Vitamin A and reproduction in rats
Tóm tắt
Retinoic acid (vitamin A acid), the carboxylic acid corresponding to the primary alcohol retinol (vitamin A), has previously been thought to fulfil all the functions of vitamin A except in vision, since rats fed a diet deficient in retinol but supplemented with retinoic acid grow well, outwardly appearing healthy, yet become blind. This paper reports that female rats on such a diet had normal oestrous cycles and became pregnant when mated, but always resorbed the foetuses and no litters were born. The first abnormalities detected were necrosis and slight polymorph infiltration around the periphery of the placental disk about the sixteenth day of pregnancy. Supplementation with retinol as late as the tenth day resulted in the birth of a healthy litter. Retinoic acid therefore maintained the early but not the later stages of gestation. When very small amounts of retinol were given during pregnancy, dead or weak young were born; on higher supplements of the vitamin, litters were weaned successfully. By this means young rats were produced with negligible stores of retinol. Male rats fed retinoic acid but not retinol had small and often oedematous testes. The germinal epithelium sloughed off and in some tubules the lumen was obliterated, but in others the lumen remained, and in these some spermatocytes and spermatogonia were held tenaciously. The seminal vesicles were smaller than in controls given retinol. In rats born with negligible stores of retinol—see above—and maintained on retinoic acid, the testes remained infantile; spermatids were never formed. Feeding retinol restored spermatogenesis in degenerate testes and promoted the normal development of testes that had remained infantile; it also ensured the growth of the seminal vesicles. Retinoic acid did not therefore serve in reproduction, although it replaced the true vitamin in maintaining life, growth and general health. Besides the latter so-called systemic function, vitamin A must have a discrete and specific role in reproduction, viz. that performed by retinol but not by retinoic acid. From among the many previously reported features of disordered reproduction in vitamin A-deficient animals, it was possible to distinguish which had arisen from a failure of this specifically ‘reproductive’ role and which from a ‘systemic’ deficiency. The inactivity of retinoic acid in reproduction demonstrates that in rats vitamin A has not two, as previously thought, but three dissociable modes of action: (1) systemic; (2) in vision; and (3) in reproduction.
Từ khóa
Tài liệu tham khảo
Boguth W. Horn V. Soliman M. K. & Weiser H. i960 Int. Vitaminsforsch. 31 6.
Browman L. G. 1939 Amer.
Cannon M. D., 1940, Proc, J. Physiol., 125, 335
Soc.Exp. Biol. N.Y. 44 129.
Dowling J. E., 1961, Amer, J. Clin. Nutr., 9
Evans H. M., 1932, Amer, J. Physiol., 99, 477
Evans H. M., 1922, Anat. Bee., 23, 17
Harris P. L. 1953 In Symposium on nutrition p. 70. (Ed. Herriott R. M.). Baltimore: Johns Hopkins Press.
Harris P. L. i960 Vitam. & Norm. 18 341.
Howell J. McC. Thompson J. N. & Pitt G. A. J. 19636 J. Beprod. Fertil. (In press.)
International Union of Pure and Applied Chemistry: Commission on the Nomenclature of Biological Chemistry i960 J. Amer. Chem. Soc. 82 5581.
Kaiter H., 1959, Physiol, Bev., 39, 69
Lawless J. J., 1936, Anat. Bee., 66, 455
Light R. F. Alscher R. P. & Frey C. N. 1944 Science 100 225. Maddock C. L. Cohen J. & Wolbach S. B. 1953 Arch. Path. 56 333. Mahadevan S. Murthy S. K. & Ganguly J. 1962 Biochem. Mason K. E. 1933 Amer. J. Anat. 52 153. Mason K. E. 1935 Amer. J. Anat. 57 303. 85 326.
Mason K. E. 1939 In Williams and Wilkins. Sex and internal secretions 2nd ed. p. 1149. (Ed. Allen E.). Baltimore:
Milas N. A. 1954 In The vitamins vol. 1 p. 4. (Eds. Sebrell W. M. and Harris R. S.). New York: Academic Press.
Mitzkewitseh M. S., 1934, Arch. exp, Path. Pharmak., 174, 339
Moore T. 1953 In Symposium on nutrition p. 28. (Ed. Herriott R. M.). Baltimore: Johns Hopkins Press.
Moore T. 1957 Vitamin A. Amsterdam: Elsevier.
Nelson E. C., 1962, Fed, Proc., 21, 474
Redfeam E. R. i960 Arch. Biochem. Biophys. 91 226.
Robeson C. D., 1952, U.S, Patent, 2, 583
Rokkones T., 1956, Int, Z. Vitaminforsch., 26, 1
Sharman I. M., 1949, Brit, J. Nutr., 3, viii
Sure B., 1928, J. Agric. Res., 37, 87
Thompson J. N. Howell J. McC. & Pitt G. A. J. 1961a Biochem. J. 80 16p.
Thompson J. N. Howell J. McC. & Pitt G. A. J. 19616 Biochem. J. 80 25p.
Van Os P. M., 1936, Acta brev. neerl, Physiol., 6, 151
Wald G. & Hubbard R. i960 In The enzymes 2nd ed. vol 3 p. 369. (Eds. Boyer P. D. Lardy H. &Myrback K.). New York: Academic Press.
Warkany J., 1954, J. Cell. Comp. Physiol. 43 (suppl.), p. 207.
Weber F. Gloor U. & Wiss O. i960 Helv. physiol. Acta 18 C 97.
Wolf G., 1963, Biochim. biophys, Acta, 69, 524
Wood J. D., 1962, Canad, J. Biochem. Physiol., 40, 529