Herring Body Research Articles

A study of the gonadotropin releasing hormone neuronal network in the median eminence of the rhesus monkey ( Macaca mulatta) using a post-embedding immunolabelling procedure.

The purpose of this study was to describe the ultrastructural features of gonadotropin releasing hormone (GnRH) axonal processes in the median eminence of the monkey, using a post-embedding immunogold labelling procedure. Evidence was also sought to evaluate the view that release of this peptide may be governed by direct inputs to GnRH axons in the median eminence. Plastic embedding was used to preserve ultrastructure, and a polyclonal rabbit anti-GnRH was used as primary antibody. Immunogold labelling with 15-nm particles was almost exclusively found overlying dense core vesicles (dcvs) and preabsorption of the primary antibody with synthetic GnRH eliminated this labelling. Morphometric analysis was performed on tissue from two monkeys. Four types of profiles containing GnRH immunoactive dcvs were observed. Type I profiles were morphologically unremarkable with a cross sectional area of approximately 0.6 microm2 and probably represent intervaricose axon segments. Type II profiles, which were nominally larger than Type I structures, were characterized by a high density of round microvesicles, which were frequently concentrated along the neuronal membrane to form 'synaptoid' contacts with adjacent glia. Two additional and large GnRH profiles (>5 microm2) were observed. One (Type III) contained a high density of dcvs and mitochondria, and was considered analogous to an axonal swelling or Herring body in the magnocellular hypothalamo-neurohypophysial system. The Type IV structure, which was considered not to be a Herring body because of the relative low density of mitochondria was innervated by a classical symmetrical synapse. The functional significance of these observations is discussed.

A Standard Weight Equation to Assess the Condition of North American Lake Herring (Coregonus artedi)

We developed a 75th-percentile standard weight (Ws) equation to aid in the analysis of lake herring (Coregonus artedi) body condition over temporal periods and across populations. Weight-length data were obtained for 23,115 lake herring from 61 North American populations. The proposed equation is log10 Ws = −5.517 + 3.224 log10 TL, where Ws is the standard weight in grams and TL is the maximum total length in millimeters. The equation is valid for lake herring ≥ 100 mm and allows calculation of the relative weight (Wr) index. Significantly lower (P<0.001) Wr values were present for Lake Superior lake herring populations than for the “inland” populations, suggesting that Lake Superior herring weigh less at a given length. Based on the world record lake herring length (55.9 cm), we propose minimum standardized length categories of 13,20,28,35, and 43 cm for stock, quality, preferred, memorable, and trophy lengths, respectively. The length categories facilitate analysis across length groups and the calculation of stock density indices.

Cytoskeletal organization in the neurohypophysial axons of rats

Cytoskeletal organization in axons of the rat neurohypophysis was examined by quick-freeze deep-etch electron micrscopy and conventional thin-section electron microscopy. In the neurohypophysial axons, neurotubules and neurofilaments were arranged almost in parallel with each other, and interlinked by cross-bridges. Because the localization of MAP1A on the axonal cytoskeleton was shown by immunoelectron microscopy, MAP1A is a component of the cross-bridges between neurotubules. The neurotubules and neurofilaments occupied their respective domains in the axon. The neurotuble:neurofilament ratio was variable axon by axon. In some axons, neurotubules overwhelmed neurofilaments in number. In other axons, neurofilaments were predominant, and neurotubules were few. The neurosecretory granules were located in association with either the neurotubule or neurofilament domain. Fine fibrils 5–10 nm in diameter were associated with the inner surface of the axonal plasmalemma. In the Herring body, a few neurotubules occurred in the marginal region while neurofilaments were rarely seen, indicating that most of the neurosecretory granules have no relationship with the neurotubules in the body. These results suggest that the cytoskeleton in neurohypophysial axons may be involved in regulation of axonal transport and storage of neurosecretory granules.

A study of the composition of fish liver and body oil triglycerides.

