The effects of an oral contraceptive on plasma growth hormone and glucose tolerance in two strains of rats.

ABSTRACT

Effects of an oral contraceptive on plasma growth hormone and glucose tolerance were studied in two strains of rats, Sprague-Dawley, a normal strain, and BHE, a carbohydrate-sensitive strain. Ethynyl estradiol and norgestrel, combined in a dose representative of the clinical preparation of Ovral were given for 21 days. Plasma growth hormone was measured following sodium pentobarbital stimulation. In both strains fasting blood glucose levels were unchanged following oral contraceptive therapy, however, a strain difference in response to a glucose load was found. With contraceptive steroid treatment, Sprague-Dawley rats developed an impaired tolerance to glucose during the latter part of the glucose tolerance test. BHE control animals had an abnormal response to a glucose load which improved with oral contraceptive therapy. No significant correlation between growth hormone changes and changes in glucose tolerance during contraceptive steroid treatment were observed. Both strains of rats receiving oral contraceptives gained less weight than their controls, however, the difference was statistically significant only in the Sprague-Dawley strain.

ABSTRACT

PIP The effects of Ovral (norgestrel plus ethinyl estradiol) on plasma growth hormone (GH) levels and glucose tolerance were investigated in Sprague-Dawley and a carbohydrate-sensitive strain (BHE) of rats. Sodium pentobarbitol was used to stimulate GH production. Fasting blood glucose levels were not altered by treatment with Ovral in either strain. However, under a glucose load, Sprague-Dawley rats developed an impaired tolerance during the latter part of the glucose tolerance test, while treatment with the oral contraceptive improved an impaired response to glucose load in BHE animals. A good correlation between changes in GH and glucose tolerance during treatment could not be established. Sprague-Dawley rats had a significant (p less than .01) decrease in the rate of body weight increase compared with controls.