Growth hormone and somatostatin treatment change 5-HT1 receptor activity.
1. The effect of 10 day treatment with growth hormone (GH) (1 mg/kg body weight/day) and somatostatin (SRIF) (0.25 mg/kg body weight/day) subcutaneously on the activity of 5-HT1 receptors in rat hypothalamic, pituitary and cerebral cortical membrane fractions was studied using [3H]5-HT as radioligand. 2. The administration of GH and SRIF significantly decreased the 5-HT1 binding capacity and affinity in the hypothalamus. 3. In the pituitary the 5-HT1 receptor activity was also significantly decreased after both hormonal applications. 4. In the cerebral cortex the 5-HT1 receptor affinity was significantly decreased and the binding capacity was increased. 5. The results obtained indicate that GH and SRIF decrease 5-HT1 receptor activity. 5-HT1 receptors are possibly involved in the 5-HT controlled GH feedback autoregulation mediated by SRIF.
Institute of Endocrinology and Gerontology, Bulgarian Medical Academy, Sofia.
J
J
Popova
E
E
Ivanova
T
T
Tosheva
N
N
Iavorska
D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D013006:Growth Hormone / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects*; D013004:Somatostatin / Q000494:pharmacology*; D009435:Synaptic Transmission / Q000187:drug effects
D011985:Receptors, Serotonin; D013004:Somatostatin; D013006:Growth Hormone