9-cis retinoic acid stereoisomer binds and activates the nuclear receptor RXR alpha.

Vitamin A (retinol) and its natural derivatives are required for many physiological processes. The activity of retinoids is thought to be mediated by interactions with two subfamilies of nuclear retinoic acid receptors, RAR and RXR. The RARs bind all-trans retinoic acid (t-RA) with high affinity and alter gene expression as a consequence of this direct ligand interaction.

Time course of testicular degeneration in rats induced by a synthetic retinoid (Ro 23-2895) and evidence for induction of hypovitaminosis A in the testes.

Eight-week-old male Sprague--Dawley rats were dosed by gavage with 90 mg/kg of Ro 23-2895, (all-E)-9-[2-(nonyloxy)phenyl]-2,4,6,8 nonatetraenoic acid, dissolved in Tween 80. Treated animals (n = 3--4) were sacrificed after 3, 7, 11 and 21 days of dosing. Control rats (n = 3) received an equal volume of Tween 80 and were sacrificed after 3 or 21 days.

The reversibility of nitrobenzene-induced testicular toxicity: continuous monitoring of sperm output from vasocystotomized rats.

Exposure of rats to nitrobenzene produces a degeneration of the seminiferous epithelium of the testes. Sperm production was continuously monitored in rats surgically prepared by anastomosing the vas deferentia with the urinary bladder to evaluate the reversibility of nitrobenzene toxicity. Rates of sperm production were monitored by collecting urine and counting sperm microscopically with a hemocytometer.

Studies on the testicular effects of vitamin A palmitate in the Sprague-Dawley rat.

The purpose of the research was to investigate the mechanism of reported vitamin A-induced testicular degeneration. Three studies of vitamin A toxicity were conducted in male Sprague-Dawley rats; a 10-day study with daily ip injections of retinol palmitate at doses of 0, 115,000 and 230,000 IU/kg/day in adult rats; a 10-day study with juvenile rats treated with 115,000 IU/kg/day, pair-fed controls and ad lib.-fed controls; a 13-wk dietary study in which retinol palmitate beadlets were mixed in the food of juvenile rats at doses of 0, 60,000, 120,000 and 200,000 IU/kg/day; a second untreated group was pair-fed to the high-dose group.