Bony Tareets of Non-"skeletal" Hormones 



223 



several tissues has already supplied abundant evidence of the validity and usefulness 

 of these concepts. What remains to be done is to examine how far these ideas have 

 been applied to studies of the effects of the "non-skeletal" hormones on the potential 

 targets in bone. 



Here the field of investigation remains largely untouched. Although a number of 

 laboratories have been actively engaged in exploring effects of parathyroid hormone 

 on skeletal metabolism the only avail- 

 able data with respect to other hor- 

 mones are only just sufficient to in- 

 dicate that profound and highly im- 

 portant effects will be found when 

 someone undertakes to search for 

 them. The kinds of biochemical stu- 

 dies so far available are illustrated in 

 the last 3 diagrams. 



Fig. 6 although originally pub- 

 lished by Dr. Vaes and me in 1962 

 remains, to my knowledge, the only 

 demonstration of its kind in the lite- 

 rature. The choice of hormones was 

 determined by information suggesting 

 that insulin enhanced protein synthe- 

 sis and amino-acid uptake in dia- 

 phram while Cortisol and thyroxine 

 were examined because of the bony 

 lesions which seem to occur with ex- 

 cesses of each. Significant stimulation 

 of glycine uptake by insulin and in- 

 hibition by both thyroxine and Cor- 

 tisol were observed in the experiments 

 with rat bone — effects which in the 

 case of Cortisol, at least, seemed to fit 

 with available information regarding 

 bony changes in hyperadrenocortical 

 states. Nothing further was done at 

 that time, but recently we have begun 

 some further experiments using pigs 

 to explore the details of these effects. 

 To our surprise, only the effects of 

 insulin have been possible to confirm. 

 Both cortisone and thyroxine appear 

 to stimulate rather than to inhibit 

 aminoacid uptake and collagen syn- 

 thesis in this species (Nichols, un- 

 published experiments). While the reasons for these differences are not clear they in- 

 dicate clearly the importance of variations between species and tissues in determining 

 the nature of hormone effects even at the molecular level! 



2 ■ 



10<0I 



Fig. 7. Contrasting effects of estradiol treatment on the 

 incorporation of glycine-l-^C into COo (clear bars) and 

 organic matrix (shaded bars) of metaphyseal bone from 

 male rats and mice. Rats received estradiol valerate in 

 oil s.c, 2.0 mg. in 4 doses 6 days apart, mice 2 mg. in 

 4 doses 6 days apart. Controls received oil s.c. only. 

 (Recalculated from data of Vaes and Nichols 1962.) 



