Biphasic stimulation of cellular calcium concentration by 3,5,3'-triiodothyronine in rat thymocytes

Journal Article · Tue Apr 05 00:00:00 EDT 1988 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00407a047· OSTI ID:5209009

Segal, J

3,5,3'-Triiodothyronine (T/sub 3/) produced a rapid and transient increase in /sup 45/Ca uptake and cytoplasmic free calcium concentration in rat thymocytes, which is the most rapid effect of T/sub 3/ in this system. This effect was manifested in cells suspended in medium containing 1 mM calcium. The T/sub 3/ effect on /sup 45/Ca uptake was evident at 15-30 s, reached maximum at 30-60 s, and returned to control values at 5 min. The T/sub 3/ effect on cytoplasmic free calcium concentration was seen after 30 s, reached maximum at 7 min, and returned to control values after 24 min. In cells suspended in Ca/sup 2 +/-free medium, T/sub 3/ produced a similar rapid increase in /sup 45/Ca uptake, which was sustained for at least 60 min, but T/sub 3/ failed to change cytoplasmic free calcium concentration. Alprenolol (10 ..mu..M) blocked the stimulatory effects of T/sub 3/ on these two functions in a similar fashion. From these results, the authors suggest that in rat thymocytes T/sub 3/ influences cellular calcium economy through a biphasic mechanism in which T/sub 3/ first increases calcium uptake which, in turn, if followed by a release of calcium from intracellular pool(s), resulting in a further increase in cytoplasmic free calcium concentration and the activation of Ca/sup 2 +/-regulated systems. Moreover, the present study provides further support for the postulate that in the rat thymocyte calcium serves as the first messenger for the plasma membrane-mediated stimulatory effects of T/sub 3/ on several metabolic functions.

• Research Organization: Harvard School, Boston, MA (USA)
• OSTI ID: 5209009
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 27:7; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550301* -- Cytology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
CALCIUM 45
CALCIUM COMPOUNDS
CALCIUM ISOTOPES
CHEMISTRY
DAYS LIVING RADIOISOTOPES
EVEN-ODD NUCLEI
HORMONES
INTERMEDIATE MASS NUCLEI
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
METABOLISM
NUCLEI
PEPTIDE HORMONES
RADIOISOTOPES
RATS
RODENTS
SOMATIC CELLS
THYMOCYTES
THYROID HORMONES
TRIIODOTHYRONINE
TRITIUM COMPOUNDS
UPTAKE
VERTEBRATES