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Biomedical subjects

R Guillemin

Publications and source records attributed to R Guillemin.

At least 19 recordsLinked to original sources
PubMed1979

Perinatal development of the endorphin- and enkephalin-containing systems in the rat brain.

Radioimmunoassay and microdissection procedures were used to study the perinatal development of the endorphin- and enkephalin-containing systems in the rat brain. In contrast to values reported on adult rat, endorphin levels are much higher than enkephalin levels on embryonic day 16. The highest endorphin values are found in the diencephalon, midline telencephalon and medulla-midbrain regions. Perinatally, enkephalin content increases at a faster rate than endorphin in all brain regions, producing a marked drop of the endorphin/enkephalin ratios. Between postnatal days 6 and 25, both endorphin and enkephalin levels increase, approaching their adult distribution pattern. No correlation was found between regional distributions or rates of increase of endorphin and enkephalin in any of these developmental stages, suggesting that the two peptide systems develop independently from each other.

Age Factors↗
PubMed1979

[Gonadostatin and gonadocrinin, polypeptides of ovarian origin with hypophysiotropic activity].

Crude acetic acid extract of Rat ovaries pretreated with pregnant mare serum (PMSG) contains native peptides with two types of separable biological activities: one, molecular weight greater than 10,000 dalton inhibits the secretion of both LH and FSH as stimulated by luteinizing hormone releasing factor (LRF) in a pituitary monolayer culture system and is referred to as gonadostatin; the other, less than 3,500 dalton, stimulates the secretion of gonadotropins and is designated as gonadocrinin. The biological activities of ovarian gonadocrinin can be competitively inhibited by an LRF-analog-antagonist, D-Phe2, D-Trp6-LRF. These ovarian peptides may participate in physiological control of pituitary LH/FSH secretion.

Animals↗
PubMed1979

Partially modified retro-inverso-enkephalinamides: topochemical long-acting analogs in vitro and in vivo.

The synthesis of four enkephalinamide analogs is described in which the peptide bond between residues 4 and 5 is reversed with or without simultaneous reversal of the carboxyl-terminal amide bond. These so-called partially modified retro-inverso-isomers are new, potent, topochemical analogs of the enkephalins. Tests, both in vitro and in vivo, have shown that these analogs are considerably longer acting than any previously studied enkephalins. Thus, partial reversal of the peptide bonds of the backbone can result in peptides with enhanced activity compared to a parent compound, provide that the structural complementarity of both the side chains and end groups are conserved.

Animals↗
PubMed1979

Stimulation of human periaqueductal gray for pain relief increases immunoreactive beta-endorphin in ventricular fluid.

Immunoreactive beta-endorphin was measured in the ventricular fluid of six patients with chronic pain. Stimulation of the periaqueductal gray matter in three patients with pain of peripheral origin resulted in significant increases (50 to 300 percent) in the concentration of ventricular immunoreactive beta-endorphin. In three other patients suffering deafferentation dysesthesia, stimulation of the posterior limb of the internal capsule did not alter the concentration of this peptide. These results provide evidence of the release of human immunoreactive beta-endorphin in vivo and suggest that naloxone-reversible pain relief achieved by stimulation of the periaqueductal gray matter may be in part mediated by the activation of beta-endorphin-rich diencephalic areas.

Aged↗
PubMed1979

Opioid peptides and alpha-melanocyte-stimulating hormone in genetically obese (ob/ob) mice during development.

Compared to littermate controls (C57BL/6J ob/?), body weights of genetically obese (ob/ob) mice are significantly higher at 1-6 months of age; the greatest percentage weight gain of the ob/ob group occurs during the first 3 months of life. Levels of pituitary immunoreactive beta-endorphin and immunoreactive alpha-melanocyte-stimulating hormone are also significantly elevated in ob/ob animals compared to controls. However, these pharmacological differences only emerge at 4-6 months of age--3 months after the appearance of obesity. High levels of immunoreactive endorphin in the pituitary are, therefore, more likely to be a consequence than a cause of obesity. Furthermore, numerous other neurologic abnormalities, which may or may not play a role in the obesity syndrome, are evident in ob/ob mice. Compared to controls, ob/ob total brain, hypothalamus, and pituitary weights are 11%, 16%, and 23% less, respectively. Levels of immunoreactive Leu5-enkephalin in pars nervous are also 200% higher in ob/ob mice; this increase is apparent at 1-6 months of age and is highly correlated with changes in body weight.

Aging↗
PubMed1979

Dried Staphylococcus aureus as a rapid immunological separating agent in radioimmunoassays.

A rapid (less than or equal to 60 seconds) immunological separation of antigen-antibody complexes from free antigen has been developed in radioimmunoassays (RIAs) of luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL) and beta-endorphin by using suspensions of dried Staphylococcus aureus rich in protein-A. In the systems tested parallel dose-response curves were obtained for protein-A and second antibody precipitations. The sensitivity of the protein-A method is equal to or higher than that of second antibody method. Tissue culture medium and serum hormone levels measured with RIAs using protein-A are similar to those detected with double antibody methods. The technique may be of general use in all RIAs utilizing antisera from species whose IgG are known to be bound by protein-A.

Antigen-Antibody Complex↗