Secretion into the uterine lumen follows a precise pattern during early pregnancy. Near the end of the second week of pregnancy and coincident with elongation of conceptuses, retinol, retinol binding protein (RBP), estradiol (E2), and prostaglandins E (PGE) and F (PGF) increase in the uterine lumen, and RBP mRNA increases in the endometrium. In the present studies the potential for E2 (0.1 micr...

BACKGROUND Maternal vitamin A and iron status was investigated among lactating mothers in a rural community in Kenya. The aim of the study was to establish the prevalence and the relationship of these key nutrients to maternal body composition. METHODS Eighty-eight mothers provided samples of breast milk and blood for determination of breast milk vitamin A, serum retinol and ferritin. Estimat...

Methods: Alpha tocopherol, gamma tocopherol, and retinol are assayed using fluorescence detection. Excitation/emission wavelengths are 295 nm/330 nm and 325 nm/470 nm for the analysis of both tocopherols and retinol, respectively. Retinol acetate is employed as the internal standard. The reversed phase method incorporates gradient elution with a mobile phase consisting of methanol and acetonitr...

Retinol (vitamin A) in concentrations above (5 microgram/ml inhibits the stimulation of human lymphocytes by phytohemagglutinin and phorbol myristate acetate. This is in contrast to bovine lymphocytes in which retinol inhibits only phorbol myristate acetate stimulation of lymphocytes. The cause of the inhibition does not appear to be due to a direct toxic action because the viability and ultras...

The reactivity of retinol with peroxynitrite, which is a strong oxidant and has been reported to induce several biological damages, was investigated. 13-cis-14-nitroretinol (1), 13-trans-14-nitroretinol (2), 13-apo-beta-carotenone (3), retinal (4), 11,14-epoxyretinol (5), and 11,15-epoxyretinol (6) were identified as reaction products of retinol with peroxynitrite. From these results, it was ob...

Retinol and vitamin A derivatives influence cell differentiation, proliferation, and apoptosis and play an important physiologic role in a wide range of biological processes. Retinol is obtained from foods of animal origin. Retinol derivatives are fundamental for vision, while retinoic acid is essential for skin and bone growth. Intracellular retinoid bioavailability is regulated by the presenc...

Retinol, the alcohol form of vitamin A is a key dietary component that plays a critical role in vertebrate development, cell differentiation, reproduction, vision and immune system. Natural and synthetic analogs of retinol, called retinoids, have generally been associated with the cell differentiation via retinoic acid which is the most potent metabolite of retinol. However, a direct function o...

In photoreceptor cells of the retina, photoisomerization of 11-cis-retinal to all-trans-retinal triggers phototransduction. Regeneration of 11-cis-retinal proceeds via a complex set of reactions in photoreceptors and in adjacent retinal pigment epithelial cells where all-trans-retinol is isomerized to 11-cis-retinol. Our results show that isomerization in vitro only occurs in the presence of ap...

Interphotoreceptor retinol-binding protein (IRBP) is a large retinol-carrying glycoprotein, located only in the interphotoreceptor (or subretinal) space of vertebrate eyes. It has recently been purified to apparent homogeneity. The present report presents its sedimentation, spectroscopic, and binding properties. The molecular weight of bovine IRBP, determined by sedimentation equilibrium, is 13...

This study was conducted to examine the possible association between vitamin A status and overnutrition in Chinese urban children and adolescents. Weight, height and serum retinol were assessed in total 3457 children (7-9.9 years of age) and adolescents (10-17 years of age), using urban region data from the China National Nutrition and Health Survey 2010-2013 (CHNNS2010-2013) which is a nationa...