Effects of insulin on hexose transport across blood-brain barrier in normoglycemia

The effects of insulin on 3-O-[14C]methylglucose transport across the blood-brain barrier (BBB) were studied in conscious rats under steady-state normoglycemic conditions. The [14C]methylglucose was infused intravenously at a constant rate, and animals were killed at various times between 5 and 30 min after the initiation of the infusion. The time course of the arterial plasma concentration of [14C]methylglucose was determined in timed arterial blood samples taken during the infusion. Local cerebral tissue concentrations of [14C]methylglucose at the time of killing were determined by quantitative autoradiography of brain sections. The rate constants for inward and outward transport of [14C]methylglucose across the BBB, K1, and k2, respectively, were estimated by a least-squares, best-fit of a kinetic equation to the measured time courses of plasma and tissue concentrations. K1 and k2 were reduced by an average of 24 and 31%, respectively, in gray matter and 7 and 16% in white matter from values estimated similarly in normal insulinemic control rats. The equilibrium distribution ratio, K1/k2, for [14C]methylglucose in brain increased by approximately 10-11% in the hyperinsulinemic animals. Because 3-O-[14C]methylglucose shares the same carrier that transports glucose and other hexoses across the BBB, these results suggest that hyperinsulinemia decreases the rate constants for transport but increases the distribution space for hexoses in brain. These effects are, however, quite small and are probably minor or negligible when compared with the major effects of insulin in other tissues.

Acute administration of high doses of estrogen increases glucose utilization throughout brain

The effects of high intravenous doses of estradiol benzoate on local cerebral glucose utilization were studied by the [14C]2-deoxyglucose method in conscious ovariectomized adult rats. Statistically significant increases in glucose utilization averaging 20% were observed in 42 of 60 anatomically discrete regions of the estrogen-treated animals. The possible role of catechol estrogen, a potent inhibitor of catechol-O-methyltransferase, in these effects is considered.

[Clinical results of synovectomy for rheumatoid wrist compared with the opposite side (author's transl)]

In the preoperative state, there were similar local findings on both sides of the wrist joint involved by rheumatoid arthritis in the roentgenogram. Synovectomy was performed on the one side of the wrist joint. Thirty six cases were compared with untreated controls and evaluated annually for eight years. From the roentgenological point of view, both wrists have almost similarly taken a turn for the worse. In spite of synovectomy, prevention of joint destruction has been unsuccessful. In the operated wrists it was due to ROM and pronation-supination which significantly improved wrist joint function. Although this improved level has been favorably maintained, there was a decline in dorsipalmar flexion and radio-ulnar flexion year after year. The results in the operated wrists were adequately better than the untreated wrists. Relief of pain was reported as follows: 94.4% : 2 years after the operation 84.8% : 4 years 81.3% : 6 years 80.0% : 8 years Synovectomy was followed by significantly less pain and satisfaction of treatment as reported by most patients. However analgetic effects of early synovectomy that was performed was ineffective and prevention of the destruction of joints roentgenologically met with negative results. The validity and the permanency of this synovectomy study was proved by the comparative evaluations made between the treated wrist joints and the untreated wrist joints, and also by the established clinical results.