208 /. /. Christian 



turally secreted corticoids of the zona fasciculata and to discuss the actions 

 of these hormones as a class. 



(2) Adiojis of the fascicular hormones. Hydrocortisone, cortisone, 

 and corticosterone have important effects on carbohydrate metaboHsm 

 and therefore are classed loosely as carbohydrate-active corticoids. They 

 have in common either a hydroxyl group or ketonic oxygen at the carbon-11 

 position, and those with the most pronounced effects on carbohydrate 

 metabolism, hydrocortisone and cortisone, have a hydroxyl group on the 

 C-17 of the steroid nucleus. Corticosterone has a weaker action on carbohy- 

 drate metabolism than hydrocortisone or cortisone (Dorfman, 1949; Ingle, 

 1950; Parmer et al., 1951; Santisteban and Dougherty, 1954; Dougherty 

 and Schneebeli, 1955; Kass et al., 1955; Noble, 1955) , but it has appreciably 

 more effect on salt-electrolyte metabolism than either of the others (Noble, 

 1955; Farrell et al., 1955; Jones, 1957) . Because of these facts, the relatively 

 small amounts of hydrocortisone which are normally secreted by the adre- 

 nals of mice and rats, along with corticosterone, have been held responsible 

 for most of the carbohydrate-active corticoid activity, such as involution 

 of the thymus, which has been observed in these animals (Wilson etal., 

 1958). The designation "carbolwdrate-active corticoids" for this group of 

 steroids by no means reflects all their activities. These corticoids have sup- 

 pressive effects to varying degrees on inflammation and therefore are 

 classified also as anti-inflammatory (antiphlogistic) hormones (Selye, 1950; 

 Dougherty 1953) . As a class they have profound effects on protein metabo- 

 lism, fat metabolism, growth, oxygen consumption, and a number of other 

 physiological functions (Noble, 1955; Jones, 1957). Hydrocortisone and 

 cortisone are the most powerful of the fascicular carbohydrate-active 

 corticoids and corticosterone the least powerful with respect to the enume- 

 rated activities (cf. above), although cortisone is not produced in bio- 

 logically important quantities in any of the species so far investigated 

 (Bush, 1953; Nelson, 1955). As a general rule, the degree of activity of a 

 corticoid on carbohydrate metabolism is related inversely to its sodium-re- 

 taining ability. Finally, it should be noted that other steroids may affect the 

 actions of the corticoids; for example, testosterone and estradiol potentiate 

 the anti-inflammatory action of the carbohydrate-active corticoids (Tauben- 

 haus, 1953), and testosterone enhances the thymolytic activity of cortisone 

 (Selye, 1955; Dorfman and Shipley, 1956) . 



The carbohydrate-active corticoids, secreted by the zona fasciculata, will 

 maintain life in adrenalectomized mammals (Ingle, 1950) ; nevertheless the 

 exact functions of the adrenocortical hormones in the intact normal animal 

 are difficult to delineate precisely, as these hormones are integral elements 

 in a complex system of endocrine and neural responses which form a feed- 



