Gonadotropins and inhibins along the development of a luteinized rat ovarian tumor.
Luteinized intrasplenic ovarian tumors develop in response to high circulating gonadotropins. The relationship between tumor development, gonadotropins and inhibins was studied. Tumor-bearing animals were sacrificed weekly along the first 6 weeks of development. Inhibins were measured by enzyme-linked immunosorbent assay (ELISA), serum gonadotropins, GH and IGF-1 by RIA. Inhibin subunit mRNAs were determined by Northern blot. Tumor histology was examined. Ovarian grafts grew significantly along development. LH increased ten-fold on week 1; a further significant increment was observed on week 3. FSH peaked on weeks 1 and 2 and fell significantly thereafter. Serum inhibins markedly increased on weeks 3-5. Tumor inhibin A content and mRNA levels for alpha and beta A subunits also increased on week 3. Inverse correlations between inhibins and FSH and direct correlations between inhibins and LH were observed. Tumor inhibin A and IGF-1 contents correlated significantly. Increasing levels of luteinization were observed along tumor development. These luteinized tumors develop mainly in response to LH, since growth continues under FSH inhibition. The active inhibin secretion and the positive correlation between inhibins and LH suggests that LH may be the main driving force behind this production, while growth factors produced by the gonads may also participate in their regulation.
Hockl
P
P
Lab. de Neuroendocrinologia, Instituto de Biologia y Medicina Experimental (IByME) CONICET, V. de Obligado 2490, Buenos Aires 1428, Argentina.
Sorianello
E
E
Chamson-Reig
A
A
Ballerini
G
G
Campo
S
S
Groome
N
N
Lux-Lantos
V
V
Libertun
Carlos
C
D000818:Animals; D002455:Cell Division; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006062:Gonadotropins / Q000097:blood / Q000502:physiology*; D007265:Inhibins / Q000097:blood / Q000235:genetics / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D034461:Luteinization / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood / Q000502:physiology; D010051:Ovarian Neoplasms / Q000209:etiology* / Q000473:pathology; D021122:Protein Subunits / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley
D006062:Gonadotropins; D021122:Protein Subunits; D012333:RNA, Messenger; C422362:inhibin A; D007265:Inhibins; D007334:Insulin-Like Growth Factor I; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone