PLATES XXIX-XXXIII) THE lesions of experimental lathyrism are striking, but it is not known how they are produced. There is evidence that a ground-substance change may be responsible (Menzies and Mills, 1957 ; Ham, 1960) and other observations have suggested an alteration in collagen (Hurley and Ham, 1959 ; Levene and Gross, 1959). In the present work, the specificity of labelling of sulphated mucopolysaccharides in vivo with sulphur-36 given as sulphate (Curran and Kennedy, 1955) has made it possible to determine the distribution of these sulphated compounds by autoradiography, and their relation to lathyric lesions. In a similar way protein metabolism in the lesions has been investigated with sulphur-35 methionine and carbon-14 glycine as precursors. The effect of lathyrogenic agents on the distribution of 36S-sulphate-labelled compounds in healing fractures has also been investigated. The results sustain the hypothesis that the essential change in lathyrism is a failure of formation of chondroitin sulphate A and C complexes with protein, and a subsequent defect in fibrogenesis.
MATERIALS AND METHODSA sweet-pea diet, p-amino-propionitrile (BA.E") and amino-acetonitrile ( M ) were used to produce experimental lathyriem in 52 Wistar rats. The animals were 4-7 weeks old a t the beginning of the experiment. Both sexes were used. Cyrrtamine, reported as lathyrogenic (Dasler and Milliser, 1958). was given to 12 weanling rats. Animals suffering from lathyrism are here called lathyric animals.Swest pea (Geiger st al., 1933 ; Ponseti and Baird, 1952). The diet consisted of Lathyma odoratua peas and pellets of standard rat diet crushed together in equal parts by weight. It was given to 11 rats for 3 mth to 1 yr. One of the animals waa given daily subcutaneous injections of BAPN (Wawzonek et al., 1955) so that it received a total of 30 mg. over 15 days, and another received 80 mg. given similarly over 20 days, before injection of isotope.A A N (Wawzonek et al., 1955). This compound waa given daily in 1 6 2 0 mg. doses in water, orally or subcutaneously, to 41 rats. T h e total dose per animal ranged from 60 to 550 mg. Five of these animals received daily 1 mg. deoxycorticosterone acetate (DOCA) subcutaneously (Selye and Bois, 1957). The total dose of DOCA per animal ranged from 15 to 55 mg. and the corresponding AAN range was 250-550 mg. Cyata?nine (Daaler and Milliser, 1958). Cystamine dihydrochloride waa given daily in 10-40 mg. doses in water orally to 12 rats. The total dose per animal ranged from 240 to 1050 mg.