Developmental changes of testicular activin and FSH receptor mRNA and plasma FSH and inhibin levels in the rat.
To investigate the changes in the FSH receptor and the activin receptor during sexual maturation in rat testes, we examined the mRNA levels of the receptors by Northern blot analysis. With a full length rat activin receptor cRNA probe in this study, Northern blot analysis revealed two activin receptor mRNAs (6Kb and 3Kb) in testes. The large messenger (6Kb) was low on day 7, and gradually increased by day 35. On the other hand, the small messenger (3Kb) was low on day 7, began to increase on day 21, and had increased dramatically by day 35. Therefore, compared with our previous data, developmental changes in the mRNA of the activin receptor of male and female gonads showed certain differences. The expression of 3Kb activin receptor mRNA in rat testis may be relevant to the stimulated spermatogenesis in this period. 2.4Kb and 5.5Kb FSH receptor mRNA were revealed on day 7 and decreased to 80% on day 14 and remained at the same level. The Scatchard plots of FSH binding data showed that the binding affinities of testicular FSH were constant at each stage of development. Changes in the mRNA level in FSH receptor were followed by changes in the concentration of FSH receptor in testis. The rise in the plasma FSH level was concomitant with the decrease in the plasma inhibin level by day 14.
Ito
I
I
Department of Obstetrics and Gynecology, Gunma University School of Medicine, Japan.
Minegishi
T
T
Hasegawa
Y
Y
Shinozaki
H
H
Nakamura
K
K
Igarashi
S
S
Nakamura
M
M
Miyamoto
K
K
Ibuki
Y
Y
D029404:Activin Receptors; D000818:Animals; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D007265:Inhibins / Q000097:blood*; D008297:Male; D010053:Ovary / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D011962:Receptors, FSH / Q000235:genetics*; D017978:Receptors, Growth Factor / Q000235:genetics*; D012741:Sexual Maturation; D013737:Testis / Q000378:metabolism*
D012333:RNA, Messenger; D011962:Receptors, FSH; D017978:Receptors, Growth Factor; D007265:Inhibins; D005640:Follicle Stimulating Hormone; D029404:Activin Receptors