THE GROWTH-PROMOTING HORMONE 



60 per cent of the injected rats, the basal metaboHsm (com- 

 puted in terms of the body surface) was reduced 10-40 per 

 cent. If the injections were stopped the basal metabolism 

 might remain low for 1-2 weeks. Szarka" (1933) obtained 

 different results, perhaps partly due to the presence of con- 

 siderable amounts of thyrotropic hormone in his extracts. He 

 found that an elevation (9-29 per cent) in the basal metabo- 

 lism of female rats occurred if the growth-rate was increased 

 by the injection of an extract of the pars glandularis. If no 

 growth-response was obtained or growth ceased, the basal 

 metabolism often fell (to 18 per cent below normal), provided 

 that the thyroid had not been removed; in the latter case, no 

 change in the basal metabolic rate was observed. 



The diuretic effects of some growth-promoting extracts 

 may be the result of a thyroid-stimulation (see chap. vii). 



4. The adrenals. — Evans and his colleagues (1932) con- 

 cluded that the growth-promoting extract used in their ex- 

 periments probably abolished the cachexia of hypophysec- 

 tomized rats because it favored the restoration of normal 

 function on the part of the cortex of the adrenal glands. The 

 extract also aided in the restoration of thyroid function. 

 Gonadotropic hormone(s) did not produce such effects. In 

 the experiments of Smith (1930), however, a cruder extract of 

 the pars glandularis caused growth in hypophysectomized 

 rats without altering the atrophic changes in the adrenal cor- 

 tex and in the thyroid. Evans, Pencharz, Meyer, and Simp- 

 son (1933) reported that the injection of a growth-promoting 

 extract of the pars glandularis did not favor the survival of 

 adrenalectomized rats. Similar results were obtained by Shu- 

 macker and Firor (1934), who found that if the pituitary was 

 implanted into adrenalectomized rats, there was no effect 

 on the loss of weight, the failure of growth, or the survival 

 period. 



" S. Szarka {Ber. ges. Physiol, exper. Pharm., LXXIV [1933] 189) appears to be 

 the same investigator who (A. J. Szarka) worked in Evans' laboratory. 



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