An argyrophil fibrillar system and amitotic nuclear division in pars intermedia cells of the rainbow trout (Salmo irideus)

1970 ◽  
Vol 108 (1) ◽  
pp. 59-80 ◽  
Author(s):  
J. Boddingius
Keyword(s):  
Rainbow Trout ◽  
Nuclear Division ◽  
Pars Intermedia ◽  
Amitotic Nuclear Division

The division process of Cryptobia salmositica in experimentally infected rainbow trout (Salmo gairdneri)

1978 ◽  
Vol 56 (7) ◽  
pp. 1514-1518 ◽  
Author(s):  
Patrick T. K. Woo
Keyword(s):  
Rainbow Trout ◽  
Nuclear Division ◽  
Coho Salmon ◽  
The Body ◽  
Binary Fission ◽  
Salmo Gairdneri ◽  
Division Process

Cryptobia salmositica was isolated from its vector, Piscicola salmositica, which was collected from spawning salmon. The organisms were first injected into coho salmon and then maintained in rainbow trout. The process of multiplication is described from Giemsa's stained smears. The first stage of division is the production of two new flagella (one long and one short). This is followed by nuclear division which is not completed until kinetoplast division is completed. Body division commences from the posterior end soon after the long flagellum attaches to the body. Following this, the nucleus, the kinetoplast, and the blepharoplast migrate into the newly divided part of the organism. Final body division is completed after the migration of these organelles. Multiplication of C. salmositica is by unequal longitudinal binary fission.

DIFFERENCES IN CONCENTRATIONS OF PLASMA CORTISOL IN THE TROUT AND THE EEL FOLLOWING ADAPTATION TO BLACK OR WHITE BACKGROUNDS

1981 ◽  
Vol 89 (1) ◽  
pp. 135-140 ◽  
Author(s):  
BRIDGET I. BAKER ◽  
THERESA A. RANCE
Keyword(s):  
Rainbow Trout ◽  
Plasma Cortisol ◽  
Binding Capacity ◽  
Anguilla Anguilla ◽  
Short Photoperiod ◽  
Salmo Gairdneri ◽  
Pars Intermedia ◽  
Total Cortisol ◽  
The Difference ◽  
Long Photoperiod

When rainbow trout (Salmo gairdneri) and eels (Anguilla anguilla) were kept in black tanks for 3—4 weeks, their plasma cortisol titres were about fourfold higher than in fish kept in white tanks. In trout, the difference was apparent only under a long photoperiod of 16 h light: 8 h darkness, but in eels the difference was clear under both a long or short photoperiod (9·5 h light: 14·5 h darkness). It is suggested that the increase in plasma cortisol seen in black-adapted fish is dependent on either ACTH or MSH secreted by the pars intermedia melanotrophs. No difference was seen either in the total cortisol-binding capacity of the plasma nor in interrenal histology in trout from black or white backgrounds.

scholarly journals Cloning of somatolactin alpha and beta cDNAs in zebrafish and phylogenetic analysis of two distinct somatolactin subtypes in fish

2004 ◽  
Vol 182 (3) ◽  
pp. 509-518 ◽  
Author(s):  
Y Zhu ◽  
JW Stiller ◽  
MP Shaner ◽  
A Baldini ◽  
JL Scemama ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Sequence Similarity ◽  
Anterior Part ◽  
Phylogenetic Analyses ◽  
Pars Intermedia ◽  
Pituitary Hormone ◽  
High Sequence Identity ◽  
Trace Back ◽  
Typical Range ◽  
Teleost Genome

Somatolactin (SL) is a pituitary hormone belonging to the growth hormone/prolactin superfamily, with recognizable homologues in all fish taxa examined to date. Although sequences from most fish share reasonably high sequence identity, several more highly divergent SLs have been reported. Goldfish SL and a second SL protein found in rainbow trout (rtSLP) are remarkably different from each other and also dissimilar to other SLs. It has been unclear whether rtSLP is a recent paralogue restricted to rainbow trout, or reflects a more ancient duplication of the SL gene, and whether it is related to the goldfish sequence. Here we report the cloning of two different zebrafish SL cDNAs, which share only 57.5% nucleotide and 47.7% deduced amino acid identities. One copy, designated zebrafish SLalpha (zfSLalpha), displays a typical range of sequence similarity to most other SLs. The other copy, zebrafish SLbeta (zfSLbeta), shows low identity to most other SLs; surprisingly, it is most similar to the divergent SL sequence from goldfish. The mRNAs of zfSLalpha and zfSLbeta were expressed specifically in two distinct regions of the pars intermedia in zebrafish. Cells expressing zfSLalpha are located at the posterior pars intermedia, bordering the neurohypophysis, whereas zfSLbeta is expressed in the anterior part of the pars intermedia, bordering the pars distalis. Phylogenetic analyses indicate that zfSLbeta, goldfish SL and rtSLP all belong to the SL hormone family; however, along with the genes from eel and catfish, these divergent sequences form a group that is clearly distinct from all other SLs. These results suggest the presence of two distinct SL families, SLalpha and SLbeta, which may trace back to a teleost genome duplication prior to divergence of the cyprinids and salmonids.

