Role of insulin in the progression of ovarian sex cord stromal tumors in rats.
OBJECTIVE
This study examined the effect of insulin on sex cord stromal tumors in the rat.


METHODS
Sex cord stromal tumors were induced by transplantation of ovaries under the splenic capsule of ovariectomized rats (Lewis-inbred). These tumors were then transplanted into new inbred rats. Hyperglycemic conditions were induced by treatment with streptozotocin (STZ, which selectively destroyed pancreatic islet cells) and hypoglycemic conditions by treatment with a subcutaneously implanted insulin pump (Alzet). The animals were killed 28, 56, and 84 days later. Tumor growth, animal weight, food and water consumption, and serum concentrations of glucose, FSH, LH, and estradiol were measured.


RESULTS
Treatment with STZ and insulin with osmotic Alzet pumps induced continuous hypoglycemic and hyperglycemic conditions, respectively. No significant influence of the hypoglycemic or hyperglycemic status on tumor growth was measured during the first 28 and 56 days. Eighty-four days after transplantation and substitution of 1 or 2 IU/100 g body weight/d insulin, there was a significant stimulation of tumor growth (2.2-fold and 2.7-fold, respectively). In hyperglycemic animals (treated with STZ), no influence on tumor growth was found in comparison with the controls.


CONCLUSIONS
This study confirms that hyperinsulinemic conditions contribute to the progression of tumors.
Dragonas
Charalampos
C
Department of Internal Medicine V, University of Erlangen-Nuremberg, Klinikum Nuremberg, 90419, Nuremberg, Germany.
Mueller
Andreas
A
Maltaris
Theodoros
T
Kraemer
Peter
P
Dimmler
Arno
A
Jaeger
Wolfram
W
Beckmann
Matthias W
MW
Dittrich
Ralf
R
D000818:Animals; D014408:Biomarkers, Tumor / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D018450:Disease Progression; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006946:Hyperinsulinism / Q000150:complications*; D007328:Insulin / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood; D009368:Neoplasm Transplantation; D010052:Ovariectomy; D051381:Rats; D011917:Rats, Inbred Lew; D018312:Sex Cord-Gonadal Stromal Tumors / Q000097:blood / Q000209:etiology* / Q000378:metabolism* / Q000473:pathology; D013311:Streptozocin; D013997:Time Factors
D014408:Biomarkers, Tumor; D001786:Blood Glucose; D007328:Insulin; D013311:Streptozocin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone