Pacific Hagfish Research Articles

Role of the liver in regulation of carbohydrate metabolism in hagfish, Eptatretus stouti

1. 1. Hepatectomized hagfish survived 5–30 days without administration of glucose. 2. 2. In contrast to other vertebrates, hepatectomized hagfish experienced only a transient hyperglycemia, as did the sham-operated animals. 3. 3. Plasma amino nitrogen levels were unchanged after hepatectomy. 4. 4. These data, together with activities of glucose-6-phosphatase in various organs, suggest that the liver of this primitive animal does not serve the same regulatory function in carbohydrate metabolism as in higher vertebrates.

Sensitivity of Pacific hagfish, Eptatretus stouti, to mammalian insulin

Long-lasting hypoglycemia and depression of plasma amino nitrogen levels were produced in Pacific hagfish, Eptatretus stouti, by injection of as little as 0.1 to 0.5 IU/kg of bovine insulin. This, in contrast with earlier information from Myxine glutinosa, indicates that the metabolic sensitivity of Eptatretus to mammalian insulin is at least as great as that in most higher vertebrates. However, the long-lasting character of the hypoglycemia and depressed plasma amino nitrogen argue for poorly developed antihypoglycemic metabolic mechanisms in this cyclostome.

Ultrastructure of the Testicular Interstitial Tissue of the Hagfish Eptatretus stouti

AbstractUltrastructure of the somatic components of the testis of the Pacific hagfish was studied. Interstitial cells, equivalent to Leydig cells of higher vertebrates, containing smooth‐surfaced endoplasmic reticulum and mitochondria with tubular cristae were found in the interstitial tissue, as well as leucocytes, fibroblasts and other cells of unknown role. Two kinds of somatic cells were observed in the testicular follicles: Sertoli cells and “stellate cells”. The significance of interstitial cells was discussed in relation to possible involvement in steroidogenesis.

Ultrastructure of the Ovary of the Hagfish Eptatretus stouti

AbstractUltrastructure of the ovary of the Pacific hagfish was studied. Attention was paid to the mesovarium, small oocytes, oocytes of intermediate size, large oocytes, postovulatory follicles shortly after ovulation, postovulatory follicles considerably after ovulation, and preovulatory atretic follicles. The progressive changes of thecal and granulosa layers in the course of egg development and degeneration are described. No cells showing the ultrastructural characteristics associated with steroidogenesis were found.

In vitro thyrotropic effect of the pituitary of the pacific hagfish, Eptatretus stouti

Hagfish ( Eptatretus stouti) thyroid tissue was maintained in organ culture with hagfish pituitary or bovine thyroid-stimulating hormone (b-TSH). Possible thyrotropic effects of pituitary co-culture or b-TSH were assessed by radioimmunoassay of the thyroxine (T 4) concentration in culture medium. Thyroid tissue co-cultured with hagfish pituitary released a greater amount (20–100%) of T 4 into the medium than thyroid tissue cultured alone or with connective tissue (control). Addition of bovine thyrotropic hormone at two different doses (25 ng/ml and 25 μg/ml) resulted in a slight but statistically nonsignificant increase in T 4 levels. Stimulation of T 4 release during pituitary co-culture indicates the existence of a thyrotropic factor in the hagfish adenohypophysis.

The Olfactory System in the Pacific HagfishesEptatretus stoutii, Eptatretus deani, andMyxine circifrons

In front of the olfactory organ in the northeastern Pacific hagfishes Eptatretus stoutii, E. deani, and Myxine circifrons there is a valve that may function to direct water in between the olfactory laminae. In Myxine circifrons the well developed valve is supposed to act alone, whereas the smaller valve in the two species of Eptatretus studied is supposed to act together with the horizontal extensions of the median olfactory lamina. No significant differences were found between the investigated species by ultrastructural examination. In the olfactory epithelium the supporting cells are provided with microvilli and generally contain a great amount of light secretory granules. Both ciliated olfactory receptor cells and microvillous olfactory receptor cells are present. The cilia show a 9 + 0 arrangement of the microtubules with a tendency for a dislocation of one pair of the microtubules toward the center of the cilium. These remarkable features of the olfactory receptor cells, not yet seen in other vertebrates, appear to be a character common to the myxinoid cyclostomes.

