Response of hen pre-recruitment ovarian follicles to follicle stimulating hormone, in vivo

Kahina Ghanem, Alan Leslie Johnson

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

In laying hens, pre-recruitment ovarian follicles (1–8 mm diameter) are arranged as a continuum of size and predicted maturity. Cyclic recruitment of a pre-recruitment follicle to the preovulatory stage begins, in part, by the ability of the granulosa cell (GC) layer to initiate responsiveness to follicle stimulating hormone- (FSH-) induced cyclic adenosine monophosphate. The objective of this study was to determine if increased circulating concentrations of FSH during the ovulatory cycle increase the number of recruited follicles, in a dose-dependent manner. Equine chorionic gonadotropin (eCG) was initially tested due to its FSH-like properties and long half-life. Laying hens were injected, i.m., with 0 or 100 IU eCG, and ovaries were collected 29 h later. Recruited follicles were initially identified based on incorporation of yellow yolk and a weight of 250–900 mg. Recruitment was subsequently confirmed by both incubating the GC layer for 3 h with recombinant human (rh) FSH to establish FSH-responsiveness and quantifying P450 side-chain cleavage enzyme (CYP11A1) mRNA. Additional hens were injected with 0, 30, 75, and 300 IU eCG to establish a dose–response. Because eCG exhibits some luteinizing hormone activity, FSH-induced recruitment was evaluated by injecting 0.1, 0.33, 0.66, 1 or 3.3 µg rhFSH. Ovaries were collected 29 h post-injection, and expression of CYP11A1 mRNA was quantitated in GCs from recruited and pre-recruitment follicles. One hundred IU eCG induced recruitment of 2–8 follicles compared to a single follicle in control hens. In contrast to pre-recruitment follicles, incubated GC from eCG-recruited follicles had initiated differentiation, indicated by increased CYP11A1 and rhFSH-induced STAR mRNA and progesterone. Equine CG and rhFSH each increased the number of recruited follicles in a dose-dependent manner. Further, CYP11A1 mRNA was significantly increased in GC layers from recruited, compared to non-recruited, follicles. We conclude that FSH-responsiveness within the GC layer of each pre-recruitment follicle increases with follicle size, and propose that this establishes the order of daily follicle recruitment.

Original languageEnglish (US)
Pages (from-to)41-47
Number of pages7
JournalGeneral and Comparative Endocrinology
Volume270
DOIs
StatePublished - Jan 1 2019

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Equine Gonadotropins
Ovarian Follicle
follicle-stimulating hormone
ovarian follicles
Follicle Stimulating Hormone
Chorionic Gonadotropin
Cholesterol Side-Chain Cleavage Enzyme
Granulosa Cells
hens
equine chorionic gonadotropin
granulosa cells
Messenger RNA
Ovary
Human Follicle Stimulating Hormone
laying hens
Luteinizing Hormone
Cyclic AMP
Horses
Progesterone
Half-Life

All Science Journal Classification (ASJC) codes

  • Animal Science and Zoology
  • Endocrinology

Cite this

@article{a620cf343dcd415b9653aa73f048b50c,
title = "Response of hen pre-recruitment ovarian follicles to follicle stimulating hormone, in vivo",
abstract = "In laying hens, pre-recruitment ovarian follicles (1–8 mm diameter) are arranged as a continuum of size and predicted maturity. Cyclic recruitment of a pre-recruitment follicle to the preovulatory stage begins, in part, by the ability of the granulosa cell (GC) layer to initiate responsiveness to follicle stimulating hormone- (FSH-) induced cyclic adenosine monophosphate. The objective of this study was to determine if increased circulating concentrations of FSH during the ovulatory cycle increase the number of recruited follicles, in a dose-dependent manner. Equine chorionic gonadotropin (eCG) was initially tested due to its FSH-like properties and long half-life. Laying hens were injected, i.m., with 0 or 100 IU eCG, and ovaries were collected 29 h later. Recruited follicles were initially identified based on incorporation of yellow yolk and a weight of 250–900 mg. Recruitment was subsequently confirmed by both incubating the GC layer for 3 h with recombinant human (rh) FSH to establish FSH-responsiveness and quantifying P450 side-chain cleavage enzyme (CYP11A1) mRNA. Additional hens were injected with 0, 30, 75, and 300 IU eCG to establish a dose–response. Because eCG exhibits some luteinizing hormone activity, FSH-induced recruitment was evaluated by injecting 0.1, 0.33, 0.66, 1 or 3.3 µg rhFSH. Ovaries were collected 29 h post-injection, and expression of CYP11A1 mRNA was quantitated in GCs from recruited and pre-recruitment follicles. One hundred IU eCG induced recruitment of 2–8 follicles compared to a single follicle in control hens. In contrast to pre-recruitment follicles, incubated GC from eCG-recruited follicles had initiated differentiation, indicated by increased CYP11A1 and rhFSH-induced STAR mRNA and progesterone. Equine CG and rhFSH each increased the number of recruited follicles in a dose-dependent manner. Further, CYP11A1 mRNA was significantly increased in GC layers from recruited, compared to non-recruited, follicles. We conclude that FSH-responsiveness within the GC layer of each pre-recruitment follicle increases with follicle size, and propose that this establishes the order of daily follicle recruitment.",
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Response of hen pre-recruitment ovarian follicles to follicle stimulating hormone, in vivo. / Ghanem, Kahina; Johnson, Alan Leslie.

