Divergent Effects of Excess Dietary Vitamin A on Alimentary Cholesterolemia in Cockerels of Different Genetic Backgrounds

1975 ◽  
Vol 53 (2) ◽  
pp. 256-263
Author(s):  
Bill Woodward ◽  
B. E. March
Keyword(s):  
Vitamin A ◽  
Oral Dose ◽  
Single Oral Dose ◽  
New Hampshire ◽  
Dietary Cholesterol ◽  
The Other ◽  
Dietary Vitamin ◽  
White Leghorn ◽  
Variable Effect ◽  
Large Load

The variable effect of excessive vitamin A intake on alimentary cholesterolemia was investigated in cockerels of strains of White Leghorns and New Hampshires. With the New Hampshire cockerels, the feeding of 0.5% of dietary cholesterol resulted in greater cholesterolemia when the diet contained 1 700 I.U. of vitamin A per kilogram than when it contained 22 000 I.U. of vitamin A per kilogram. With the White Leghorn cockerels, on the other hand, cholesterolemia was enhanced with the higher level of dietary vitamin A. Absorption of a single oral dose of cholesterol was increased in birds of both breeds when vitamin A had been given previously by injection. In the White Leghorn cockerels the percentage of newly absorbed cholesterol in the hepatic pool was reduced by vitamin A administration, whereas in the New Hampshire cockerels the percentage was increased. It was concluded that excess vitamin A may have divergent effects on alimentary cholesterolemia in chickens of different genetic backgrounds as a result of opposite effects on the liver–blood ratio of a large load of cholesterol.

Effects of Vitamin A on Blood Coagulation and Clot-Lysis Times

1974 ◽  
Vol 52 (5) ◽  
pp. 984-990 ◽  
Author(s):  
Bill Woodward ◽  
B. E. March
Keyword(s):  
Vitamin A ◽  
Prothrombin Time ◽  
New Hampshire ◽  
Clot Lysis ◽  
White Leghorn ◽  
One Stage ◽  
Lysis Time ◽  
Euglobulin Lysis Time ◽  
K Deficiency ◽  
Single Comb

The effects of dietary excess of vitamin A on one-stage prothrombin time and on one-stage euglobulin-lysis time were studied in Single Comb White Leghorn, New Hampshire, and Black Australorp chicks. Prothrombin time was increased by the feeding of 100 000 and 200 000 I.U. of vitamin A per kilogram of diet to the Black Australorp chicks but it was not increased when these amounts of vitamin A were fed to either the White Leghorn or the New Hampshire chicks. The prolongation of prothrombin time was reversed within 16 h by injection of menadione. Vitamin A at 100 000 and 200 000 I.U./kg of diet decreased euglobulin-lysis times in chicks of all three breeds but increased the concentration of fibrinogen in the plasma. The effect of excess vitamin A on euglobulin-lysis time was not associated with induced vitamin K deficiency. The decreased euglobulin-lysis time resulting from intake of excess vitamin A persisted for 6 weeks subsequent to the feeding of moderate amounts of vitamin A.

scholarly journals Retinol and Retinyl Ester Responses in the Blood Plasma and Urine of Dogs after a Single Oral Dose of Vitamin A

2002 ◽  
Vol 132 (6) ◽  
pp. 1673S-1675S ◽  
Author(s):  
Jens Raila ◽  
Remo Radon ◽  
Annett Trüpschuch ◽  
Florian J. Schweigert
Keyword(s):  
Vitamin A ◽  
Oral Dose ◽  
Blood Plasma ◽  
Single Oral Dose ◽  
Retinyl Ester

Absorption and Conversion of a Single Oral Dose of beta-Carotene in Corn Oil to Vitamin A in Sprague-Dawley Rats with Low Reserve of Vitamin A

2003 ◽  
Vol 73 (4) ◽  
pp. 267-273 ◽  
Author(s):  
Barua
Keyword(s):  
Small Intestine ◽  
Vitamin A ◽  
Oral Dose ◽  
Single Oral Dose ◽  
Corn Oil ◽  
Absorbed Dose ◽  
Beta Carotene ◽  
Retinyl Palmitate ◽  
Sprague Dawley ◽  
Deficient Diet

This study was carried out to determine how much of a single oral dose of beta-carotene in oil is absorbed and how much of the absorbed dose is converted to retinoids in rats having a vitamin A reserve at the lowest end of adequate status. Weanling rats raised on a vitamin A-deficient diet for four weeks were given a single oral dose of either corn oil or beta-carotene dissolved in corn oil (1.86 mumol). Serum, liver, and the entire digestive tract of the rats were analyzed for carotenoids and retinoids. Results showed that 4 hours after dosing, 1.64 mumol (88%) of the dose of beta-carotene was found intact, with 17.6% found in the stomach, 21% in the small intestine, and 49.3% in the large intestine. A total of 0.28 mumol of newly formed retinoids (expressed as retinyl palmitate) was present in serum, liver, and mucosa of small intestine. The results suggest that a single oral dose of beta-carotene might not be an effective way of raising vitamin A status in rats.

Changes in the binding of oestradiol to uterine oestrogen receptors induced by some progesterone and 19-nor-testosterone derivatives

1983 ◽  
Vol 98 (3) ◽  
pp. 385-389 ◽  
Author(s):  
Francesco Di Carlo ◽  
Elena Gallo ◽  
Giuseppe Conti ◽  
Silvia Racca
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Medroxyprogesterone Acetate ◽  
The Other ◽  
Receptor Interaction ◽  
Oestrogen Receptors ◽  
Rat Uterus ◽  
The Hours

The effects of two progesterone derivatives, namely medroxyprogesterone acetate (MPA) and chlormadinone, and two 19-nor-testosterone derivatives, namely norgestrel and norethisterone, on the binding of oestradiol to its cytoplasmic receptors in the rat uterus were compared. In experiments performed in vivo, the rats were given a single oral dose (15 mg/kg) of one of the four progestins and killed 1, 6, 24 and 48 h later. Norgestrel, norethisterone and MPA induced a prompt and remarkable decrease in oestradiol–receptor interaction 1 h after treatment. This reduction lasted almost unchanged for 24 h in rats treated with MPA or norgestrel, but was much lower in animals given norethisterone. In the hours that followed, the effect of MPA and norgestrel began to decrease, but was still detectable after 48 h, whereas the effect of norethisterone had disappeared by this time. The effect of chlormadinone was much less than that induced by both MPA and norgestrel 1, 6 and 24 h after treatment. On the other hand, this effect was less than that caused by norethisterone 1 h after administration, equal after 6 h and much greater after 24 and 48 h. In experiments performed in vitro, the different ability of the four progestins to interfere with the capacity of oestradiol to bind to its receptors was confirmed. In conclusion, all the synthetic progestins used were able to reduce the binding of oestradiol to its cytoplasmic receptors, although there was a clear difference between the progestins in the intensity and duration of this effect. This could be one of the mechanisms by which progestins modulate the activity of oestrogens in target tissues.

Sign in / Sign up

Export Citation Format

Share Document