Growth hormone and sex steroid effects on serum glucose, insulin, and lipid concentrations in healthy older women and men.
BACKGROUND
With aging, GH, IGF-I, and sex steroid concentrations and glucose tolerance decrease, and body fat and serum lipids increase.


OBJECTIVE
The aim of the study was to assess GH and/or sex steroid administration effects on serum glucose, insulin, insulin sensitivity, and lipids in older individuals.


METHODS
A double-masked, 2 x 2 factorial, placebo-controlled, double-dummy design was used for the study.


METHODS
GH and/or sex steroid [transdermal estradiol plus oral medroxyprogesterone acetate in women (HRT); testosterone enanthate (T) in men] were administered for 6 months.


METHODS
Healthy, community-dwelling women (n = 57) and men (n = 74) ages 65-88 yr (mean, 72 yr) participated in the study.


METHODS
We measured serum glucose, insulin, and insulin sensitivity [quantitative insulin sensitivity check index (QUICKI) and insulin sensitivity index (ISI)] before and during an oral glucose tolerance test and lipid profiles.


RESULTS
In women, GH did not alter oral glucose tolerance test 120 min or 2-h area under the curve (AUC) glucose values, but it increased 120 min insulin and AUC insulin. There were no significant effects of HRT or GH+HRT. ISI and QUICKI decreased after GH. In men, GH increased 120 min and AUC glucose and insulin AUC. GH+T increased 120 min glucose and glucose and insulin AUCs. T alone did not affect glucose or insulin. ISI decreased after GH and GH+T, whereas QUICKI decreased after GH. GH in women and men and GH+T in men decreased QUICKI by 4 wk. In women, HRT decreased total cholesterol and low-density lipoprotein (LDL)-cholesterol, and GH decreased LDL-cholesterol. In men, total cholesterol decreased after T and GH+T. LDL-cholesterol decreased after GH and GH+T. GH increased serum triglycerides.


CONCLUSIONS
GH administration to healthy older individuals for 6 months increased insulin resistance with moderately beneficial effects on lipids.
Münzer
Thomas
T
Endocrine Section, Laboratory of Clinical Investigation, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
Harman
S Mitchell
SM
Sorkin
John D
JD
Blackman
Marc R
MR
D000279:Administration, Cutaneous; D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D004311:Double-Blind Method; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D015914:Estrogen Replacement Therapy; D005260:Female; D012739:Gonadal Steroid Hormones / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008055:Lipids / Q000097:blood*; D008297:Male; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage / Q000494:pharmacology*; D012016:Reference Values; D013739:Testosterone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology
D001786:Blood Glucose; D012739:Gonadal Steroid Hormones; D007328:Insulin; D008055:Lipids; D019382:Human Growth Hormone; D013739:Testosterone; D004958:Estradiol; C004648:testosterone enanthate; D017258:Medroxyprogesterone Acetate