Effect of centrally administered somatostatin on pituitary thyrotropes in male rats.
The effects of intracerebroventricularly administered somatostatin (SRIH-14 or -28) on growth and function of pituitary thyrotropes (TSH-cells) were examined in adult male Wistar rats. The animals were implanted with an intracerebroventricular cannula and after a recovery period, administered three 1 microg doses of SRIH-14 or -28 dissolved in 5 microl saline every second day. Controls were treated in the same way with the same volume of saline only. TSH-producing cells were studied using the peroxidase-antiperoxidase immunohistochemical procedure. Blood samples were collected for hormone (TSH) analyses 5 days after the last injection. Both SRIH-treatments significantly decreased (p < 0.05) all morphometric parameters obtained for TSH-cells in comparison with controls. The volume of TSH-cells decreased by 27%, nuclei by 44% and volume density by 33% in animals treated with SRIH-14. In animals treated with SRIH-28, these parameters were also significantly decreased (p < 0.05) (22%, 31%, and 25% respectively) compared to control rats. Serum concentrations of TSH were significantly decreased (p < 0.05) by 15% in SRIH-14- and by 12% in SRIH-28-treated animals in comparison with the controls. These observations suggest that centrally administered SRIH- 14 or -28 is specifically involved in the control of growth and secretory activity of TSH cells.
Milosević
V
V
Department of Cytology, Institute for Biological Research Sinisa Stanković, Yugoslavia.
Sekulić
M
M
Brkić
B
B
Lovren
M
M
Starcević
V
V
D000818:Animals; D007276:Injections, Intraventricular; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013004:Somatostatin / Q000008:administration & dosage / Q000494:pharmacology*; D013972:Thyrotropin / Q000378:metabolism*
D013004:Somatostatin; D013972:Thyrotropin