Biomedical subjects

M Perz

Publications and source records attributed to M Perz.

10 recordsLinked to original sources

PubMed2002

Effect of hypothermia on insulin-receptor interaction in different rat tissues.

Experimental hypothermia caused extensive changes in the number of both classes of insulin receptors in different rat tissues. In the liver, the number of high affinity insulin receptors (HAIRs) decreased by 50% (from 25.3 to 12.6 fmol/mg membrane protein), whereas number of low affinity insulin receptors (LAIRs) was almost unchanged in comparison to normothermic animals (5.63 and 4.39 pmol/mg, respectively). In the adipose tissue, number of both classes was reduced--HAIRs by 81% (from 24.0 to 4.50 fmol/mg) and LAIRs by 92% (from 16.0 to 1.29 pmol/mg). In the skeletal muscle, capacity of HAIRs was not changed (16.2 and 19.3 fmol/mg in normo- and hypothermic animals, respectively), whereas number of LAIRs increased by 150% (from 6.65 to 16.6 pmol/mg). Hypothermic rats also showed lower amount (by 85%) of LAIRs in the heart muscle (9.37 and 1.43 pmol/mg in control and experimental animals, respectively). Simultaneously, no significant changes were found in HAIRs (16.3 and 11.9 fmol/mg, respectively) and LAIRs (4.43 and 3.88 pmol/mg, respectively) in the brain. These differences in insulin receptors responses to hypothermia may reflect different physiological role of insulin in the regulation of target cell metabolism and/or the differences in tissue distribution of the insulin receptor isoforms.

Adipose Tissue↗

PubMed2000

Age dependent changes of insulin receptors in rat tissues.

Aging is associated with insulin resistance but the exact molecular mechanism is still unknown. Tissue insulin resistance can be evoked by the decreased sensitivity to insulin, the decreased responsiveness to hormone or both. As the first step in insulin action is its binding to alfa subunits of the receptor we, therefore, studied the insulin binding kinetics in plasma membranes of the liver, heart and skeletal muscle in order to establish whether their ability to bind the hormone is altered with aging. Plasma membranes were prepared and purified according to Havrankowa and binding assay was performed using (125I)-iodoinsulin. The kinetic parameters of the hormone-receptor interaction were analysed by the method of Scatchard using the LIGAND-Pc v.3.1. computer program. The binding potency of insulin was calculated as IC50 using ALLFIT-Pc v.2.7. computer program. We have shown that there are striking differences in insulin binding kinetics in newborn and old rats, depending on kind of tissue tested. The liver plasma membranes ability for insulin binding, number of high (HAIR) and low (LAIR) affinity insulin receptors, values of the dissociation constants and products of association constants and number of insulin receptors, were almost the same, being not dependent on age of the rats. By contrast, there is less high affinity insulin receptors in skeletal muscle of the old animals. The most dramatic changes in insulin binding occur in the heart where both high and low affinity insulin receptors are greatly affected by aging. Our results indicate that the response of the three tissues tested to hyperglycemia and hyperinsulinemia, observed in the old rats, has not been identical and probably can be accounted for by the different distribution of insulin receptor isoforms in the liver, heart and skeletal muscles as shown recently by Vidal et al.

Aging↗

PubMed1998

Characteristics of insulin receptor binding to various rat tissues.

The first step in insulin action is its specific binding to alpha-subunits of the receptor in the plasma membrane. Rats of Wistar strain are commonly used as laboratory animals but there are no data comparing insulin binding by various rat tissues. We studied the insulin binding kinetics in plasma membranes isolated from hearts, livers, brains, skeletal muscles, adipose tissue, thymus and testes in order to compare their ability to bind 125I-insulin and to test which membrane preparation is most useful and convenient for such a study. The dissociation constant (Kd) and the quantity of receptors measured as a binding capacity were determined by the Scatchard method using the LIGAND computer program whereas the binding potency of insulin was calculated as IC50 using the ALLFIT computer program. We also introduced the product of Ka x R50 (affinity constant multiplied by binding capacity) as an index which describes the functional features of insulin receptors taking into account both number of insulin receptors and their affinity. Taking all the parameters of insulin binding tested together we can conclude that the liver and, to some extent, adipose tissue may provide a useful model for studying hormone-receptor interaction. By contrast, to the group of rat tissues responding rather poorly to insulin belong thymus and testis.

Adipose Tissue↗

PubMed1996

Multicultural maternal and child health outreach: Washington State strategies to assure access for Asian and Pacific Islander women and children.

This article outlines some of the barriers to health care experienced by Asian and Pacific Islander Communities. The authors then describe a number of strategies the Washington State Department of Health has used to reduce cultural and linguistic barriers to health care. As a state health agency, the Department has promoted accessible programs through mechanisms such as improved data collection, culturally competent staff, targeted outreach, and development of partnerships with community organizations and other agencies to promote culturally accessible health care delivery.

Adolescent↗

PubMed1966