An autoradiographic study of follicle growth in the ovaries of cyclic rats

Groen-Klevant, A. C.

doi:10.1530/acta.0.0960377

Cited by 4 publications

(4 citation statements)

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“…Otherwise, a slight increase in the number of Md follicles (1.5-fold) and a more relevant increase in the number of follicles > class 1 (threefold) was found at 07:00 h on oestrus. These results are in agreement with previous morphometric (Hirshfield and Midgley, 1978a;Butcher and Kirkpatrick-Keller, 1984;van Cappellen et al, 1993) and autoradiographic (Groen-Kevlant, 1981) studies reporting that the number of small follicles did not show marked changes during the cycle and that follicles from 260 to 390 pm in diameter (corresponding to large Md and classes 1-2 in this study) are recruited between pro-oestrus and oestrus. Since follicles larger than 200 pm in diameter repre¬ sented a small proportion of the total number of follicles per ovary, the increase in the number of these follicles could be due to small changes in the relative numbers of Ma-Mc follicles, which represented more than 80% of the total number of follicles.…”

Section: Discussionsupporting

confidence: 94%

Follicular growth pattern in cyclic rats from late pro-oestrus to early oestrus

Gaytán

Bellido²,

Morales³

et al. 1997

Reproduction

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Adult cyclic rats were studied from 16:00 h on pro-oestrus to 07:00 h on oestrus to relate the cyclic hormonal changes to the proliferative activity and growth pattern of growing follicles. The proliferative activity was studied by 5-bromodeoxyuridine (BrdU) labelling and by the presence of mitoses. Small growing follicles (less than 275 microns in diameter) were divided into five classes: multilaminar classes a (Ma, up to 75 microns in diameter), b (Mb, 76-150 microns), c (Mc, 151-200 microns) and d (Md, 201-274 microns) and follicles measuring > or = 275 microns in diameter were considered as > or = class 1, following previous classifications. I.H concentrations were maximal at 18:30 h on pro-oestrus, and this was coincident with an increase in FSH, prolactin and progesterone concentrations, whereas oestradiol and testosterone concentrations were decreased. From 02:00 h on oestrus the concentrations of all hormones, except those of FSH, were decreased. The number of Ma, Mb and Mc follicles did not change during pro-oestrus-oestrus, whereas an increase in the number of follicles > or = class 1 was found at 07:00 h on oestrus. This appears to be a consequence of the increased proliferative activity of Md follicles, evidenced by the increase in the BrdU labelling and mitotic index of this follicle class, found from 02:00 to 07:00 h on oestrus, together with a decrease in the percentage of early atretic follicles > or = class 1 at 07:00 h on oestrus. This study provides an improved classification of small growing follicles into discrete classes and delineates a size class of follicles (Md follicles) that is responsive to the cyclic hormonal changes on early oestrus.

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Section: Discussionsupporting

confidence: 94%

Follicular growth pattern in cyclic rats from late pro-oestrus to early oestrus

Gaytán

Bellido²,

Morales³

et al. 1997

Reproduction

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“…Further, autoradio graphic studies in the mouse [Pedersen. 1970] and rat [Groen-Klevant. 1981], confirm the duration of DNA syn thesis to be shorter for all primary and secondary follicles at estrus.…”

Section: Discussionmentioning

confidence: 99%

Morphometric Study of Ovarian Follicular Growth during the Estrous Cycle of the Laboratory-Maintained Indian Desert Gerbil, <i>Meriones hurrianae</i> (Jerdon)

