The interactive effect of dietary water-soluble vitamin levels on the depression of gonadal development in growing male rats kept under disturbed daily rhythm.

The purpose of this study was to clarify the effects of nutrients on the gonadal development of male rats kept under constant darkness as a model of disturbed daily rhythm. In the present study we examined the effects of nine water-soluble vitamins. We selected 7 water-soluble vitamins (choline, nicotinic acid (NA), pantothenic acid (PA), vitamin B6 (VB6), vitamin B1 (VB1), vitamin B2 (VB2) and folic acid (FA)) as experimental factors for the first experiment (Ex. 1) and biotin and vitamin B12 (VB12) as experimental factors for the second experiment (Ex. 2). The dietary content of these vitamins was normal or six times the normal content. Lighting condition (L.C.) was also added as a factor. Four-week-old male rats (Fischer 344 strain) were kept under constant darkness or normal lighting (12-h light/dark cycle) for 4 wk. The depression of gonadal development in the constant darkness groups (D-groups) was shown. The L.C., PA, VB6 and VB1 influenced testes development, and these three vitamins had interactions with L.C. Among the normal lighting groups (N-groups), the highest value for testes weight was observed under the normal-PA, high-VB6 and high-B1 diet; on the other hand, among the D-groups, it was observed under the high-PA, normal-VB6 and normal-VB1 diet. The results showed that the depression of gonadal development in rats kept under disturbed daily rhythm was improved by getting a high amount of PA and normal amount of VB6 and VB1.