Morphometric evaluation of effects of two sex steroids on mammary gland of female rats.
OBJECTIVE
The purpose of this study was to evaluate the effects of two sex hormones on normal mammary gland of female rats.


METHODS
Forty 250-day-old female rats, 20 of them with offspring and 20 not, were ovariectomized and, divided into 4 subgroups in order to receive one of the following subcutaneous treatment: estradiol benzoate (EB), medroxyprogesterone (MPA), EB+MPA or placebo, for 10 weeks. After treatment, mammary glands were studied with optical microscope. Whole gland, lobule, ductule and lumen compartments were evaluated by morphometric methods. Also a qualitative evaluation were performed seeking for secretion, microcalcification and trophic status.


RESULTS
It was found that (a) MPA-only and placebo were similar for all parameters; (b) the same between EB and EB+MPA; (c) EB and EB+MPA increased lobule, ductule and lumen compartments significantly compared to MPA-only or placebo; (d) EB increased epithelium but without significance and EB+MPA increased it significantly compared to placebo or MPA; (e) EB and EB+MPA incremented secretion.


CONCLUSIONS
In normal mammary gland of female rats: progestin action depends on estrogen presence. MPA does not revert estrogen-dependent proliferation, but it magnifies estradiol effect. Both EB and EB+MPA stimulate differentiation. Rats without offspring presented a greater epithelial proliferation under treatment with these sex hormones.
Pompei
Luciano M
LM
Department of Obstetrics and Gynecology, São Paulo University, Medicine School, São Paulo 04646001, Brazil. gindoclmp@hotmail.com
Carvalho
Filomena M
FM
Ortiz
Silvia C B C
SC
Motta
Milena C
MC
Cruz
Robison J
RJ
Melo
Nilson R
NR
D000818:Animals; D016022:Case-Control Studies; D049109:Cell Proliferation / Q000187:drug effects; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D016014:Linear Models; D008321:Mammary Glands, Animal / Q000187:drug effects* / Q000473:pathology; D008525:Medroxyprogesterone / Q000008:administration & dosage / Q000494:pharmacology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
C074283:estradiol 3-benzoate; D004958:Estradiol; D008525:Medroxyprogesterone