Morphological changes in the “prolactin” cell of the freshwater teleost,Xiphophorus hellerii, in salt water

✍ Scribed by Holtzman, Seymour ;Schreibman, Martin P.

• Book ID: 102893387
• Publisher: John Wiley and Sons
• Year: 1972
• Tongue: English
• Weight: 892 KB
• Volume: 180
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1401800206

✦ Synopsis

The swordtail, Xiphophorus hellerii, requires prolactin for survival in its natural freshwater habitat. Progressive cytological and ultrastructural changes of prolactin cells were observed in sibling females after a transfer from fresh water to one-third sea water for periods ranging from 18 hours to 30 days. At the light microscope level, cells became progressively smaller, displayed a decrease in acidophilia, and lost their nucleolar prominence. Electron microscopy confirmed these observations. There was a reduction of perinuclear rough endoplasmic reticulum and a progressive decrease in the size distribution of secretory granules from an average of 2800 A diameter in freshwater fish to 1700 8, for animals in dilute sea water for 30 days. Furthermore, a class of granules over 3000 A, representing approximately 45% of the granules in prolactin cells of freshwater animals, were not present after 18 hours in dilute sea water. These observations presumably reflect a diminished requirement for prolactin in a saline environment. Possible alternative explanations for the mechanisms of these changes are discussed.