Silver-ion high-performance liquid chromatography (Ag(+)-HPLC) was used to study the range and variations in molecular species of triglycerides from industrial, retail and laboratory extracted fish oils. These were contrasted with a typical plant oil. Selected fish oils were fractionated and the fatty acid distribution of the fractions determined by gas-liquid chromatography. Fish oils gave a characteristic Ag(+)-HPLC profile, typified by sharp, intense peaks at the start of the chromatogram and broad, multiple nongaussian peaks for the late eluting components. Triglycerides ranging from those that were wholly saturated to those containing 16 double bonds were isolated. Cod (Gadus spp.), saithe (Pollachius virens) and monkfish (Squatina squatina) liver oils gave similar triglyceride profiles. Mackerel (Scomber scombrus), capelin (Mallotus villosus) and herring (Clupea harengus) body oils gave characteristic triglyceride profiles which were associated with high concentrations of 20:1 and 22:1 fatty acids. Only small amounts of these particular triglycerides were observed for menhaden (Brevoortia spp.), South African anchovy (Engraulis capensis) and Indian sardine (Sardinella longiceps) oils, all of which contained minor amounts of these acids. The latter oils contained highly unsaturated triglycerides, whereas only traces of these were noted for the former. Chromatography with Ag(+)-HPLC can be used for the rapid screening of fish oils and for selecting those oils rich in polyunsaturated acids that may be suitable for enrichment. Cottonseed oil gave well-defined and discrete peaks. Similar peaks were observed in the chromatogram of Omega-combination, a mixture of primrose and fish oils. Thus, fish, plant and a mixture of these oils can be readily distinguished.

Ultrastructural studies on the secretory cycle of the neurosecretory cells and the formation of Herring bodies in the paraventricular nucleus of the rat.

The ultrastructure of the neurosecretory cells in the paraventricular nucleus of the normal male rat was studied by electron microscopy during various functional states. Four morphologically distinct types of neurosecretory cells were observed. It appears that they do not represent different classes of cells but different phases of secretory activity of a single cell type. The perikarya of the neurosecretory cells show a definite cycle of formation and transportation of secretory granules. We have designated the phases of this cycle as: (1) phase of synthesis, (2) phase of granule production, (3) phase of granule storage and (4) phase of granule transport. The neurosecretory granules appear to be moved in bulk into the axons, forming a large axonal swelling filled with granules as a result of one cycle in the neurosecretory process. Thus it may be postulated that a secretory cycle in the perikaryon of the neurosecretory cell seems to result in the formation of a Herring body in its axon, and that its content is then conveyed to the posterior pituitary.

Herring bodies; an electron microscopic study of local degeneration and regeneration of neurosecretory axons.

The Herring bodies in the posterior lobe of the bovine hypophysis are very large (2–600 μ) and can be classified into three types. The type I Herring body contains an accumulation of neurosecretory granules. These Herring bodies are very scarce and should not be confused with the numerous, but small, axonal swellings which also contain neurosecretory granules.

Electron Microscopic Observation on the Neurosecretory Granules in the Pituitary Posterior Lobe of Dog

Electron microscopic observation was made on the pituitary posterior lobe of dog.1. Round, oval or cylindrical, light-toned areas measuring 1-5μ in width with capsule of double membrane were seen in the posterior lobe of the hypophysis. A large number of small granules may be seen within these areas. Some of the capsules may be found in close contact with the pituicytes. The relation of these areas to the nerve fiber is still to be investigated, but some of them can be presumed to be in the nerve fiber.2. Considering the size and the character of the granules, it is assumed that the granule is identical to the gomoriphil neurosecretory substance.3. Occasionally, areas surrounded by capsule and filled with granules may be seen. These are assumed to be identical with the HERRING's body.4. The granules are spherical with diameter of 100-300mμ. Those observed within the HERRING's body have diameter of 80-150mμ. Most of the granules have light halo burring in thickness of 100Å between the boundary membrane and the center portion of high electron density. Some of the granules lack the halo burring, with the central portion either high or low in electron density.