Pituitary gene expression of somatolactin, prolactin, and growth hormone during Atlantic salmon parr-smolt transformation

Thorleifur Ágústsson, Kristina Sundell, Tatsuya Sakamoto, Masaaki Ando, Björn Thrandur Björnsson

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Somatolactin (SL), prolactin (PRL) and growth hormone (GH) belong to the same family of adenohypophyseal hormones. In fish, these hormones have all been linked to several important physiological functions. During salmon smoltification, GH has an important role in stimulating growth and improving hypoosmoregulatory ability. The role of PRL in fish osmoregulation has mostly been linked to survival in fresh water (FW), whereas the physiological functions of SL is less clear, having been linked to reproduction, stress, Ca-regulation and acid - base balance. To obtain more information on the roles and interactions of these hormones during the parr - smolt transformation, juvenile Atlantic salmon in FW were sampled from early-February until late-June. Approximately every 2 weeks, fish were sacrificed and pituitaries sampled for assessment of SL, PRL, and GH mRNA. In addition, fish were transferred to seawater (SW) in late-May, and sampled after 1 and 4 weeks in SW. Somatolactin mRNA expression did not change during the parr - smolt transformation of the Atlantic salmon, but increased transiently during the first week in SW, a response which may be correlated to stress and/or Ca-balance. PRL and GH mRNA expression increased transiently during the latter part of the parr - smolt transformation of Atlantic salmon. Following SW entry, the PRL mRNA expression decreased, while GH mRNA expression increased further. This indicates that PRL is of importance during the parr - smolt transformation of the Atlantic salmon, probably by counteracting the hypoosmoregulatory effects of GH and cortisol, allowing the fish to maintain osmotic balance during the smoltification process.

Original languageEnglish
Pages (from-to)229-238
Number of pages10
JournalAquaculture
Volume222
Issue number1-4
DOIs
Publication statusPublished - May 26 2003
Externally publishedYes

Keywords

  • Gene expression
  • Growth hormone (GH)
  • In vitro
  • Prolactin (PRL)
  • Salmo salar
  • Smoltification
  • Somatolactin (SL)

ASJC Scopus subject areas

  • Aquatic Science

Fingerprint Dive into the research topics of 'Pituitary gene expression of somatolactin, prolactin, and growth hormone during Atlantic salmon parr-smolt transformation'. Together they form a unique fingerprint.

  • Cite this