Effects of cysteamine administration on the in vivo incorporation of [35S]cysteine into somatostatin-14, somatostatin-28, arginine vasopressin, and oxytocin in rat hypothalamus.
The effect of cysteamine injection on the in vivo incorporation of [35S]cysteine into somatostatin-14 (SRIF-14), SRIF-28, arginine vasopressin (AVP), and oxytocin (OXT) in rat hypothalamus was studied. [35S]Cysteine was injected into the third ventricle 1 h, 4 h, or 1 week after cysteamine (300 mg/kg, sc) injection; animals were killed 4 h later. The drug was found to substantially reduce immunoreactive SRIF levels, but not OXT or AVP, 4 h after its injection. Cysteamine also caused large reductions in label incorporation into SRIF-14, SRIF-28, and OXT 1 and 4 h after drug injection. However, [35S]cysteine incorporation into AVP was increased substantially at these time points, while that into acid-precipitable protein was normal. One week after cysteamine injection, label incorporation into all hypothalamic peptides was normal. Cysteine specific activity was also measured after [35S]cysteine injection and was found to be similar in treatment and control groups. The results suggest that cysteamine inhibits the syntheses of SRIF-14, SRIF-28, and OXT and stimulates that of AVP.
Cameron
J L
JL
Fernstrom
J D
JD
D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D003543:Cysteamine / Q000494:pharmacology*; D003545:Cysteine / Q000378:metabolism*; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010121:Oxytocin / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000378:metabolism*; D053561:Somatostatin-28; D013997:Time Factors
D001127:Arginine Vasopressin; D010121:Oxytocin; D013004:Somatostatin; D003543:Cysteamine; D053561:Somatostatin-28; D003545:Cysteine