Regulation of ovarian recrudescence: Different effects of corticotropin in small and large female lizards,Anolis carolinensis

✍ Scribed by Summers, Cleff H.

• Book ID: 102893175
• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 738 KB
• Volume: 271
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402710310

✦ Synopsis

Abstract

Subcutaneous injection of 50 mU of ovine adrenocorticotropic hormone (ACTH) stimulates an increase in plasma corticosterone in Anolis carolinensis, after 30 min equivalent to maximum levels of stress‐induced plasma corticosterone. Plasma corticosterone returned to noninjection levels by 4 h. Injection of 50 mU ACTH, daily at 1630, into female A. carolinensis treated with stimulatory temperature and light, effected ovarian recrudescence; however, the effect depended upon the size of the lizard. Ovarian growth in small lizards (≥2.6 g) was inhibited by ACTH. In these animals ovaries regressed in size and oviducts remained quiescent. In larger females (<2.6 g) ovarian recrudescence continued in spite of ACTH administration and the consequent stimulation of higher levels of plasma corticosterone. Oviducts were significantly heavier in this group as well, indicating that ovaries were not only larger and heavier, but were secreting estrogens as well. The results of these experiments suggest that differently sized females of this species respond to hormones of the adrenal axis differently, and perhaps to stress as well. Specifically, Whereas ACTH administration inhibits ovarian growth in small anoles as it does in other vertebrates, it appears to have no effect or to enhance ovarian growth in large female A. carolinensis. © 1995 Wiley‐Liss, Inc.