Serum thyroxine concentrations in the Pacific hagfish and lamprey and in the leopard frog

Concentrations of thyroxine in samples of fresh serum, measured by use of a competitive protein binding procedure, averaged 3.4 μg/100 ml in Pacific hagfish ( Eptatretus stouii), 0.5 μg/100 ml in adult Pacific lampreys ( Entosphenus tridentatus), and 1.7 μg/100 ml in Mexican leopard frogs ( Rana pipiens complex).

Follicles in the Endocrine Pancreas of Some Myxinoid Species

A light microscopic study of the endocrine pancreas in some myxinoids has revealed a striking difference in the occurrence of follicles. Islet tissue follicles are regularly occurring and also abundant in Myxine glutinosa, but are sparse or absent in Eptatretus burgeri and Eptatretus stouti. Whether this is caused by a decreased need for insulin in Myxine glutinosa is discussed but remains an open question.

Hemagglutinins in the mucus of pacific hagfish, Eptatretus stoutii

1. 1. A disc electrophoretic and immunologic comparison was made of Pacific hagfish ( Eptatretus stoutii) serum and a concentrated, water-soluble fraction of mucus. 2. 2. Usually 12–15 protein components were obtained by disc electrophoresis of mucus and the profile was similar in many regions to that of serum. 3. 3. Usually at least two and sometimes four proteins of mucus could be shown to be immunologically related by double diffusion. 4. 4. Natural hemagglutinins which were found in mucus by direct hemagglutination were also shown to have heat-sensitivity similar to hemagglutinins in serum.

Fine Structure of Spermiogenesis in Eastern Pacific Species of Hagfish (Myxinidae)

Abstract Spermiogenesis in Eptatretus stoutii, E. deani and E. sp. display great similarities. Minor differences appear in the acrosomal structure. The spermatozoan has a long middle piece in which the axonema is surrounded by a sheath, consisting of a very few mitochondria, a feature usually associated with internal fertilization.

Thyroxine and protein-bound iodine concentrations in plasma of the pacific hagfish, Eptatretus stouti (Cyclostomata)

1. 1. Plasma levels of thyroxine (T 4) were determined by competitive protein-binding analysis and compared with plasma concentrations of protein-bound iodine (PBI). 2. 2. Measurements were made on samples from normal, hypophysial-Lesioned and sham-operated fish. 3. 3. In normal animals, which had been held in the laboratory for 3 weeks, the measured T 4 values ranged from 2 to 3 μg/100 ml of plasma and PBI levels varied from 5 to 8 μg/100 ml. 4. 4. T 4 concentrations were significantly lower in both the hypophysial-Lesioned and sham-operated fish which had been maintained in the laboratory for 18 weeks. 5. 5. PBI levels tended to be lower in the experimental fish than in normal animals, but the differences were not significant. 6. 6. In both normal and experimental hagfish, thyroxine iodine comprised less than one-third of the plasma content of organic iodine.

A technique for hypophysectomy of the Pacific hagfish: First observations

Complete hypophysectomy of seven Pacific hagfish, Eptatretus stouti, produced clearly degenerative changes in testes, but less clear changes in ovaries after 3 mo. No changes were observed in thyroid structure, pigmentation or in behavior.

