Objective: 

Multiple clinical surveys on somatotropin and prolactin hormonal disorders provide evidence of modulated hemostasis. However, the precise role of those hormones in hemocoagulation is not yet clearly defined. The present study was designed to estimate the effects of somatotropin, somatostatin and prolactin on two indicators of activated blood coagulation: fibrinopeptide A, prothrombin fragment 1+2; and two hemostasis inhibitors: fibronectin and heparin cofactor II in rats.

Methods: 

Male Wistar rats (n=13) were treated in three consecutive days s.c. with somatotropin (0.2 mg/kg body mass); somatostatin (0.1 mg/kg); somatostatin applied 3 h before somatotropin in the same doses and scheme; prolactin (2 x 0.1 mg/kg) applied i.p. Fibrinopeptide A, prothrombin fragment 1+2, and fibronectin were determined by ELISA methods; heparin cofactor II – by a chromogenic kinetic method.

Results: 

Somatotropin application reduced significantly (p<0.001) fibrinopeptide A, and prothrombin fragment 1+2 and elevated (p<0.001) fibronectin and heparin cofactor II. Somatostatin applied 3 h before somatotropin and prolactin alone increased significantly fibrinopeptide A, and prothrombin fragment 1+2 in plasma and decreased (p<0.001) fibronectin and heparin cofactor II.

Conclusions: 

The results indicate the hormones examined in this study are involved in regulation of blood coagulation in the rat as: 1.) somatotopin suppresses hemocoagulation by decreasing thrombin and fibrinogen formation and activates anticoagulation via fibronectin and heparin cofactor II; 2.) somatostatin and prolactin increase the two markers of activated hemocoagulation fibrinopeptide A, and prothrombin fragment 1+2 and decrease the two anticoagulation factors; 3.) somatostatin applied in combination with somatotropin abolishes the effect of the latter and exerts its own effect which may be an evidence of endogenous somatotropin suppression.