Search PubMed⌕ Search

Biomedical subjects

J M Stolk

Publications and source records attributed to J M Stolk.

At least 37 records · Page 2Linked to original sources
PubMed1980

The inverse relationship between serum dopamine-beta-hydroxylase activity and thyroid function.

Serum dopamine-beta-hydroxylase (DBH) activity is inversely related to thyroid status in both humans and rats. The low level of serum DBH activity in hyperthyroid rats is accompanied by a rapid rate of disappearance of enzyme activity after the injection of exogenous bovine DBH. Conversely, the high level of serum DBH activity in hypothyroid rats is accompanied by a slow rate of exogenous DBH disappearance. These results suggest that the extraneuronal disposal pathway for DBH is an important factor in the regulation of the level of DBH activity in altered thyroid function in both humans and rats.

Adrenal Medulla↗
PubMed1978

Depression, hypertension, and serum dopamine-beta-hydroxylase activity.

Serum dopamine-beta-hydroxylase (DBH) activity was measured in a heterogeneous sample of 290 outpatients awaiting medical, surgical, or psychiatric appointments at a Veterans Administration Hospital. All patients were assessed for depressive symptomatology by the Zung Self-Rating Depression Scale (SDS) and for elevated diastolic blood pressure (BP greater than or equal to 90 mm Hg). Elevated DBH activity was associated with SDS scores greater than or equal to 60. No statistical association was found between DBH activity and diastolic BP. Two pharmacological agents, alpha-methyl-DOPA and minor tranquilizers, also were associated with significant alterations in serum DBH activity.

Adult↗
PubMed1978

Serum dopamine-beta-hydroxylase activity does not reflect sympathetic activation during hypoglycemia.

The relationship between serum dopamine-beta-hydroxylase (DBH) activity and sympathetic nervous system activation in response to insulin-induced hypoglycemia was investigated in healthy young male and female volunteers. Serum DBH activity and glucose levels were measured in blood samples obtained 30 min before and 90 min after the iv administration of regular insulin or placebo. All subjects developed significant hypoglycemia in response to the insulin and manifested signs of sympathetic activation, including increased heart rate, diaphoresis, and lightheadedness. However, despite obvious clinical manifestations of increased sympathetic activity, none of the subjects exhibited a significant alteration in serum DBH activity either in comparison to baseline or placebo values. These data question the suitability of serum DBH measurements for assessing adrenomedullary function in man.

Dopamine beta-Hydroxylase↗
PubMed1977

Axoplasmic transport of norepinephrine in the locus coeruleus-hypothalamic system in the rat.

The axoplasmic transport of norepinephrine (NE) between the nucleus locus coeruleus (LC) and the hypothalamus has been measured by three methods which employ the stereotaxic injection of [3H]catecholamines in the rat brain. [3H]NE is synthesized from [3H]dopamine (DA) injected into the LC and transported at a rate of 0.8-0.9 mm/h. This rate is probably an underestimate since it includes the time required for uptake and conversion of [3H]DA to [3H]NE prior to transport. Measurement of transport of [3H]NE between the posterior and anterior hypothalamus gives a rate of 2 mm/h which is independent of [3H]DA uptake and [3H]NE synthesis. This rate is in good agreement with the 1.9 mm/h figure calculated for [3H]NE transport in the system after LC injection of [3H]NE and represents a closer estimate of the true rate of axoplasmic transport than the 0.8-0.9 mm/h estimate. Transport of [3H]NE occurs through primarily ipsilateral NE fibers running in the median forebrain bundle and is blocked by 6-hydroxydopamine lesions in the bundle. Early appearing [3H]NE in the hypothalamus forms a relatively stable pool which is unaffected by median forebrain bundle lesions and is essentially unchanged by [3H]NE transported from the LC. This pool appears to be derived from non-specific spread of [3H]DA after injection, probably through the cerebrospinal fluid.

Afferent Pathways↗