In: General and Comparative Endocrinology, Vol. 270, 01.01.2019, p. 41-47.

Research output: Contribution to journalArticle

TY - JOUR

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AU - Ghanem, Kahina

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N2 - In laying hens, pre-recruitment ovarian follicles (1–8 mm diameter) are arranged as a continuum of size and predicted maturity. Cyclic recruitment of a pre-recruitment follicle to the preovulatory stage begins, in part, by the ability of the granulosa cell (GC) layer to initiate responsiveness to follicle stimulating hormone- (FSH-) induced cyclic adenosine monophosphate. The objective of this study was to determine if increased circulating concentrations of FSH during the ovulatory cycle increase the number of recruited follicles, in a dose-dependent manner. Equine chorionic gonadotropin (eCG) was initially tested due to its FSH-like properties and long half-life. Laying hens were injected, i.m., with 0 or 100 IU eCG, and ovaries were collected 29 h later. Recruited follicles were initially identified based on incorporation of yellow yolk and a weight of 250–900 mg. Recruitment was subsequently confirmed by both incubating the GC layer for 3 h with recombinant human (rh) FSH to establish FSH-responsiveness and quantifying P450 side-chain cleavage enzyme (CYP11A1) mRNA. Additional hens were injected with 0, 30, 75, and 300 IU eCG to establish a dose–response. Because eCG exhibits some luteinizing hormone activity, FSH-induced recruitment was evaluated by injecting 0.1, 0.33, 0.66, 1 or 3.3 µg rhFSH. Ovaries were collected 29 h post-injection, and expression of CYP11A1 mRNA was quantitated in GCs from recruited and pre-recruitment follicles. One hundred IU eCG induced recruitment of 2–8 follicles compared to a single follicle in control hens. In contrast to pre-recruitment follicles, incubated GC from eCG-recruited follicles had initiated differentiation, indicated by increased CYP11A1 and rhFSH-induced STAR mRNA and progesterone. Equine CG and rhFSH each increased the number of recruited follicles in a dose-dependent manner. Further, CYP11A1 mRNA was significantly increased in GC layers from recruited, compared to non-recruited, follicles. We conclude that FSH-responsiveness within the GC layer of each pre-recruitment follicle increases with follicle size, and propose that this establishes the order of daily follicle recruitment.

AB - In laying hens, pre-recruitment ovarian follicles (1–8 mm diameter) are arranged as a continuum of size and predicted maturity. Cyclic recruitment of a pre-recruitment follicle to the preovulatory stage begins, in part, by the ability of the granulosa cell (GC) layer to initiate responsiveness to follicle stimulating hormone- (FSH-) induced cyclic adenosine monophosphate. The objective of this study was to determine if increased circulating concentrations of FSH during the ovulatory cycle increase the number of recruited follicles, in a dose-dependent manner. Equine chorionic gonadotropin (eCG) was initially tested due to its FSH-like properties and long half-life. Laying hens were injected, i.m., with 0 or 100 IU eCG, and ovaries were collected 29 h later. Recruited follicles were initially identified based on incorporation of yellow yolk and a weight of 250–900 mg. Recruitment was subsequently confirmed by both incubating the GC layer for 3 h with recombinant human (rh) FSH to establish FSH-responsiveness and quantifying P450 side-chain cleavage enzyme (CYP11A1) mRNA. Additional hens were injected with 0, 30, 75, and 300 IU eCG to establish a dose–response. Because eCG exhibits some luteinizing hormone activity, FSH-induced recruitment was evaluated by injecting 0.1, 0.33, 0.66, 1 or 3.3 µg rhFSH. Ovaries were collected 29 h post-injection, and expression of CYP11A1 mRNA was quantitated in GCs from recruited and pre-recruitment follicles. One hundred IU eCG induced recruitment of 2–8 follicles compared to a single follicle in control hens. In contrast to pre-recruitment follicles, incubated GC from eCG-recruited follicles had initiated differentiation, indicated by increased CYP11A1 and rhFSH-induced STAR mRNA and progesterone. Equine CG and rhFSH each increased the number of recruited follicles in a dose-dependent manner. Further, CYP11A1 mRNA was significantly increased in GC layers from recruited, compared to non-recruited, follicles. We conclude that FSH-responsiveness within the GC layer of each pre-recruitment follicle increases with follicle size, and propose that this establishes the order of daily follicle recruitment.

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