The annual ovarian cycle of Chrysemys picta: Correlated changes in plasma steroids and parameters of vitellogenesis

Ian P. Callard, Valentine Lance, Adele R. Salhanick, David Barad

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172 Scopus citations

Abstract

The annual ovarian cycle of the painted turtle, Chrysemys picta, is described and correlated with plasma changes in parameters of vitellogenesis (protein, calcium, and cholesterol) and steroids (progesterone, testosterone, and estradiol). Three major classes of ovarian follicles were identified at all times of the year, and ovarian growth was confined to two major phases. The first, in which vitellogenesis was most active, occurred in the fall, after a postovulatory period of follicular atresia. This was followed by a winter period of inactivity and the spring ovarian growth phase, in which the follicles rapidly reached ovulatory size. Ovulation occurs during mid-May to mid-June, and a period of follicular atresia follows oviposition. Marked changes in all three plasma steroids occur during the periovulatory period, increasing sharply prior to or around the time of ovulation, and falling sharply thereafter. Correlated with the fall period of ovarian recrudescence, smaller peaks of testosterone and estradiol, but not progesterone, occur. These data are discussed with regard to possible control of the chelonian ovarian cycle.

Original languageEnglish
Pages (from-to)245-257
Number of pages13
JournalGeneral and Comparative Endocrinology
Volume35
Issue number3
DOIs
StatePublished - Jul 1978
Externally publishedYes

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