Postmenopause-like bone loss by mammary carcinoma Walker256/S which secretes luteinizing hormone-releasing hormone.
When Walker 256/S carcinosarcoma (W256/S) was subcutaneously inoculated into the back of mature female Wistar Imamichi rats (10-week-old), the tumor grew rapidly and caused increases in the urinary excretions of calcium and hydroxyproline, without changes in the serum concentrations of calcium and inorganic phosphorus. Furthermore, osteoporosis-like changes in the femurs and decrease in uterus weight were observed, as previously reported for W256/S-bearing young rats. In the healthy mature female rats, the estrus cycle passed through four stages (proestrus, estrus, metestrus and diestrus) within 4 to 5 days, with a peak of serum estradiol and progesterone levels in the proestrus stage. On the other hand, after subcutaneous inoculation of W256/S into the rats, the estrus cycle tended to pause upon the metestrus or diestrus stage, accompanied with significantly low estradiol and progesterone levels in serum. W256/S tumor produced and secreted luteinizing hormone-releasing hormone (LH-RH). In conclusion, it seems that the ectopical secretion of LH-RH from the tumor resulted in the decrease in the secretion of gonadotropic hormones, following low level of sex hormones and stopping the estrus cycle. Therefore, W256/S-bearing rats may be a model for osteoporosis of hypoovarianism or postmenopause.
Waki
Y
Y
Department of Pharmacology and Pharmaceutics, Graduate School of Natural Science and Technology, Kanazawa University, Japan.
Miyamoto
K
K
Yamamoto
S
S
Saitoh
Y
Y
Kasugai
S
S
Ohya
K
K
D000469:Alkaline Phosphatase / Q000097:blood / Q000652:urine; D000818:Animals; D001483:Base Sequence; D001862:Bone Resorption; D002118:Calcium / Q000097:blood / Q000652:urine; D002279:Carcinoma 256, Walker / Q000378:metabolism / Q000473:pathology*; D017931:DNA Primers; D004958:Estradiol / Q000097:blood; D004971:Estrus; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D009368:Neoplasm Transplantation; D009929:Organ Size; D010758:Phosphorus / Q000097:blood / Q000652:urine; D011374:Progesterone / Q000097:blood; D051381:Rats; D017208:Rats, Wistar
D017931:DNA Primers; D010758:Phosphorus; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D004958:Estradiol; D000469:Alkaline Phosphatase; D002118:Calcium