Thyroglobulins of cyclostomes and an elasmobranch

As part of a study of the biosynthesis and physicochemical properties of primitive vertebrate thyroglobulins, the thyroid-containing tissues of Pacific hagfish ( Eptatretus stouti) and of Pacific lamprey ( Entosphenus tridentatus), and thyroid glands of Pacific dogfish ( Squalus suckleyi) were used. In the hagfish thyroid tissues labeled with radioiodine, only 3–8S iodoprotein having an approximate molecular weight of 155,000 was detectable. A low proportion of thyroid iodine was in the form of labeled thyroxine (2.5%) 4 days after labeling. In lamprey thyroid tissue radioactivity peaks corresponding to 3–8S and 19S proteins were found in ultracentrifugation patterns. However, the main thyroid iodoprotein component purified by ammonium sulfate fractional precipitation was 12S. The proportion of labeled thyroxine to total radioiodine in lamprey iodoproteins was 2.9%. Total iodine content of lamprey thyroprotein was 0.0022%. In dogfish thyroid glands only 19S thyroglobulin as obtained after purification by the ammonium sulfate procedure. Total iodine content was similar to that of mammalian thyroglobulins, 0.50%. The proportion of total iodine in the form of unlabeled thyroxine in an analysis of unlabeled dogfish thyroglobulin was at a high level of 50.9%. The amino acid compositions of lamprey iodoproteins and dogfish thyroglobulin differed in some respects from higher vertebrate thyroglobulins. There was also some difference in the carbohydrate compositions of lamprey iodoproteins and dogfish thyroglobulin, compared to higher vertebrate thyroglobulins. Moreover, the total carbohydrate content of lamprey iodoproteins and of dogfish thyroglobulin was lower than in higher vertebrate thyroglobulins. On the basis of these results the general properties of thyroglobulins could be considered with respect to the question of the evolution of thyroid function.

In Search of the Hagfish Thymus

The Pacific hagfish, Eptatretus stoutii , is capable of a variety of immunologic responses including allograft rejection and serum antibody production to soluble and cellular antigens. Interest has revived in the morphology of hagfish lymphoid tissues. The search for a thymus in young specimens has resulted in the discovery of a phagocytic and antigen-receptive cell population associated with the pharyngeal velar muscles. We suggest that a protothymus or precursor of the thymus of higher vertebrates may be contained within this velar muscle complex.

Preliminary structural characterization of Pacific hagfish immunoglobulin.

The immune capacities of primitive fishes of the class Agnatha, the lamprey and the hagfish, have been under study for nearly a decade. Early results from Good and his collaborators suggested that lampreys, but not hagfish, possessed an adaptive immune response (1, 2). However, subsequent work of Linthicum and Hildemann (3) and Hildemann and Thoenes (4, 5) showed that hagfish (Eptatretus stoutii) could also respond specifically to certain immunogens and could reject allografts under appropriate conditions.

Renal sodium reabsorption in the hagfish, Eptatretus stouti

1. 1. In 1964 Münz & McFarland stated that “of great importance in the question of vertebrate origins is the fact that hagfish apparently lack any renal mechanism for the reabsorption of sodium from the glomerular filtrate” and that this “is fundamental physiological evidence that myxinoids have always been marine”. 2. 2. The present findings show that the same species of hagfish, Eptatretus stouti, possesses the typical vertebrate ability to recover sodium ions from the glomerular filtrate. 3. 3. The evolutionary conclusions of the Munz and McFarland study are discussed.

The pharmacological characterization of arginine vasotocin in the pituitary of the pacific hagfish ( Polistotrema stoutii)

Studies of extracts of the neurohypophysis of the Pacific hagfish, Polistotrema stoutii, have shown the presence of low oxytocic activities (0.23 ± 0.04 mU/mg lyophilized powder). Only 25% of this activity was labile to 0.01 M sodium thioglycollate. Control tissue from the hindbrain showed approximately one-half the oxytocic activity of the neurohypophysial tissue; the hindbrain activity increased after thioglycollate treatment. Since studies on crude extracts were not reliable, because of the many complicating factors, purification was carried out. Preliminary treatment with TCA was almost without effect. Column chromatography on carboxymethyl cellulose gave no evidence for a neutral principle. However, a basic oxytocic agent was eluted at a position typical of AVT. A 40.7-fold purification was achieved. The active agent was compared directly with synthetic AVT on multiple bioassays; there was a close parallel between the two peinciples. It was concluded that partial purification of neurohypophysial extracts of the hagfish, Polistotrema stoutii, gave clear evidence for the presence of arginine vasotocin, but no reliable indication of any other principle.

