Immunocytochemical localization of insulin and somatostatin in the endocrine pancreas of the sea lamprey Petromyzon marinus L., at various stages of its life cycle

1986 ◽  
Vol 243 (3) ◽  
Author(s):  
W.M. Elliott ◽  
J.H. Youson
Keyword(s):  
Life Cycle ◽  
Endocrine Pancreas ◽  
Petromyzon Marinus ◽  
Sea Lamprey ◽  
Immunocytochemical Localization

Observations on the opisthonephric kidney of the sea lamprey of the Great Lakes, Petromyzon marinus L., at various stages during the life cycle

1970 ◽  
Vol 48 (6) ◽  
pp. 1313-1316 ◽  
Author(s):  
John H. Youson
Keyword(s):  
Life Cycle ◽  
Great Lakes ◽  
Amorphous Material ◽  
Petromyzon Marinus ◽  
Kidney Tissue ◽  
Adult Life ◽  
Sea Lamprey ◽  
The Other ◽  
Larval Life ◽  
Adult Kidney

The kidneys at all stages consist of renal corpuscles, tubules, and an archinephric duct. The kidney of the ammocoete does not contribute to the formation of the adult kidney for at transformation a new kidney is formed. Degeneration of kidney tissue occurs at four stages: in the anterior regions throughout larval life; in the entire ammocoete kidney at transformation; in the anterior regions throughout adult life; in the entire kidney during the spawning migration. Large quantities of amorphous material appear in the interstitium during anterior degeneration of the adult. The other stages involve necrosis followed by the invasion of phagocytes.

scholarly journals THE METAMORPHOSIS OF VISUAL SYSTEMS IN THE SEA LAMPREY

1957 ◽  
Vol 40 (6) ◽  
pp. 901-914 ◽  
Author(s):  
George Wald
Keyword(s):  
Life Cycle ◽  
Fresh Water ◽  
Petromyzon Marinus ◽  
Sea Lamprey ◽  
Mature Adult ◽  
Visual Systems ◽  
General Association ◽  
Vitamin A2 ◽  
Sexually Mature ◽  
Living Group

The life cycle of the sea lamprey, Petromyzon marinus, includes two metamorphoses. At the end of a period spent as a blind larva, buried in the mud of streams, a first metamorphosis prepares it to migrate downstream to the sea or a lake for its growth phase. Then, following a second metamorphosis, it migrates upstream as a sexually mature adult to spawn and die. The downstream migrants have a visual system based upon rhodopsin and vitamin A1, whereas that of the upstream migrants is based upon porphyropsin and vitamin A2. The livers contain vitamin A1 at all stages. The sea lamprey therefore exhibits a metamorphosis of visual systems, like those observed earlier among amphibia. The presence of porphyropsin in this member of the most primitive living group of vertebrates, as in fishes and amphibia, supports the notion that porphyropsin may have been the primitive vertebrate visual pigment. Its association with fresh water existence throughout this range of organisms also is consistent with the view that the vertebrate stock originated in fresh water. The observation that in the life cycle of the lamprey rhodopsin precedes porphyropsin is not at variance with the idea that porphyropsin is the more primitive pigment, since this change is part of the second metamorphosis, marking the return to the original environment. The observation that in lampreys, fishes, and amphibia, porphyropsin maintains the same general association with fresh water, and rhodopsin with marine and terrestrial habit, suggests that a single genetic mechanism may govern this association throughout this wide span of organisms.

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