Effect of Deficient Diets on Corticosteroid Synthesis by Rat Adrenals in Vitro and Its Relationship to Infections With Nippostrongylus Brasiliensis

Abstract

Rats were fed on a low protein (LP) and a glucose\p=m-\filter paper (GFP) diet; they were then infected with 1000 larvae of the nematode worm Nippostrongylus brasiliensis (Travassos, 1914) and killed 5 or 10 days later.The adrenals of male and female rats on the GFP diet for 21 days showed atrophy and so did those of female rats on the LP diet for 42 or 56 days. The adrenals of male rats on the LP diet for 21 days were hypertrophic.Referred to body weight, the adrenal weights of male rats on both diets were higher than those of the controls, the weights of the adrenals of female rats on the deficient diets were lower.Adrenal weight and adrenal weight as a percentage of body weight were shown to bear no relationship to corticosteroid production in vitro, since the capacity for corticosteroid synthesis in vitro was increased in rats on the GFP diet only.Significantly more parasites were found in the intestine after 5, but not after 10 days on both deficient diets suggesting that the deficient diets increased the susceptibility of the rats on initial contact with the parasite and before the development of acquired resistance. Later more parasites were lost by the rats on the deficient diets than from controls. These findings were not related to changes in the rate of corticosteroid synthesis.The effects of stress, and the administration of cortisone or corticotrophin on host\p=m-\parasite relationships is discussed in relation to the results of the present experiments. It is concluded that though these factors can increase susceptibility and lower acquired resistance, the effect on susceptibility can also be produced independently by severe dietary deficiency.

The effect of a low protein diet and a glucose and filter paper diet on the course of infection ofNippostrongylus brasiliensis

“…The effect of the quality of protein as distinct from quantity revealed that animals fed plant protein (arachin) instead of animal protein (casein) developed a lower degree of acquired resistance to N. brasiliensis (Barakat, 1948). The Agricultural Research Council low protein diet used in the present experiments was found to reduce acquired resistance (Wells, 1962) and increase susceptibility (Clarke, 1967). There is general agreement by the above authors that the deficient diets cause changes in the host's physiology rather than affecting the parasites directly.…”

“…Twohy, 1956). Rats were maintained before and after infection as described elsewhere (Clarke, 1967).…”

“…diets compared with the control diet (Oxoid diet 86) is shown in Table 1. Details of the preparation of the diets have been given in Clarke (1967). Both deficient diets were fed ad lib.…”

“…The effect of cortisone in suppressing inflammation is also established (Menkin, 1960). However, it has been shown that there is no direct connexion between malnutrition, corticosteroid level and parasitism (Clarke, 1967). Although malnutrition may result in an increase in corticosteroid level, severe dietary deficiency can cause increased susceptibility independently of this.…”

Endocrine responses of protein-malnourished rats infected with Nippostrongylus brasiliensis (Nematoda)

“…The adrenal glands were removed at post mortem examination and 1 from each rat was dried at 100 °C to constant weight. Earlier work by Clarke (1969) paid attention to the size and physiology of the adrenal glands of rats infected with N. brasiliensis, but she used markedly different dietary and experimental conditions.…”