Characterization of the Chicken Follicle-Stimulating Hormone Receptor (cFSH-R) Complementary Deoxyribonucleic Acid, and Expression of cFSH-R Messenger Ribonucleic Acid in the Ovary1

Abstract

Studies were conducted to characterize the chicken (c) FSH receptor (R) cDNA, and to evaluate expression of cFSH-R mRNA in the hen ovary at known stages during follicle development. A total of 2.5 kb of nucleic acid sequence including the complete cFSH-R coding region was isolated by a combination of the reverse-transcription polymerase chain reaction and 5'- and 3'-rapid amplification of cDNA ends techniques. Overall, the nucleic acid sequence homology of the cFSH-R cDNA coding region is 71.8% and 72.2% compared to the rat and bovine FSH-R, respectively, while the deduced amino acid sequence identity for the receptor protein (693 amino acids) is 71.9% and 72.4%, respectively. By comparison, the cFSH-R nucleic acid and amino acid sequences are 60.1% and 49.4% identical to the respective cLH-R sequences. Northern blot analysis detected a single 4.3-kb cFSH-R mRNA transcript, which was selectively expressed in ovarian (granulosa, theca, and stromal) tissues, but not the oviduct, adrenal, liver, muscle, or brain. As the follicle developed from the prehierarchical (6- to 8-mm diameter) to the largest preovulatory (F1 follicle) stage, cFSH-R mRNA levels progressively declined within both the granulosa and theca layers (p < 0.05). Moreover, cFSH-R mRNA levels were lower in whole atretic than in morphologically normal 3- to 5-mm follicles (p = 0.0015). The pattern of cFSH-R mRNA expression within the granulosa layer during follicle development was notably different from that of the recently reported cLH-R, in that cLH-R mRNA levels increase to become readily detectable coincident with dramatically increased steroidogenic capacity during the last few days before ovulation of the follicle. On the other hand, highest levels of cFSH-R mRNA in 6- to 8-mm (prehierarchical) follicles were consistent with a role for the cFSH-R in maintaining the viability of prehierarchical follicles and in initiating granulosa cell differentiation at the time when follicles are selected into the preovulatory hierarchy.

Modulatory effects of gonadotrophins and insulin-like growth factor on the secretion of inhibin A and progesterone by granulosa cells from chicken preovulatory (F1-F3) follicles

“…A decrease in FSH responsiveness as follicles move up the preovulatory hierarchy is consistent with previous observations: You et al (1996) reported a significant reduction in expression of FSH receptor mRNA in granulosa cells from F3 to F1 follicles, which corresponded to a decreased FSH receptor binding, without a change in receptor affinity (Ritzhaupt and Bahr, 1987). Calvo and Bahr (1983) also found higher FSH-stimulated adenylyl cyclase activity in granulosa cells from smaller preovulatory follicles.…”

“…Granulosa cell LH receptor mRNA expression is similar in F3 to F1 follicles (Johnson et al, 1996). Moreover, at the stage of the ovulatory cycle at which granulosa cells were collected in the present study (approximately 4 h after ovulation of the previous F1 follicle), Calvo et al (1981) found no inter-follicle difference in basal and LH-stimulated granulosa cell adenylyl cyclase activity; increased responsiveness of the adenylyl cyclase system to LH was not demonstrated in the F1 and F2 granulosa layers until 12 h before the expected time of ovulation of the F1 follicle (some 8 h later than the time of follicle collection in the present study).…”

Bone morphogenetic protein 2 inhibits FSH responsiveness in hen granulosa cells

“…Although it has not yet been established whether this loss of FSH responsiveness occurs prior and/or subsequent to cAMP formation, there is a recent report that BMP2 (and BMP4) inhibits both FSH-and forskolin-induced progesterone production and cAMP synthesis in rat granulosa cells (Inagaki et al 2009). Importantly, highest levels of FSHR mRNA during follicle development occur in the hen granulosa cells from this cohort of prehierarchal follicles of 6-8 mm diameter (You et al 1996. Accordingly, it is evident that elevated FSHR mRNA (and presumably FSHR protein) by itself is not sufficient to initiate follicle selection and granulosa cell differentiation.…”

Bone morphogenetic protein 6 promotes FSH receptor and anti-Müllerian hormone mRNA expression in granulosa cells from hen prehierarchal follicles

“…During hen follicle development, FSHR mRNA in the granulosa layer is expressed at highest levels within the cohort of 6-8 mm follicles (You et al 1996). Moreover, it has been reported that within this prehierarchal cohort, a single follicle typically exhibits a higher level of FSHR expression compared with the others, and we have hypothesized that this represents the most recently selected follicle (Woods & Johnson 2005).…”