Effect of ascorbic acid on guinea pig adrenal adenylate cyclase activity and plasma cortisol.

Intra-adrenal ascorbic acid (AsA) concentrations exert a braking or modulating effect upon steroid release. Because changes in steroidogenesis are mediated through alterations in adenylate cyclase activity (ACL), the effect of varied AsA plasma concentrations on guinea pig adrenal ACL activity and plasma cortisol was studied. Forty-two male guinea pigs were randomly allocated to the following seven groups: controls, scorbutic, and groups given 0.1, 5, 10, 20 or 100 mg ascorbic acid/100 g body weight, respectively. Scorbutic animals had very low levels of AsA in comparison to control animals. Plasma AsA levels increased as AsA dose increased. The levels of AsA in the group given 0.1 mg AsA were higher than in controls. Basal adenylate cyclase activity did not vary significantly among animal groups. In contrast, values for NaF-stimulated ACL activity showed a progressive decrease with increasing AsA doses. A highly significant correlation was found between decreasing ACL activity and increasing plasma AsA concentrations. On the other hand, NaF-responsive ACL activity was higher in scorbutic animals than in any other group. Higher mean cortisol values were found in the scorbutic group than in the controls, correlating with high levels of NAF-stimulated ACL activity. Higher mean cortisol values were also found in the group given 0.1 mg AsA although ACL activity in this group was not affected. This finding, coupled with reduced ACL activity in these groups, is consistent with the inhibitory effect of a megadose of AsA on production of cortisol from the adrenal. The above data may suggest that differing plasma concentrations of AsA regulate in vivo steroidogenesis by altering the activity of the membrane-bound enzyme adenylate cyclase.

Effect of ascorbic acid (vitamin C) on the epiphyseal plate of young guinea pigs receiving prednisolone.

The effect of excess ascorbic acid on the epiphyseal plate of young guinea pigs receiving prednisolone over a period of 28 days has been investigated. The results show that the structural and morphologic changes caused in the epiphyseal plate of the animals receiving prednisolone are prevented by the simultaneous administration of excess ascorbic acid. These data are consistent with the hypothesis that pharmacological doses of ascorbic acid given concurrently to children receiving prolonged treatment with corticosteroids may prevent suppression of growth in these children.

Duplication of the pylorus: an elusive diagnosis.

A 20-day old female with symptoms of intermittent gastric outlet obstruction since the third day after birth was subjected to surgical exploration. Laparotomy revealed duplication of the pylorus communicating with a normal gastric cavity. The patient was successfully treated by excising the wall separating the duplication from the pylorus. Five cases of pyloric duplication reported so far in the English literature are reviewed.

Renal amyloidosis with nephrotic syndrome in a child suspected of having idiopathic pulmonary hemosiderosis.

A case of renal amyloidosis with nephrotic syndrome in a 12-year-old girl suffering from a chronic pulmonary disease is reported. Data from this patient's history, laboratory examination and radiographic evaluation of the pulmonary lesions favour the diagnosis of a long-standing idiopathic pulmonary hemosiderosis. A possible etiologic relationship between the pulmonary lesions and amyloid deposition in the kidney may be assumed.

Urinary hydroxyproline values following continuous and intermittent administration of prednisolone in children.

The administration of 2 mg/kg body weight of prednisolone daily in divided doses to 5 healthy children aged 5-7 years resulted in a significant decrease in the amount of total urinary hydroxyproline (HOP) which was restored to pretreatment levels two weeks after discontinuation of the drug. On the other hand, the administration of 2 mg/kg body weight of prednisolone in a single dose on alternate days (every-other-day) to two children and for a period of 10 days caused insignificant alterations in the amount of urinary HOP.

Inhibitory effect of ascorbic acid (vitamin C) on cortisol secretion following adrenal stimulation in children.

Measurements of plasma cortisol values before and at 4 and 6 hours after intramuscular administration of a depot preparation of synthetic b1-24 corticotrophin were carried out in 12 healthy children (group B) before, as well as on the 5th day of continuous ascorbic acid (AA) administration (1 g t.i.d. orally). Comparison of the results in group B with those of 8 healthy children similarly treated with corticotrophin but not given AA (group A) showed that, on the 5th day of AA administration the mean cortisol values after ACTH were significantly lower than the corresponding values in group A (p less than 0.02), or the post-ACTH values in group B observed on the 1st experimental day, i.e., before AA administration (p less than 0.001). On the other hand, AA administration had no significant effect on the fasting plasma cortisol values. These data suggest that AA excess following adrenal stimulation with ACTH exerts an inhibitory effect on cortisol secretion and consequently it may be of no benefit in conditions of stress.