Oral contraceptives: effects on plasma insulin response to glucose and on the response to insulin and 2-deoxyglucose uptake by peripheral tissue

Oral contraceptive steroids, norethynodrel and mestranol, were fed to 11-wk-old female Sprague-Dawley rats, in combination and in quantities proportional to those used by women for contraceptive purposes. Three experiments were performed. The first experiment, demonstrated that 10 wk of treatment, impaired the animal's glucose tolerance, but not its insulin response to glucose. The second experiment demonstrated that 6 wk of steroid feeding, decreased the in vivo conversion of blood U-14C-labeled glucose into adipose tissue fatty acids and into diaphragm glycogen, although the effect on the diaphragm was not statistically significant. In the third experiment, it was found that the uptake of 2-deoxyglucose-1-14C by the adipose tissue removed from rats after 6 wk of treatment, was not different from that of control tissue, but the uptake by the hemidiaphragms was slightly lower.

Size and proteolytic enzyme activity of the pancreas of several species of vertebrate animals

Pancreas size and trypsin and chymotrypsin activities were determined for cattle, sheep, rats, mice, and chickens of various ages. Pancreas size per kilogram of live body weight was greater for the nonruminants than for the ruminants. Pancreas trypsin activity per milligram of pancreas dry matter was greater for ruminants than for nonruminants; however, activity per kilogram of body weight was greater for rats and mice than for chickens, which in turn was greater than for ruminants. Chymotrypsin activity was greater for rats and mice than for ruminants on the basis of both pancreas dry matter and body weight. In cattle, chymotrypsin activity per unit of pancreas dry matter was highest in the newborn calf, dropped to one-half that level within 1 week after birth, and then increased only slightly with age up to 1 year. The ratios of chymotrypsin to trypsin activities in the pancreas ranged from 0.39 to 1.20 in the ruminants, except for the newborn calf (1.60), and were greater than 2.0 for the other species. Pancreas size and trypsin and chymotrypsin activity were proportional to body weight1.0 with intraspecies comparisons, and proportional to body weight0.73–0.84 with interspecies comparisons.