Quantitative magnetic resonance imaging of estradiol-induced pituitary hyperplasia in rats.

Magnetic resonance imaging (MRI) has been used for the determination in vivo of rat pituitary size. In midsagittal T2-weighted sections the pituitary, having a lower T2 value than the surrounding tissue, was visible with pronounced contrast. The size has been estimated by pixel counting.

The effect of a somatostatin analogue (SMS 201-995, Sandostatin) on the concentration of phosphoribosyl pyrophosphate and the activity of the pentose phosphate pathway in the early renal hypertrophy of experimental diabetes in the rat.

The effect of a long-acting somatostatin analogue on the acute renal hypertrophy following induction of experimental diabetes in the rat has been studied. The kidney weight increase occurring at 2 and 7 days after alloxan injection was significantly lower in the diabetic group receiving somatostatin. Similarly, the previously reported increase in glucose-6-phosphate dehydrogenase (EC 1.

Chemistry and pharmacology of SMS 201-995, a long-acting octapeptide analogue of somatostatin.

Starting from a hypothetical conformation of natural somatostatin and a knowledge of the minimal fragment needed for biological activity, a process of rational design and lead optimization has led to the potent, selective, and long-acting analogue SMS 201-995, (formula: see text) which selectively inhibits growth hormone secretion in several animal species for up to 6 h after subcutaneous application. In the rat, SMS inhibits GH, insulin, and glucagon 70, 3, and 23 times more potently than SRIF, resulting in GH/insulin and GH/glucagon selectivities of 20 and 3, respectively. The compound has been shown to inhibit growth of transplantable insulinomas in hamsters and to label selectively a subset of somatostatin receptors in the rat cortex.

SMS 201-995: a very potent and selective octapeptide analogue of somatostatin with prolonged action.

Stepwise modification of a conformationally stabilised analogue of the fragment of somatostatin which had been thought to be essential biologically active moiety has enabled us to synthesise the analogue H-(D) Phe-Cys-Phe-(D) Trp-Lys-Thr-Cys-Thr(ol) code-named SMS 201-995, which in vitro is three times more potent than the native hormone in inhibiting the secretion of growth hormone, which is highly resistant to degradation by pure enzymes and by tissue homogenates, which in vivo in rat and rhesus monkey is (depending on test system) at least 20 times more active than somatostatin, which is much longer acting, and which moreover in both species is much more selective in inhibiting the secretion of growth hormone than that of insulin. The compound is active by several routes of administration including the oral, is well tolerated both in laboratory animals and in man, and is currently undergoing preliminary clinical trial.

Two novel prolactin release-inhibiting 8 alpha-amino-ergolines.

Prolactin secretion inhibition and changes in striatal dopamine metabolism in rats were compared after the administration of 8 alpha-amino-ergoline CH 29-717 and 2 derivates. CQ 32-084 was similar to but less potent than CH 29-717, while 32-085, the l-methyl derivative, showed delayed dopaminomimetic effects.