Sites and Mode of Action of Growth Hormone 



251 



3. Test meal studies: growth hormone was measured for six hours following the 

 ingestion of 0.71 g. of glucose per kilogram body weight. Here plasma nonesterified 

 fatty acids (N.E.F.A.) were also monitored. 



4. Surgery: the hormone levels were determined at short intervals throughout 

 various surgical procedures. 



Blood sugar was measured in all samples. Bone age was assessed using the Greu- 

 LiCH and Pyle atlas (1959) and sexual maturation scores (S.M.S.) were made using 

 Tanner's method (1962). Estimations of the urinary 17-Hydroxycortico-steroids 

 during diurnal studies showed that these investigations did not produce a stress 

 response. 



Results 



The graphs, which are representative of our findings in the whole series, show 

 plasma human growth hormone levels in j_i mg. per millilitre of plasma. Arrows 



8 !2 f 6 12 V 



am noon pm pm midnight am 



20 



Subject 5 Cf 

 Age 72 %2 



done age 77 %2 

 SMS r 



^0 £ndocrinopafhy 

 Resting in oed 



F/asma 

 HGH 10- 

 ^ mg/ml 



steep B'fasf Dinner Supper 



Fig. 1. Diurnal Growth Hormone Study. Subject 5 



indicate food intake and the solid bars record the hours of sleep. The base line is 

 drawn at the threshold of sensitivity of the assay as used in that particular study. 

 In subject five (Fig. 1) the plasma 



Subjected AgenWi2 Bon Age 13 ^/iz SMS v 

 /K? Endocrinopaff)y Resting in bed 



G. H. levels were very low through- 

 out the day; but at 9.10 p.m., four 

 hours after supper, a level of 14.5 

 //mg. ml. was recorded. 



Subject eight (Fig. 2) was a 14 

 years and 8 months old boy, bone age 

 13' 2 years and S.M.S. four. During 

 the daytime he produced two high 

 levels, viz. before lunch (> 30 //mg./ 

 ml.) and before supper (4.3 //mg./ml.). 

 In each case it fell rapidly to the 

 base line following the respective 

 meals. During sleep the highest level 

 (53 //mg./ml.) was recorded. 



During the night the total secretion of growth hormone (Fig. 3) was many times 

 greater than that for the same subjects during the daytime. Immediately following 



B'fasf Lunch Tea Supper Sleep 



Fig. 2. Diurnal Growth Hormone Study. Subject S 



