2000 Fiscal Year Final Research Report Summary

EFFECT OF THYROID HORMONES ON APOPTOSIS IN CHICK SKELETAL MUSCLE CELLS

Research Project

Project/Area Number	10660273
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Applied animal science
Research Institution	KAGOSHIMA UNIVERSITY
Principal Investigator	HAYASHI Kunioki FACULTY OF AGRICULTURE, KAGOSHIMA UNIVERSITY, PROFESSOR, 農学部, 教授 (80041656)
Co-Investigator(Kenkyū-buntansha)	OHTSUKA Akira FACULTY OF AGRICULTURE, KAGOSHIMA UNIVERSITY, ASSOCIATE PROFESSOR, 農学部, 助教授 (10233173)
Project Period (FY)	1998 – 2000
Keywords	MUSCLE / THYROID HORMONE / APOPTOSIS
Research Abstract	Myoblasts were isolated from thigh muscles of 13-day-old chick embryos by digestion with dispase. After the cells were incubated for 24 hours, thyroid hormones -thyroxine (T4) and triiodothyronine (T3) - were added in the medium and the incubation was continued for 6 days. Cell differentiation was increased by both T4 and T3 while cell proliferation was inhibited by T3 but not by T4. Furthermore, muscle protein breakdown wasincreased and DNA content was decreased by T3 but not by T4. Thus DNA cleavage and fragmentation as indices apoptosis were measured and shown that apoptosis was induced by T3 but not by T4. Proteasome and cathepsin activities were also measured to show the relationship with apoptosis. The results indicated a possible relationship between apoptosis and protease activity. The present study shows that T4 is an active hormone but it's role is different from that of T3.

(2 results)