Transient expression pattern of prolactin in Sparus aurata

Area of Science:

• Endocrinology
• Fish Biology
• Molecular Biology

Background:

• Prolactin (PRL) is a key hormone involved in reproduction and development across vertebrates.
• Its role in fish development, particularly in commercially important species like gilthead sea bream (Sparus aurata), requires further elucidation.
• Understanding PRL gene expression is crucial for aquaculture and developmental biology.

Purpose of the Study:

• To investigate the expression patterns of the prolactin (PRL) gene during the early development of gilthead sea bream (Sparus aurata).
• To determine the localization of PRL-producing cells within the sea bream pituitary gland.
• To explore the potential involvement of PRL in the asynchronous growth observed in cultivated gilthead sea bream.

Main Methods:

• Reverse transcription-polymerase chain reaction (RT-PCR) was employed to detect PRL mRNA.
• In situ hybridization was used to identify the spatial expression and localization of PRL transcripts.
• PRL cell distribution was analyzed across different sizes of juvenile gilthead sea bream.

Main Results:

• PRL mRNA was detectable from the second day of the larval stage in Sparus aurata.
• PRL transcripts were localized to adenohypophysial cells, indicating pituitary specificity, from four days post-hatching.
• No significant differences in PRL cell distribution were observed among juvenile sea bream of varying sizes.

Conclusions:

• The transcription of the prolactin gene is an early developmental event in gilthead sea bream.
• PRL expression is specific to the pituitary gland during early sea bream development.
• Asynchronous growth in cultivated gilthead sea bream is unlikely to be caused by variations in PRL cell distribution.