An unusual neuropsychiatric disorder inherited in autosomal dominant fashion occurred in three successive generations of a family. Symptoms commenced late in the fifth decade in six affected patients and led to death in four to six years. The earliest and most prominent symptom was mental depression not responsive to antidepressant drugs or electroconvulsive therapy. This was accompanied by exhaustion, sleep disturbances, and marked weight loss. Later in the disease, symptoms of parkinsonism appeared, and respiratory failure occured terminally. The most recently affected family member was investigated biochemically late in his illness. Concentrations of taurine were greatly diminished in plasma and cerebrospinal fluid, and at autopsy, all regions of brain examined had a markedly reduced taurine content. Since taurine is a putative inhibitory synaptic transmitter, deficiency of brain taurine may possibly have caused the psychiatric and neurological manifestations of this disorder.
Free amino compounds were measured in 16 rapidly frozen epileptogenic foci excised from temporal or frontal cortex of nine patients with focal epilepsy, and in single cortical biopsy specimens obtained from 16 nonepileptic patients. Unlike the findings of a previous study, glutamic and aspartic acids were not diminished in the foci, nor was there a decrease in gamma-aminobutyric acid (GABA) or taurine levels. Glycine content was markedly elevated in two of 16 epileptogenic foci. These results do not suggest that deficiencies of GABA or of taurine, amino acids that may act physiologically as inhibitory neurotransmitters or modulators of inhibition, are causes of focal epilepsy, nor do they provide a logical basis for clinical trials of taurine in treatment of human epilepsy.
—GABA contents are significantly decreased in the caudate nucleus, putamen‐globus pallidus, substantia nigra, and occipital cortex in autopsied brain from Huntington's chorea patients, as compared to values in the same regions from control subjects who have died without neurological disease. Homocarnosine levels are lower in choreic than in control brain, but only in the putamen‐globus pallidus and the cerebellar cortex are the differences significant. Activity of the enzyme which synthesizes GABA, glutamic acid decarboxylase, is reduced in the brains of some choreic patients, but may be equally low in brain of control subjects, even though the latter exhibit normal brain GABA content. Low glutamic acid decarboxylase activity in autopsied human brain is not uniquely characteristic of Huntington's chorea. No evidence was found in this study for an inhibitor of glutamic acid decarboxylase in choreic brain, nor for the presence of an isoenzyme with decreased affinity for glutamate. GABA aminotransferase, the enzyme which degrades GABA, was equally active in control and choreic brain; therefore, increased activity of this enzyme cannot account for the low brain GABA levels in Huntington's chorea.
The present studies examine the effects of testosterone (T) and LHRH, alone or in combination, on the amount of FSH secreted by pituitary cells in culture. FSH was quantified by RIA and radioreceptor assay (RRA). Half of the cultures were exposed to T for 3 days. The remainder served as controls. Each of these two groups was divided in half and exposed to medium only or LHRH (10(-8) M) for 4 h. Medium was collected from all cultures after 3 days +/- T (medium 1) and after 4 h +/- LHRH (medium 2). After medium 2 collection, cell homogenates were prepared. In a second study, T-treated cell cultures also received 0, 0.5, or 5.0 micrograms/dish tunicamycin for the last 16 h of the 3-day incubation. During the 3 days of culture, the T-treated group secreted greater amounts of immunoactive FSH than controls. However, LHRH-induced FSH release measured by RIA was blunted as a result of T exposure compared with untreated controls. T treatment elevated intracellular immuno-FSH stores. Each sample was quantitated for FSH activity by RRA, and the FSH RRA/RIA was calculated. T and/or LHRH treatment, while eliciting FSH hypersecretion, caused a reduction in the RRA/RIA of secreted FSH. Changes in the RRA/RIA are thought to occur as a result of alterations in the glycosylation of FSH. To test this hypothesis, T-treated cells were exposed to tunicamycin, a drug that reduces the rate of glycosylation of secreted proteins. Exposure of cells to this drug prevented the reduction in the RRA/RIA of secreted FSH caused by T and/or LHRH. FSH secreted from control, T-treated, or T-treated plus tunicamycin-exposed cells was examined by isoelectric focusing. T-Treated cells released a greater proportion of FSH forms with lower isoelectric points (indicative of a greater degree of glycosylation) compared with controls. Tunicamycin exposure reversed T's effect upon the isoelectric profile. These studies demonstrate a direct pituitary action of LHRH and T upon the type of FSH released. During times of hormonally induced increases in the rate of FSH secretion, the pituitary releases FSH forms that are more heavily glycosylated, exhibit a lower isoelectric point, and show a reduced RRA/RIA. FSH secreted after T treatment would be expected to have an increased plasma half-life due to the protective effects of the sugar residues. Thus, the existing hormonal milieu exerts a multidimensional effect upon FSH released by pituitary cells in culture that cannot be appreciated by RIA assessment alone.
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