Influence of progesterone and oestrogen on growth and morphology of a transplantable rat uterine smooth muscle tumour (SMT-Y).
Tumours of uterine smooth muscle are poorly understood neoplasms in which the effects of steroid sex hormones are complex. The influence of progesterone and oestrogen on a transplantable rat uterine smooth muscle tumour line (SMT-Y) was investigated. Female F344 rats given subcutaneous transplants of tumour fragments developed tumours, 1.5-2 cm in diameter, and were then treated with progesterone (10 mg/rat) or 17 beta-oestradiol (50 mg/rat). Tumours in treated groups were compared with those in untreated controls. During a 9-week observation period after treatment, progesterone promoted tumour growth from 4 weeks, with increased numbers of proliferating cells. In contrast, oestradiol inhibited tumour growth from 6 weeks; the degraded tumours, consisting mainly of vacuolated neoplastic cells, had decreased numbers of proliferating cells and increased numbers of apoptotic cells, demonstrable by in-situ terminal deoxyribonucleotide transferase (TdT)-mediated dUTP nick labelling. Immunohistochemically, tumours in control and progesterone groups were labelled positively for alpha-smooth muscle actin (SMA) and desmin but not for vimentin, whereas the degraded tumours in the oestradiol group had reduced reactivity for SMA and desmin but an increased reactivity for vimentin. These results indicate that progesterone may act as a promoter for uterine smooth muscle tumour growth by stimulating mitotic activity, whereas oestrogen may have suppressive effects on tumour growth, accompanied by morphological changes.
Yamate
J
J
Department of Veterinary Pathology, College of Agriculture, Osaka Prefecture University, Japan.
Tsujino
K
K
Kumagai
D
D
Sato
K
K
Tsukamoto
Y
Y
Kuwamura
M
M
Kotani
T
T
Sakuma
S
S
LaMarre
J
J
D000818:Animals; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009368:Neoplasm Transplantation; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D018235:Smooth Muscle Tumor / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D013997:Time Factors; D014594:Uterine Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure
D014408:Biomarkers, Tumor; D004967:Estrogens; D011374:Progesterone