Hemoglobin transitions in the bullfrog,Rana catesbeiana, during spontaneous and induced metamorphosis

✍ Scribed by Just, John J. ;Atkinson, Burr G.

• Publisher: John Wiley and Sons
• Year: 1972
• Tongue: English
• Weight: 767 KB
• Volume: 182
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1401820210

✦ Synopsis

Abstract

Electrophoretic separation of hemoglobins (Hb) during normal metamorphosis reveals larval Hb starting to disappear and adult Hb appearing during tail regression (Taylor and Kollros stage XXII). This transition is nearly complete by stage XXIV. Labeled amino acid incorporation studies demonstrate selective production of adult Hb at stage XXII, complete suppression of larval Hb by stage XXIII, and continued high levels of adult Hb production in one‐week‐old froglets. In circulating blood cells DNA synthesis begins to increase after forelimb emergence (stage XX), attains its height at stage XXII, and then declines. These results indicate that after the increase in thyroid hormone during normal metamorphosis, the first event in new blood cells is DNA synthesis. One week later these same new blood cells demonstrate a marked increase in adult Hb production.

In triiodothyronine (T~3~)‐induced metamorphosis there is measurable adult Hb production beginning 12 days after hormone treatment, indicating that thyroid hormone treatment can partially mimic the Hb transition of normal metamorphosis. This mimicry is not total because larval Hb continues to be produced and does not disappear, suggesting that other factors besides thyroid hormone may be involved in causing Hb transition during normal metamorphosis.