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Biomedical subjects

C B Pert

Publications and source records attributed to C B Pert.

At least 163 records · Page 9Linked to original sources
PubMed1978

Coordinate control of corticotropin, beta-lipotropin, and beta-endorphin release in mouse pituitary cell cultures.

Hypothalamic extract stimulates the release of corticotropin (ACTH) and endorphins 2.5- to 30-fold in mouse pituitary tumor cell cultures (AtT-20/D(16v) line) and primary cell cultures from mouse anterior pituitary. ACTH and endorphin activities were measured by radioimmunoassay and immunoprecipitation. Pretreatment of tumor cell cultures with 1 muM dexamethasone reduced the stimulatory effect of the extract on release of ACTH and endorphins. Pretreatment of primary cell cultures with 10(-6) M dexamethasone reduced the stimulatory effect of both vasopressin and the extract on the release of ACTH and endorphins. Release of ACTH and endorphin was coupled in both kinds of cultures in the basal, stimulated, and inhibited states. The molecular weight forms of ACTH and endorphin in tumor cell culture medium were analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. Radioimmunoassay and immunoprecipitation show that the 13,000-dalton and 4500-dalton forms of ACTH were present in about equal amounts in medium from cultures incubated with or without hypothalamic extract for 15 min, 30 min, or 2 hr. Smaller amounts of the high molecular weight forms of ACTH (20,000- to 23,000-dalton and 31,000-dalton ACTH) were observed in the culture medium at these times. The predominant forms of endorphin released after 20 min or 3 hr of incubation had molecular weights of 31,000, 11,700 (beta-lipotropic hormone-size material) and 3500 (beta-endorphin-size material). No degradation of the forms of endorphin released into the culture medium was observed after incubating the culture medium for 1.5 hr in the absence of cells. The proportions of the different forms of endorphin and ACTH present in the culture medium resembles that seen in cell extracts.

Adrenocorticotropic Hormone↗
PubMed1978

Bomebesin: specific binding to rat brain membranes.

The binding of a radiolabeled bomebesin analogue to rat brain membranes was studied. [125I-Tyr4]Bombesin bound with high affinity (KD = 3 nM) to a single class of non-interacting sites. Binding was specific, saturable (3.8 pmol of sites/g of wet tissue), and reversible. Regional and subcellular distribution studies showed that the density of sites was 7-fold greater in the hippocampus than the medulla/pons and greater in synaptosomal fractions than in mitochondrial or nuclear fractions. The abilities of numerous bombesin analogues to induce hypothermia and to inhibit [125I-Tyr4]bombesin-binding activity correlate well. Numerous amino acid residues near the CONH2-terminal are required for high-affinity binding and biological potency.

Animals↗
PubMed1976

(D-Ala2)-Met-enkephalinamide: a potent, long-lasting synthetic pentapeptide analgesic.

[D-Ala2]-Met-enkephalinamide (DALA), a synthetic enkephalin analog designed by in vitro analysis, binds to opiate receptors almost as tightly as methionine-enkephalin. Since it is not susceptible to degradation by brain enzymes, low doses (5 to 10 micrograms) cause profound, long-lasting, morphine-like analgesia when microinjected into rat brain.

Analgesia↗
PubMed1976

Correlation of opiate receptor affinity with analgetic effects of meperidine homologues.

The affinity for opiate receptor sites in brain tissue in a series of N-substituted meperidine homologues has been compared with the analgetic potency of these compounds in mice. There is a good correlation between affinity for opiate receptor binding sites assayed in the presence of sodium and analgetic potency for homologues whose N-substituent has six or fewer carbons. The apparent discrepancy between the weak affinity of these drugs for opiate receptors and their fairly potent analgetic effects in vivo can be explained by meperidine's efficient penetration into brain.

Analgesics, Opioid↗
PubMed1976

Opiate receptor: autoradiographic localization in rat brain.

Opiate receptor sites in rat brain can be labeled in vivo by [3H]diprenorphine, a potent opiate antagoinst. Using techniques to minimize diffusion in fresh, frozen, unfixed brain, we have localized [3H]diprenorphine by autoradiography to visualize the distribution of opiate receptors. Silver grains indicative of the binding of labeled [3H]diprenorphine are discretely localized in numerous areas of the brain with very high densities in the locus coeruleus, the substantia gelatinosa of the spinal cord, and in clusters within the caudate-putamen, amygdala, and parts of the periventricular gray matter.

Animals↗
PubMed1976

Isolation of a novel endogenous opiate analgesic from human blood.

Based upon its ability to inhibit opiate receptor binding, a low-molecular-weight substance (600) has been isolated from human plasma by extraction into butanol and ion exchange, molecular sieve, and thin-layer chromatography. When this substance, termed anodynin, is microinjected into rat periaqueductal gray matter, it causes a profound, long-lasting analgesia which is prevented by prior injection of the opiate antagonist naloxone. Anodynin (opiate receptor binding material) levels in serum from hypophysectomized rats are less than 5% of values obtained in sham-operated controls. Anodynin differs from enkephalin, a morphine-like peptide isolated from brain, in its sensitivity to enzymatic loss of opiate receptor inhibitory potency, thin-layer chromatographic mobility, and behavioral effects. Anodynin might be a hormone that acts on peripheral opiate receptors in the classical manner, but might also, due to its lipophilic nature and small size, penetrate into the brain to produce centrally mediated behavioral effects.

Analgesia↗
PubMed1976

Opiate receptor interactions of benzomorphans in rat brain homogenates.

Minor structural variations of benzomorphans opiates are associated with striking, unpredictable shifts in the relative extent of agonist or antagonist properties in vivo. The relative abilities of a number of benzomorphans in inhibit 3H-naloxone binding in the absence and presence of sodium in vitro show some correlations with their pharmacologic properties in vivo, although distinct exceptions exist. The ability of opiate agonists to inhibit 3H-naloxone binding is greatly reduced by sodium, while pure antagonists are affected very little, if at all, and mixed agonist-antagonist benzomorphans display an intermediate response.

Animals↗