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Patients with cystathionine (cy) synthase deficiency are unable to synthesize cy from homocysteine and serine. Wong et al. showed that they could form cy from homoserine and cyst(e)ine, and thus might correct cy deficiency. The effect of diets containing Jack Bean (JB) (with 2% homoserine) on Spraque-Dawley rats from weaning was tested in groups of 30 each as follows: A, Purina Chow, B, 44.5% corn + soya (so), C, 44.5% JB + so, D, 44.5% heated JB + so, E, 30% heated JB + so, F, 65.8% + so, G, 88.7% JB. All diets contained salts, vitamin, 1.3% cystine and 5% corn oil. G showed inanition but there was no significant difference in the mortality of other groups. From 101 to 111 days, all rats were tested by a novel computer-controlled behavioral system which required them to lever-press for standardized food pellets. Statistical analysis showed that C and F pressed for significantly more pellets that A. C, D and E pressed for significantly more pellets than B. 26% A, 70% C and 30% F “learned” to lever-press within 30 min (A vs C, p<0.001). C could “recall” significantly faster than B, Heating of JB (to destroy urease) did not produce any significant difference. This demonstrated a rapid, quantitative and reliable technique in evaluating “learning”, “recall” and “motivation” in toxicologic or behavioral studies, and revealed the superior performance in some groups of rats fed JB containing diets.

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Ts'o, T., Wong, P. A BEHAVIORAL STUDY IN RATS TREATED WITH AN EXPERIMENTAL DIET FOR HOMOCYSTINURIA. Pediatr Res 8, 396 (1974) doi:10.1203/00006450-197404000-00338

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