Increased oocyte degeneration and follicular atresia during the estrous cycle in anti-Müllerian hormone null mice.
Anti-Müllerian hormone (AMH) plays an important role in folliculogenesis. AMH null mice display an increased recruitment of primordial follicles. Nevertheless, these mice do not have proportionally more preovulatory follicles. Therefore, AMH null mice provide an interesting genetic model to study the regulation of species-specific number of preovulatory follicles. We studied the follicle pool throughout the estrous cycle at 4 months of age. Analysis of the follicle pool revealed that AMH null mice have an increased and earlier cyclic recruitment of growing follicles despite a blunted FSH surge at estrus. However, FSH levels at estrus were apparently too low to support growth to the preovulatory stage because an increased level of atresia was observed, which neutralized the increased cyclic recruitment. When AMH null mice were subjected to a superovulation scheme, the rise in FSH levels resulted in the rescue of the recruited cohort of growing follicles. Analysis of the follicle pool also revealed that the increased recruitment of primordial follicles in AMH null mice was neutralized by an increased loss of follicles during the transition from small preantral to large preantral follicle. This major loss of follicles was not completely reflected by a corresponding augmentation of atresia but did correspond with an increased number of oocyte remnants observed in AMH null mice. We conclude that a combination of increased oocyte degeneration and increased follicular atresia neutralizes the increased initial and cyclic recruitment in AMH null mice to a normal number of preovulatory follicles.
Visser
Jenny A
JA
Department of Internal Medicine, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands. j.visser@erasmusmc.nl
Durlinger
Alexandra L L
AL
Peters
Isolde J J
IJ
van den Heuvel
Edwin R
ER
Rose
Ursula M
UM
Kramer
Piet
P
de Jong
Frank H
FH
Themmen
Axel P N
AP
D000818:Animals; D054304:Anti-Mullerian Hormone; D003338:Corpus Luteum / Q000166:cytology / Q000502:physiology; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000097:blood; D005496:Follicular Atresia / Q000502:physiology*; D005498:Follicular Phase / Q000502:physiology*; D006023:Glycoproteins / Q000097:blood / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009865:Oocytes / Q000166:cytology* / Q000502:physiology; D009929:Organ Size; D006080:Ovarian Follicle / Q000166:cytology / Q000502:physiology; D013480:Superovulation / Q000502:physiology; D013735:Testicular Hormones / Q000097:blood / Q000235:genetics*; D014599:Uterus / Q000033:anatomy & histology
D006023:Glycoproteins; D013735:Testicular Hormones; D054304:Anti-Mullerian Hormone; D005640:Follicle Stimulating Hormone