The somatostatin analog, octreotide, causes accumulation of growth hormone-releasing hormone and depletion of angiotensin in the rat hypothalamus.
Rats were injected intracerebroventricularly with the somatostatin analog, octreotide (OCT; 0.1 microg) or vehicle, and hypothalamic contents of growth hormone-releasing hormone (GHRH), angiotensin II, and vasopressin were determined 10 min, 1, 3 and 6 h post-injection. OCT elicited an immediate release of angiotensin II (10 min) and a rise in GHRH content (1 h) followed by gradual (1-6 h) depletion of accumulated GHRH. Hypothalamic vasopressin was not altered but decreases in pituitary vasopressin occurred 10 min post-injection. The OCT-induced alterations in GHRH may explain previously reported changes in sleep whereas angiotensin may mediate OCT-induced drinking, vasopressin secretion and rises in blood pressure via sst2 somatostatin receptors.
Gardi
J
J
Endocrine Unit, A. Szent-Györgyi Medical Center, University of Szeged, 6720, Szeged, Hungary.
Szentirmai
E
E
Hajdu
I
I
Obal
F
F
Krueger
J M
JM
D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D013007:Growth Hormone-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D007276:Injections, Intraventricular; D008297:Male; D015282:Octreotide / Q000494:pharmacology*; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D014667:Vasopressins / Q000378:metabolism
D014667:Vasopressins; D000804:Angiotensin II; D013007:Growth Hormone-Releasing Hormone; D015282:Octreotide