Peripheral plasma somatostatin-like immunoreactive responses to insulin hypoglycemia and a mixed meal in healthy subjects and in noninsulin-dependent maturity-onset diabetics.

We have measured peripheral plasma immunoreactive somatostatin (SRIF-LI) in 10 healthy subjects and 10 noninsulin-dependent maturity-onset diabetics (NIDDM). The mean (+/-SE) basal level of SRIF-LI in NIDDMs of 185 +/- 27 was similar to that of 174 +/- 23.5 pg/ml in age-, weight-, and sex-matched healthy subjects.

Substance P release from rat hypothalamus and spinal cord.

A specific and sensitive radioimmunoassay for substance P has been developed to study the release of immunoreactive substance P from incubated rat hypothalamus and rat spinal cord in vitro. Release was significantly increased in the presence of two depolarizing stimuli (56 mM KCl and 75 microM veratrine) and was calcium-dependent. The released immunoreactive material diluted in parallel with synthetic substance P and showed close identity on Sephadex chromatography.

Failure of somatostatin to inhibit epinephrine (adrenaline)-stimulated hepatic glucose output in vitro.

Somatostatin has no effect on epinephrine (adrenaline)-stimulated hepatic glucose output in the isolated perfused rat liver, which suggests that the peptide does not inhibit the phosphorylase enzyme system.

Tissue and serum somatostatin-like immunoreactivity in lean and obese Zucker rats.

Tissue and serum somatostatin levels were measured in genetically lean and obese Zucker rats. Immunoreactive somatostatin content was decreased in three central nervous system regions (hypothalamus, septum and preoptic area and thalamus) of obese rats but was increased in cerebral cortex. No differences were observed in antral or colonic somatostatin content but obese animals had significantly elevated pancreatic levels.