Derrel W. Clarke

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Twelve of 129 black patients with youth-onset diabetes were identified as having an unusual clinical course, with apparent insulin dependence at the time of presentation followed by absence of dependence months to years later. This atypical form of diabetes was found in at least two generations in 9 of the 12 families of the propositi. Fourteen of the(More)
Depolarization of neuronal cells in primary culture from the rat brain by potassium ions in the presence of calcium or by veratridine caused a greater than three-fold stimulation of release of immunoreactive insulin. HPLC of the released insulin immunoreactivity from the neuronal cultures comigrated with the two rat insulins. The depolarization-induced(More)
The kinetics of 125I-insulin binding and physiological activity of insulin on glial cells cultured from brains of 1-day-old rats have been studied. Binding of 125I-insulin to cultured glial cells was specific, reversible, and time-dependent. Porcine and chicken insulin competed equally for 125I-insulin binding while other hormones or insulin analogs(More)
We studied the structural and functional characteristics of insulin receptors from rat brain and liver from late gestation through adulthood as well as from cultured neuronal and glial cells from neonatal rats. Specific insulin binding was present on membrane preparations from brain and liver at all stages of development studied, with maximal binding in(More)
Neuronal cells from 1-day-old rat brain in primary culture have been utilized in the present study to characterize insulin-binding sites and a possible action of insulin on these cells. Binding of 125I-insulin to neuronal cultures was 90% specific and time-dependent and reached equilibrium in 120 min. Specific binding was reversible with greater than 90% of(More)
The effect of insulin on macromolecular synthesis in glial cells cultured from brains of 1-day-old rats was studied to investigate the role of insulin in brain growth. Insulin caused a dose-dependent stimulation of protein synthesis (measured by [3H]valine incorporation into protein) that became significant by 7 nM insulin. Maximal stimulation of protein(More)
The present study was conducted to characterize insulin receptors and insulin action in rat brain cells. Binding of [125I]insulin to cells obtained by mechanically dissociating rat brains was 86% specific, time-dependent and reached equilibrium within 90 min. The t1/2 of association was 14 min and t1/2 of dissociation was 8 min. Scatchard analysis(More)
Neuronal cells in primary culture have been demonstrated to possess specific insulin receptors (Boyd et al., J. Biol. Chem., 260 (1985) 15880-15884). Incubation of these cultures with insulin causes a dose-dependent inhibition of maprotiline-sensitive [3H]norepinephrine uptake. Maximum inhibition of 95% of maprotiline-sensitive norepinephrine uptake was(More)
The present study was conducted to characterize insulin receptors and to determine the effects of insulin in synaptosomes prepared from adult rat brains. Binding of125I-insulin to synaptosome insulin receptors was highly specific and time dependent: equilibrium binding was obtained within 60 minutes, and a t1/2 of dissociation of 26 minutes. Cross-linking(More)