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C W Simpson

Publications and source records attributed to C W Simpson.

6 recordsLinked to original sources
PubMed1979

Pituitary function testing in amenorrhea-galactorrhea-hyperprolactinemia.

Fifteen patients, age 16 to 55, presented with amenorrhea-galactorrhea-hyperprolactinemia. Pituitary function was evaluated by bolus injections of insulin, luteinizing hormone-releasing hormone (LHRH), and thyrotropin-releasing hormone (TRH) in 13 and by LHRH and TRH in 2. Responses to growth hormone (GH), thyroid-stimulating hormone (TSH), cortisol (F), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin were measured. GH, TSH, and F responses were normal in most cases. LH responses were decreased (P less than 0.025) in patients with abnormal sellar tomography, whereas FSH responses tended to decrease with elevated prolactin levels. Prolactin responses were absent in five of the seven cases which could be evaluated. The clinical value of such testing appears to be limited to an individualized basis, although some prognosis of ovulatory response to bromocriptine therapy may be obtained from the gonadotropin response.

Adolescent↗
PubMedDate not supplied

Dopamine release within forebrain sites perfused with tetrahydroisoquinolines or tryptoline in the rat.

The localized effect of amine-aldehyde condensation products on the endogenous release of dopamine (DA) was examined in dopaminergic-rich areas of the brain. In the unanesthetized rat, dopaminergic stores were labeled by 14C-dopamine (1.0 microCi) microinjected in a volume of 1.0 microliters into the caudate nucleus, tuberculum olfactorium, nucleus accumbens or other contiguous sites within the ventral forebrain. Subsequently, each labeled site was locally perfused with an artificial CSF, by means of push-pull cannulae, at a rate of 25.0 microliters per min. Two tetrahydroisoquinolines, tetrahydropapaveroline and 4,6,7-TH-tetrahydroisoquinoline, as well as the tetrahydro-beta-carboline, tryptoline, significantly enhanced the release of 14C-DA when each alkaloid metabolite was perfused in a concentration of 250 nanograms per min. Tetrahydroisoquinoline was without effect on the local kinetics of 14C-DA, whereas salsolinol had an intermediary action on DA release. These findings suggest that an alkaloid conjugate when given in the cerebral ventricle could exert its central effects by way of a dopaminergic mechanism in the telencephalon.

Animals↗
PubMedDate not supplied

Disulfiram alters dopamine metabolism at sites in rat's forebrain as detected by push-pull perfusions.

The effect of tetraethylthiuramdisulfide (disulfiram) on the catabolism of dopamine within discrete regions of the brain was investigated in the unrestrained rat. After a guide cannula had been implanted stereotaxically, a given subcortical site was radiolabeled with 14C-dopamine (DA) by microinjecting 2.0 mu Ci in 2.0 microliters. Successive push-pull perfusates collected from each tissue were assayed by paper electrophoresis for the separation of DA metabolites. When disulfiram, a potent aldehyde dehydrogenase (ALDH) inhibitor, was given intragastrically in a clinically efficacious dose of 200 mg, the formation of the acids DOPAC and HVA was inhibited within perfusates of the caudate nucleus and nucleus accumbens. However, following disulfiram treatment, the proportion of alcohol metabolites did not differ from the control level in the untreated rat. The level of ALDH decreased by approximately 50% in these subcortical nuclei following the inhibition of the enzyme by disulfiram. Conversely, in samples of perfusate obtained from 14C-labeled sites within inferofrontal cortex, periform cortex, diagonal band of Broca, lateral-posterior caudate nucleus, tuberculum olfactorium, lateral olfactory tract or the olfactory nuclear complex, the proportion of DA metabolites remained stable. Generally, a low rate of deamination of the exogenously injected DA occurred within perfusion sites in the ventrobasal forebrain, whereas an intermediate rate of deamination was noted in samples collected at more dorsal loci. Thus, clearcut regional differences in DA catabolism occur in the brain of the living animal, which may depend upon the characteristics of the dopaminergic-rich area of the rat's brain.

Alcohols↗
PubMedDate not supplied

Serum thyroxin levels during hyperthermia evoked in the monkey by intrahypothalamic injection of PGE1, 5-HT or pyrogen.

Serotonin (5-HT), prostaglandin E1 (PGE1) or a bacterial pyrogen (E. coli or S. typhosa) was microinjected in a volume of 1.0--1.5 microliter into the hypothalamus of the unanesthetized monkey to evoke a long-term hyperthermia. Samples of venous blood collected every 15 min, before, during and after each fever were analyzed by radioimmunoassay for plasma thyroxin levels. There was no statistically significant correlation between plasma thyroxin values and a given phase of the hyperthermic episode induced by the microinjections of 5--HT, PGE1 or bacteria. The possibility that an enhanced release of the thyroid hormone serves to sustain a long-term elevation in temperature evoked by a centrally acting pyrogenic substance is not supported.

Animals↗