[Immunoreactive somatostatin in rat hypophysial portal blood (author's transl)]

Somatostatin levels have been determined by radioimmunoassay in hypophysial portal blood of pentobarbital-anesthetized male rats. In euthyroid rats, the mean level was 158 +/- 27 pg/ml (n = 8); somatostatin was undetectable (less than 30 pg/ml) in systemic blood of these rats. Thyroidectomy and excess of T4 did not modify the levels of somatostatin in hypophysial portal blood.