Influence of L-triiodothyronine on rat somatotroph cells.
The L-Triiodothyronine (L-T3) has a direct influence on the population of somatotrophs in rat pituitary gland. This effect is dose-dependent and induces both proliferation of somatotrophs and striking changes in the synthesis and secretion of growth hormone (GH). Daily injections of 5 micrograms L-T3 for 7 days increased significantly the synthesis and storage of GH in pituitary gland, but the GH release was partially blocked. By contrast, injections of 10 micrograms L-T3 promote rapid synthesis and secretion of GH with removal of the cytoplasmic stores of the hormone and a consequent rise of serum levels. A close correlation was found between levels of stimulation and proliferation or retrogression of lactotroph cell population.
Bonaterra
M
M
Centro de Microscopía Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina.
Maldonado
C A
CA
Aoki
A
A
Torres
A I
AI
D000818:Animals; D013006:Growth Hormone / Q000096:biosynthesis / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008854:Microscopy, Electron; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014284:Triiodothyronine / Q000008:administration & dosage / Q000494:pharmacology*
D014284:Triiodothyronine; D013006:Growth Hormone