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Updated: Sep 26, 2025
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Preparation of a High-quality Primary Cell Culture from Fish Pituitaries
Published on: August 28, 2018
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Tilapia prolactin cells are thermosensitive osmoreceptors
Daniel W Woo1, G H T Malintha1, Fritzie T Celino-Brady1
1Department of Human Nutrition, Food and Animal Sciences, University of Hawai'i at Mānoa, Honolulu, Hawaii.
Summary
Temperature changes stimulate prolactin (PRL) release in tilapia via cell volume changes, similar to osmotic responses. This suggests a shared pathway for thermosensitive and osmoreceptive PRL release.
Area of Science:
- Endocrinology
- Fish Physiology
- Cell Biology
Background:
- Prolactin (PRL) cells in tilapia rostral pars distalis (RPD) release two isoforms (PRL188, PRL177) in response to hyposmotic stimuli.
- Environmental temperature fluctuations are critical for aquatic organisms.
Purpose of the Study:
- To investigate the effect of temperature changes on PRL release and mRNA levels in tilapia.
- To explore the underlying mechanisms of temperature-induced PRL release.
Main Methods:
- Perifusion of RPDs and dispersed PRL cells from Mozambique tilapia (Oreochromis mossambicus).
- Exposure to a 6°C temperature increase under isosmotic conditions.
- Measurement of PRL isoforms release, cell volume changes, and mRNA expression (prl, transient potential vanilloid 4).
Main Results:
- A 6°C temperature rise stimulated PRL188 and PRL177 release from RPDs and dispersed cells.
- Approximately 50% of dispersed PRL cells increased in volume by 8% in response to temperature, partially inhibited by mercuric chloride.
- PRL cells retained hyposmotic responsiveness after temperature exposure.
- Transient potential vanilloid 4 mRNA expression increased with temperature, while prl and prl mRNAs remained unaffected.
Conclusions:
- Thermosensitive PRL release in tilapia is partly mediated by a cell-volume-dependent pathway.
- This pathway is similar to the mechanism of osmoreceptive PRL release.
- Temperature is a significant regulator of PRL secretion in tilapia.
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