372 



CELLS, TISSUES, AND ORGANISMS 



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HYPOX RATS CONTROL 

 HYPOX RATS + G.H. 



for 4 day») 



40 80 120 160 



TIME- MINUTES 



200 



240 



Figure 8. The influence of chronic growth-hormone treatment on the 

 oxidation of palmitate-1-C^^ to C^'^Og by fed and fasted hypophysectomized 

 rats. (Frankhn and Knobil, 1961). 



growth-hormone administration, since a significant rise in the con- 

 centration of plasma FFA was observed only in this experimental 

 situation. 



Our finding that the absence of the pituitary gland does not in- 

 fluence the rate of utilization of labeled palmitate in vivo, as evidenced 

 by the respiratory output of labeled carbon dioxide is in accord with 

 earlier studies which similarly failed to demonstrate an inhibitory eflFect 

 of hypophysectomy on the utilization of octanoate, trilaurin, and tripal- 

 mitin (Geyer, Shaw, and Creep, 1950; Matthews et al., 1957). While the 

 above observations also suggest that, under the experimental conditions 

 employed, growth-hormone administration does not appear to stimu- 

 late the oxidation of palmitate to COo, the complexities of the in vivo 

 system make definitive interpretation difficult. The lack of detailed in- 

 formation concerning the effects of growth hormone on the pool size 

 and turnover rates of fatty acids is particularly prohibitive in this re- 

 gard. In an attempt to obviate some of these difficulties, we turned to a 

 simpler system, designed to study the effect of growth hormone on the 



