Signaling Pathways in Insulin- and IGF-I Mediated Oocyte Maturation in Lower Vertebrates.

The endocrine control of oocyte maturation in fish and amphibians has proved to be a valuable model for investigating the rapid and non-genomic steroid actions at the cell surface. Considerable progress has made over the last decade in elucidating signaling pathways in steroid-induced oocyte maturation. In addition to steroids, various growth factors have also been reported to be involved in this process and progress being made to elucidate their mechanism of actions. Exposure of fully-grown oocytes to steroids or growth factors (insulin/IGFs) initiates various signaling cascade, leading to formation and activation of maturation-promoting factor (MPF), a key enzyme that catalyzes entry into M-phase of meiosis I and II. Whereas the function of MPF in promoting oocyte maturation is ubiquitous, there are differences in signaling pathways between steroids- and growth factors-induced oocyte maturation in amphibian and fish. Here, we have reviewed the recent advances on the signaling pathways in insulin- and IGF-I-induced oocyte maturation in these two groups of non-mammalian vertebrates. New findings demonstrating the involvement of PI3 kinase and MAP kinase in induction of oocyte maturation by insulin and IGF-I are presented.

Lipid profile of Indian children and adolescents.

Dyslipidaemia when diagnosed in childhood predicts the development of clinical atherosclerotic disease in adulthood. Ever since we became aware of the abnormally high incidence of coronary artery disease amongst Indians, there always has been an ever-growing need for study of lipid values amongst Indian children and adolescents. Five hundred and eighty-six children (352 boys and 234 girls) from a public school aged between 8 and 18 years (mean age: 12.86 for boys and 12.15 for girls) were included in the study for assessment of lipid profile during the period from April, 1999 to March, 2000. Fasting venous blood was drawn from each child and total cholesterol and triglyceride levels were measured by enzymatic method, high-density lipoportein (HDL)-cholesterol was measured using specific precipitation method and lipoprotein (a) [Lp (a)] was measured by immunoturbidimetric method. After biochemical estimation was completed reference values and percentiles were calculated for each lipid component. Mean cholesterol and triglyceride values were higher amongst girls compared to boys. HDL-cholesterol values were lower amongst Indian boys compared to girls. Mean Lp (a) values were higher amongst both Indian boys and girls and more so amongst girls compared to boys. Since Lp(a) values remain unchanged through ages, these values should represent corresponding values in adult Indian males and females. It is being expected that data presented in this study should form guidelines with regard to dietary and pharmacological intervention for dyslipidaemia amongst children and adolescents.