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Hypo- and hypercalcemic peptides in fish pituitary glands
R A Fraser1, T Kaneko, P K Pang
1Department of Physiology, University of Alberta, Edmonton, Canada.
The American Journal of Physiology
|March 1, 1991
Summary
Researchers found parathyroid hormone (PTH) and related peptides in Coho salmon pituitary glands, indicating these hormones play a role in fish calcium regulation and suggesting an ancient evolutionary origin for these peptides.
Area of Science:
- Endocrinology
- Comparative Physiology
- Evolutionary Biology
Background:
- The fish pituitary gland is known to regulate calcium metabolism.
- The presence and function of parathyroid hormone (PTH) and related peptides in fish endocrine systems are not fully understood.
Purpose of the Study:
- To investigate the presence and localization of immunoreactive parathyroid hormone (irPTH), PTH-related peptide (PTHrp), and stanniocalcin-like peptides in teleost pituitary glands.
- To explore the evolutionary origins of PTH and PTHrp.
Main Methods:
- Immunoreactivity detection of irPTH, PTHrp, and stanniocalcin-like peptides in Coho salmon pituitary glands.
- High-performance liquid chromatography (HPLC) for peptide purification and separation.
- Immunocytochemistry for localizing stanniocalcin in platyfish brain.
Main Results:
- Distinct peptide fractions coeluting with pure PTH, PTHrp, and stanniocalcin were identified in Coho salmon pituitary glands.
- Stanniocalcin was localized in the neurohypophysis and preoptic area of the platyfish brain.
- The study demonstrates the presence of both hyper- and hypocalcemic peptides in teleost pituitary glands.
Conclusions:
- Teleost pituitary glands contain peptides involved in calcium regulation, including PTH and PTHrp.
- The presence of PTHrp in fish pituitary glands is reported for the first time outside of mammals.
- These findings suggest an early evolutionary divergence of PTH and PTHrp from a common ancestral gene.