Inhibitory effects of cyproheptadine on pituitary-thyroid axis and pancreatic beta cells in rats.
AIM
To study the influences of cyproheptadine (Cyp) on the endocrine functions of pituitary-thyroid axis and pancreatic beta cells in rats.


METHODS
The effects of Cyp on functions of pituitary-thyroid axis and pancreatic beta cells were observed by radioimmunoassay, biochemical analysis, and electron microscope.


RESULTS
Cyp 2.3 mg.kg-1 ig for 10 d decreased serum thyroid stimulating hormone (TSH) from control groups (5.3 +/- 0.9) to (4.2 +/- 0.9) mU.L-1 and insulin levels from (64 +/- 8) to (50 +/- 9) kIU.L-1 (P < 0.05 and 0.01). Cyp 4.6 mg.kg-1 decreased serum TSH (3.8 +/- 0.5) mU.L-1, T3 (1.2 +/- 0.2) mmol.L-1, T4 (62 +/- 7) mmol.L-1, and insulin levels (42 +/- 8) kIU.L-1 decreased (P < 0.05 or 0.01). The retrograde changes of ultrastructure of pituitary TSH cells and pancreatic beta cells.


CONCLUSION
Cyp has an inhibiting action on endocrine functions of pituitary-thyroid axis and pancreatic beta cells in rats.