The Effects of Nutrients in Improving the Depression of Gonadal Development in Growing Male Rats Kept under Disturbed Daily Rhythm -Investigations Based on the L8(27) Type Orthogonal Array-

Abstract

SummaryThe purpose of this experiment 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. Protein, methionine, vitamins, minerals and fat were selected as experimental factors, and eight kinds of diets were prepared based on the L8(27) type orthogonal array. Dietary contents of the nutrients were normal (AIN-76 diet) or 1/3 to 1/2 of the normal content. Four-week-old rats (Fischer 344 strain) were kept under constant darkness for 4 wk. Control groups were kept under 12-h light/dark cycle. After 4 wk, the gonadal weights and serum testosterone content were evaluated. The effects of nutrients on gonadal develop ment in rats differed between constant darkness groups (D-groups) and normal lighting groups (N-groups). Among the D-groups, the highest value for testes weight was observed under the normal protein, methionine added, low vitamin, low mineral and normal fat diet. The lowest value for testes weight was observed under the low protein, methionine added, normal vitamin, normal mineral and low fat diet. Among the N-groups, the highest value for testes weight was observed under the normal protein and no methionine diet, and the lowest value was observed under the low protein and no methionine diet. Among the D groups, the highest value for serum testosterone was observed under the normal protein and low mineral diet. In the N-groups, serum testosterone was not affected by nutritional factors. It became clear that the amounts of protein, methionine, vitamins, minerals, and oil which are necessary for the gonadal development of growing male rats change when kept in constant darkness.

The Effects of Calcium, Phosphorus, Magnesium, Sodium, and Zinc in Improving the Depression of Gonadal Development in Growing Male Rats Kept under a Disturbed Daily Rhythm-Investigations Based on the L16(215)-Type Orthogonal Array

“…We have previously reported that serum testosterone concentrations increase in response to a low-mineral diet in D-groups (1). In the present study, the minerals influencing serum testosterone concentrations were Ca, Mg, and Na.…”

“…We have previously reported that the depression of gonadal development of rats kept under constant darkness is mitigated by feeding a low-mineral diet (1). In the present study, an experiment was carried out to clarify which minerals come into play for the development of gonadal organs.…”

“…The effects of protein, methionine, vitamins, minerals, and oil on the gonads of rats kept under constant darkness have previously been reported ( 1 ). The results have shown that the depression of gonadal development in rats kept under constant darkness is mitigated by a normal-protein, methionine-added, low-vitamin, lowmineral, and normal-oil diet, and is accelerated by a low-protein, methionine-added, normal-vitamin, normal-mineral, and low-oil diet.…”

“…We have been using the condition of constant darkness as a model of disturbed daily rhythm ( 1,2 ). In general animal studies, the lighting condition is 12-h light/ 12-h dark, with the light working as an entrainer of circadian rhythm formation.…”

The Interactive Effect of Dietary Fat-Soluble Vitamin Levels on the Depression of Gonadal Development in Growing Male Rats Kept under Disturbed Daily Rhythm

“…In previous papers, we have reported the effects on rat gonadal development of protein, methionine, vitamins, minerals and oil ( 5 ), various minerals ( 6 ), various amino acids, an AIN-76 diet and an AIN-93G diet ( 7 ), the interaction between protein and vitamins ( 8 ), and water-and fat-soluble vitamins ( 9 ). We have demonstrated that a normal level of water-soluble vitamins and high level of fat-soluble vitamins diet, or a high level of water-soluble vitamins and low level of fat-solu-E-mail: hanai@bio.kanagawa-it.ac.jp ble vitamins diet mitigated the depression of gonadal development in rats kept under constant darkness ( 9 ).…”