ACTH Production by the pars intermedia of the rainbow trout pituitary

1975 ◽  
Vol 27 (2) ◽  
pp. 193-202 ◽  
Author(s):  
Alexander P. Scott ◽  
Bridget I. Baker
Keyword(s):  
Rainbow Trout ◽  
Pars Intermedia

ROLE OF PROLACTIN AND SOMATOLACTIN IN CALCIUM REGULATION IN FISH

1993 ◽  
Vol 184 (1) ◽  
pp. 31-45 ◽  
Author(s):  
T. Kaneko ◽  
T. Hirano
Keyword(s):  
Rainbow Trout ◽  
Calcium Regulation ◽  
Prolactin Secretion ◽  
Pars Intermedia ◽  
Pituitary Hormone ◽  
Endocrine Control ◽  
Terrestrial Vertebrates ◽  
Fish Exposure ◽  
High Calcium ◽  
Plasma Calcium Concentration

The endocrine control of calcium metabolism in fish is performed by hyper- and hypocalcaemic hormones as in terrestrial vertebrates. However, the hormones involved in calcium regulation in fish, which lack parathyroid glands, differ from those in terrestrial vertebrates. The pituitary is important in hypercalcaemic regulation in fish; prolactin exerts a hypercalcaemic action in addition to its well- established hypernatraemic effect. However, alternation of plasma calcium concentration may not be the primary factor influencing prolactin secretion; changes in osmolality or sodium levels seem to be more critical for the regulation of prolactin release. Somatolactin, a putative pituitary hormone related structurally to both growth hormone and prolactin, is another possible factor responsible for hypercalcaemic regulation in fish. Exposure of rainbow trout to high-calcium environments reduces the activity of somatolactin-producing cells located in the hypophysial pars intermedia. Conversely, an increased activity of somatolactin cells is observed in low-calcium environments. Somatolactin has also been implicated in fat metabolism from comparisons of normal rainbow trout with a blue-coloured variant, which lacks most of the somatolactin cells normally present in the pituitary. Diverse functions for somatolactin, in maturation, in the stress response, in acid-base regulation and in background adaptation, have also been proposed. More detailed studies are needed to define the function of somatolactin.

scholarly journals Chromosome Analysis and Amitotic Nuclear Division in Nitella axillaris

CYTOLOGIA ◽  
1975 ◽  
Vol 40 (1) ◽  
pp. 151-156 ◽  
Author(s):  
Godfrey Roberts ◽  
James C. W. Chen
Keyword(s):  
Nuclear Division ◽  
Chromosome Analysis ◽  
Amitotic Nuclear Division

Ultrastructural investigation of an adenoma of the pituitary post mortem

1987 ◽  
Vol 45 ◽  
pp. 622-623
Author(s):  
Shirley Siew ◽  
W. C. deMendonca
Keyword(s):  
Deleterious Effect ◽  
Anterior Lobe ◽  
Definitive Diagnosis ◽  
Pars Intermedia ◽  
Post Mortem ◽  
Close Apposition ◽  
Autopsy Material ◽  
Progressive Loss ◽  
Transmission Electron ◽  
Means Of Transmission

The deleterious effect of post mortem degeneration results in a progressive loss of ultrastructural detail. This had led to reluctance (if not refusal) to examine autopsy material by means of transmission electron microscopy. Nevertheless, Johannesen has drawn attention to the fact that a sufficient amount of significant features may be preserved in order to enable the establishment of a definitive diagnosis, even on “graveyard” tissue.Routine histopathology of the autopsy organs of a woman of 78 showed the presence of a well circumscribed adenoma in the anterior lobe of the pituitary. The lesion came into close apposition to the pars intermedia. Its architecture was more compact and less vascular than that of the anterior lobe. However, there was some grouping of the cells in relation to blood vessels. The cells tended to be smaller, with a higher nucleocytoplasmic ratio. The cytoplasm showed a paucity of granules. In some of the cells, it was eosinophilic.

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