes the counting efficiency and detection limit of a thyroidal 125I monitoring system. Two systems were used: (1) M1 was composed simply of one survey meter for 125I (SM) having an NaI (Tl) crystal of 5.08-cm diameter by 5-mm thick, and (2) M2 was composed of the SM having an output terminal for spectroscopy and a multichannel pulse height analyzer. The counting efficiency was determined by using four simulated thyroids of 17, 20.5, 31, and 40 mL containing 125I solution. The simulated thyroids were embedded in an anthropomorphic neck phantom. The counting efficiency between 0 degrees and 45 degrees to the normal of the thyroid (front of the neck) changed by +/-2%. The efficiency of M1 ranged from 1.8 to 7.9% as the distance between the probe and the neck increased from 0 to 5 cm. Similarly, the efficiency of M2 ranged from 2.2 to 8.3%. The detection limit ranged from 7 to 34 Bq for M1 and from 1 to 5.1 Bq for M2. The M2 system was applied to monitoring a worker performing iodination with 74 MBq Na 125I. Both monitoring systems provided the necessary sensitivity to detect thyroidal 125I within the uncertainty of +/-10%.

Immunocytochemical localization of bovine thyrotropin and thyroid auto-antibodies in porcine thyrocytes.

Interactions of receptor-bound bovine thyrotropin (bTSH) and immunoglobulins G from sera of patients with Graves' (G-IgG) or Hashimoto's (H-IgG) disease with porcine thyrocytes were studied by immunocytochemistry. Porcine thyroid fragments were fixed and prepared for immunoreaction or enzymatically dissociated with collagenase and dispase II. The dispersed cells were cultured in primary monolayer in a hormone-free medium or in a medium with bTSH (150 micrograms/ml) for 7 days. After immunostaining the thyrocytes in fragments and monolayers were stained with periodic acid Schiff (PAS) or with PAS and haemalum. Cultivation of the isolated thyrocytes in bTSH-enriched medium leads to a monolayer with globular aggregates, i.e., reconstructed three-dimensional follicles. Follicular cells in these monolayers and in fragments give a weak to moderate immunoreaction to anti-bTSH and a strong reaction to G-IgG and H-IgG (vs. control IgG). Precipitate is found particularly in the perinuclear area and to a lesser degree throughout the cytoplasm. Cells cultured in the absence of bTSH show minimal immunoreaction to anti-bTSH, but moderate reaction to G-IgG and H-IgG. Preincubation with bTSH leads to a strong reduction of immunoreaction to G-IgG but does not affect reaction to H-IgG. Morphological results indicate that G-IgG and H-IgG interact with the same cellular sites as bTSH. Hashimoto's disease antibodies bind to a determinant on the TSH receptor separate from the one on which TSH and Graves' IgG bind.

Evidence for false aneuploid peaks in flow cytometric analysis of paraffin-embedded tissue.

It has recently been shown that bimodal histograms with false aneuploid peaks may be obtained by DNA flow cytometry from histologically normal tissue allowed to autolyze. To investigate if such peaks can be generated from surgically excised archival tissue, 198 paraffin blocks from 179 patients containing histologically normal spleen (n = 65), liver (n = 26), thyroid (n = 32), pancreas (n = 19), salivary gland (n = 49), or lymph node tissue (n = 7), obtained from the archives of two university pathology departments, were analyzed for nuclear DNA content. The great majority (n = 160, 83.8%) of the 191 interpretable histograms had a single symmetrical G1 peak; and 8 histograms, all produced from liver tissue had a tetraploid pattern. A slight or a prominent repeatable deviation in the G1 peak outline was present in 14 (7.3%) cases. A peak resembling an aneuploid G1 peak with a DNA index (DI) ranging from 1.14 to 1.38 was repeatedly produced from 9 (4.7%) blocks containing histologically normal or inflamed splenic (n = 3), pancreatic (n = 3), liver (n = 1), thyroid (n = 1), or lymph node (n = 1) tissue. The three abnormal peaks produced from pancreatic tissue were rounded in shape and resembled closely the ones that can be obtained from autolytic pancreatic tissue, and the six remaining extra peaks were all fused with the "diploid" peak. In conclusion, false peaks, probably caused by degradation of the nuclear contents during formalin fixation or before it, may rarely be obtained from surgical paraffin-embedded samples.

Immunohistochemical localization of chromogranin A in normal tissues from laboratory animals.

To analyze the distribution of Chromogranin A in endocrine cells of various species of laboratory animals (dog, gerbil, guinea pig, hamster, monkey, mouse, and fetal, neonatal, and adult rats), normal tissues were stained immunohistochemically with polyclonal anti-bovine Chromogranin A antiserum (SP-1). Selected tissues (pituitary, adrenal, thyroid, parathyroid, pancreas, brain, peripheral nerve, stomach, small and large intestine, bone marrow, spleen, thymus, lymph node, and liver) from these species and from the rabbit were stained with two monoclonal anti-human Chromogranin A antibodies (LK2H10 and PHE5) to compare the immunoreactivities of the monoclonal antibodies and polyclonal antiserum. Staining with the polyclonal antiserum (SP-1) resulted in a broader spectrum of immunoreactivity but had more nonspecific background staining than either monoclonal antibody. Immunoreactivity and staining intensity with SP-1 varied between species, but most endocrine tissues (pituitary cells in the anterior and intermediate lobes, thyroid "C" cells, adrenal medulla, parathyroid, pancreatic islets, and enterochromaffin cells) from most species stained positively. In some species, pancreatic alpha cells stained more intensely, and two populations of adrenal medullary cells with different staining intensities were observed. Sciatic nerve (axonal area) was immunoreactive with monoclonal antibodies and/or the polyclonal antiserum in several species. The spectrum of immunoreactive tissues from fetal and neonatal rats increased with age. There was good cross-reactivity between species with SP-1, but not with either LK2H10 or PHE5. These results indicate that many endocrine cells with secretory granules in laboratory animals express Chromogranin A and that a polyclonal antiserum, such as SP-1, is more sensitive in detecting this protein in various species than monoclonal antibodies such as LK2H10 or PHE5.