Plasma immunoreactive calcitonin in the frog (Rana pipiens)
Original Research Article
• Comparative Biochemistry and Physiology Part A: Physiology, Volume 88, Issue 4, 1987, Pages 701-705
• Douglas R Robertson
•
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Abstract
1. Plasma immunoreactive calcitonin (iCT) and ionic calcium ([Ca]i) were measured in intact frogs (Rana pipiens) within complete 24 hr light-dark cycles over an 18 month period.
2. Plasma iCT exhibits an annual periodicity about the annual mean of 10.0ng/ml, with an amplitude of 5.4 ng/ml that peaks in October.
3. Within an annual cycle, a significant inverse association exists between the basal monthly levels of plasma iCT and [Ca]i for animals maintained in freshwater control conditions.
4. When subjected to a high calcium environment during the latter half of the year, plasma [Ca]i and iCT were elevated above control levels but exhibited independent cyclic patterns.
5. A distinct seasonal response of increased iCT in a high calcium environment may be related to the secretory activity of the ultimobranchial glands and physiological responsiveness to other calcémie hormones; e.g. parathyroid hormone and vitamin D.