Characterization and steroidal regulation of gonadotropin beta subunits in the male leopard frog, Rana pipiens.
In ranid frogs, the secretion of gonadotropins (GtHs), luteinizing hormone (LH), and follicle-stimulating hormone (FSH), is potently regulated by gonadal steroids. To better understand the gonadal regulation of GtHs at the molecular level, we elucidated the full-length cDNA sequences of LH and FSH beta subunits from the leopard frog, Rana pipiens. The cDNAs for LHbeta and FSHbeta were 1084 and 667 bp in size excluding the poly (A) tail, and encoded proteins of 138 and 127 amino acids, respectively. Using reverse-transcription polymerase chain reaction (RT-PCR), the messages for LHbeta and FSHbeta were found in the pituitary, but not in the brain, heart, kidney, or the liver. Semi-quantitative RT-PCR revealed a significant elevation of FSHbeta, but not LHbeta, in mature male R. pipiens 21 days after gonadectomy (GDX). 17beta-estradiol implant for 21 days in GDX male frogs significantly suppressed the levels of both LHbeta and FSHbeta transcripts, whereas 5alpha-dihydrotestosterone implant suppressed only the latter. Together, these results laid the groundwork for investigating gonadal regulation of GtHbeta subunits in a ranid frog. Importantly, these data also revealed differential feedback effects of an androgen and an estrogen upon GtHbeta expression.
Zhang
Lihong
L
School of Life Sciences, Zhongshan (Sun Yat-Sen) University, Guangzhou 510275, PR China.
Kessler
Ann E
AE
Tsai
Pei-San
PS
D000595:Amino Acid Sequence; D000704:Analysis of Variance; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000032:analysis; D013196:Dihydrotestosterone / Q000378:metabolism*; D004958:Estradiol / Q000378:metabolism*; D037201:Follicle Stimulating Hormone, beta Subunit / Q000235:genetics* / Q000378:metabolism; D037101:Luteinizing Hormone, beta Subunit / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D011894:Rana pipiens / Q000235:genetics* / Q000378:metabolism; D017385:Sequence Homology; D018709:Statistics, Nonparametric
D018076:DNA, Complementary; D037201:Follicle Stimulating Hormone, beta Subunit; D037101:Luteinizing Hormone, beta Subunit; D013196:Dihydrotestosterone; D004958:Estradiol