Properties of an iodoprotein from thyroid tissue of the Pacific hagfish, Eptatretus stoutii

In hagfish, thyroid tissue incorporation of radioiodine into proteins associated with cellular particulate matter reached a level of more than 50% of the total labeled iodoproteins. Only a single 3-8S iodoprotein was found by sucrose density gradient centrifugation of the soluble protein obtained from thyroid tissue by ultracentrifugation. No 19S thyroglobulin was found. Labeled thyroxine amounted to 2.5% of the total 131I in proteins.

The response of hagfish thyroid tissue to thyroid inhibitors and to mammalian thyroid-stimulating hormone

The response of the thyroid-containing tissue of the Pacific hagfish Eptatretus stoutii to antithyroid compounds and to mammalian thyroid-stimulating hormone (TSH) was studied. The accumulation of injected 131I was strongly inhibited by pretreatment of the animals with goitrogenic drugs. Both the uptake of 131I by the thyroid-containing tissue and the response to pretreatment with 2 USP units of bovine TSH was greater in animals studied several months after capture than in newly captured hagfish. After several months in captivity, the uptake of 131I in TSH-treated hagfish was 185% of the control value 2 and 4 days after TSH administration. A higher percentage of labeled diiodotyrosine and thyroxine and a lower percentage of monoiodotyrosine was observed in the thyroid tissue of TSH-treated hagfish.

Effects of cold exposure on cardiac metabolism of the turtle Pseudemys (Chrysemys) picta.

ARTICLESEffects of cold exposure on cardiac metabolism of the turtle Pseudemys (Chrysemys) pictaRJ Beall, and CA PriviteraRJ Beall, and CA PriviteraPublished Online:01 Feb 1973https://doi.org/10.1152/ajplegacy.1973.224.2.435MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByThe role of DNA methylation during anoxia tolerance in a freshwater turtle (Trachemys scripta elegans)3 February 2016 | Journal of Comparative Physiology B, Vol. 186, No. 3Ascorbic acid regulation in stress responses during acute cold exposure and following recovery in juvenile Chinese soft-shelled turtle (Pelodiscus sinensis)Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Vol. 184The effect of temperature on mitochondrial respiration in permeabilized cardiac fibres from the freshwater turtle, Trachemys scriptaJournal of Thermal Biology, Vol. 37, No. 3Anoxic survival of the Pacific hagfish (Eptatretus stoutii)18 November 2010 | Journal of Comparative Physiology B, Vol. 181, No. 3Acid-Base status and ion balance during simulated hibernation in freshwater turtles from the northern portions of their rangesJournal of Experimental Zoology, Vol. 273, No. 6Evolutionary trends of LDH isozymes in fishesComparative Biochemistry and Physiology Part B: Comparative Biochemistry, Vol. 105, No. 1ECOLOGY AND PHYSIOLOGY OF HIBERNATION AND OVERWINTERING AMONG FRESHWATER FISHES, TURTLES, AND SNAKESBiological Reviews, Vol. 64, No. 4High energy organophosphate levels in the myocardia of cold acclimated and cold-hypoxic freshwater turtles, Chrysemys pictaComparative Biochemistry and Physiology Part A: Physiology, Vol. 92, No. 2Immunochemical evidence that the single lactate dehydrogenase of lampreys is more similar to LDHB4 than to LDHA4 of hagfishJournal of Experimental Zoology, Vol. 241, No. 1Loggerhead turtle lactate dehydrogenases. How general is the apparent adaptation to prolonged anaerobiosis displayed by the lactate dehydrogenase isoenzymes from turtles of the genus Pseudemys?Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, Vol. 76, No. 1Anaerobic metabolism in freely diving painted turtles (Chrysemys picta)Journal of Experimental Zoology, Vol. 216, No. 3Purification and properties of turtle heart creatine kinase: role for the enzyme in glycolytic controlInternational Journal of Biochemistry, Vol. 6, No. 1 More from this issue > Volume 224Issue 2February 1973Pages 435-441 Copyright & PermissionsCopyright © 1973 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1973.224.2.435PubMed4686499History Published online 1 February 1973 Published in print 1 February 1973 Metrics