Saidapur

Kamath²

1993

Cells Tissues Organs

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The pattern of changes in the population of healthy and regressing follicles in relation to the estrous cycle, was studied in the recently domesticated desert gerbil, Meriones hurrianae, which exhibits a longer cycle (proestrus: 1.5 days; estrus: 1 day; metestrus: 1.5 days; diestrus: 3 days). As the granulosa cell layers were not distinct, the follicles were classified on the basis of their morphology and size (group I: small preantral follicles; group II: large preantral follicles; group III: small antral follicles; group IV: medium-sized antral follicles; group V: large-sized follicles; group VI: Graafian follicles). Regressing follicles were classified likewise. Five animals were used for each stage of the cycle. One ovary from each gerbil was serially cut and stained with hematoxylin-eosin. Healthy and regressing follicles were found throughout the cycle. The follicular development occurred typically in a biphasic manner. In phase A, in which follicles reach the antral stage, the growth of oocytes and follicles is linearly correlated, whereas, in phase B, oocyte size remains stationary while follicle size increases due to accumulation of antral fluid. However, oocyte growth and nucleus growth are positively and linearly correlated (r = 0.74). The healthy follicles under 260 μm (groups I, II) do not fluctuate in the ovary of cyclic gerbils, whereas follicles in group III (261–350 μm) increase significantly (p < 0.05) at estrus and those of group IV in diestrus. Further, healthy group III follicles are reduced in diestrus while regressing follicles in group III increase. These findings thus suggest that the antral follicles are rescued from atresia at estrus. Further selection of follicles for growth and ovulation, or their exit through atresia occurs in diestrus. The gerbil produces 3 ova per ovary during each cycle, and the growth of selected follicles is completed in two cycles (14–15 days). Atresia in preantral follicles is characterized by the degeneration of oocytes followed by the granulosa cells, whereas initiation of atresia among antral follicles is due to pyknosis of the granulosa followed by the degeneration of oocytes. Occasionally, pseudomaturation divisions occur in regressing follicles prior to oocyte fragmentation. In addition to the commonly occurring types of atresia in the gerbil, occasionally intraovarian release of oocytes from the regressing follicles is encountered.

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“…These changes include a persistent rather than cyclic oestrus. During persistent oestrus, circulating oestradiol is present from many large ovarian follicles, but the luteinizing hormone surge mechanism is inhibited and ovulation does not occur (Leung, 1978;Pantic and Lovren, 1981).Studies on abnormalities of the reproductive tract indicate that oestrogens have inhibitory effects on ovarian steroidogenesis (Groen-Clevant, 1981;Wada et al, 1984). The uterus and vagina are also dependent on the effect of hormones administered to neonates (Ennis and Davies, 1982;Keys and King, 1989).…”

mentioning

confidence: 99%

“…Studies on abnormalities of the reproductive tract indicate that oestrogens have inhibitory effects on ovarian steroidogenesis (Groen-Clevant, 1981;Wada et al, 1984). The uterus and vagina are also dependent on the effect of hormones administered to neonates (Ennis and Davies, 1982;Keys and King, 1989).…”

mentioning

confidence: 99%

EFFECT OF NEONATAL OESTROGEN AND hCG TREATMENT ON THE GENITAL ORGANS OF ADULT FEMALE RATS

Nikolić

Mrvić

Ivanov

et al. 1999

Acta Veterinaria Hungarica

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The ovaries and the uterine as well as vaginal mucous membranes of 80-, 180-and 365-day-old intact female rats and females neonatally treated with a single dose of oestrogen and repeated doses of human chorionic gonadotropin (D+/ were studied. Numerous follicles, interstitial cells and corpora lutea (CL) were Key words: Rat, ovary, uterus, vagina, oestrogen, hCG The progressive decline of regular oestrous cycles and ovulatory functions with advancing age in female rats has been well documented in previous studies (Pantic and Lovren, 1981;Ennis and Davies, 1982;Nass et al., 1984). In female rats and mice, neonatal oestrogen treatment induces changes in the reproductive tract that may persist throughout the animals life (Pantic, 1981). These changes include a persistent rather than cyclic oestrus. During persistent oestrus, circulating oestradiol is present from many large ovarian follicles, but the luteinizing hormone surge mechanism is inhibited and ovulation does not occur (Leung, 1978;Pantic and Lovren, 1981).Studies on abnormalities of the reproductive tract indicate that oestrogens have inhibitory effects on ovarian steroidogenesis (Groen-Clevant, 1981;Wada et al., 1984). The uterus and vagina are also dependent on the effect of hormones administered to neonates (Ennis and Davies, 1982;Keys and King, 1989).In this paper, attention is focused on the ovarian follicles and interstitial tissue and on the properties of uterus and vagina in adult rats neonatally treated with oestrogen and human chorionic gonadotropin (hCG).

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An autoradiographic study of follicle growth in the ovaries of cyclic rats

Cited by 4 publications

References 9 publications

Follicular growth pattern in cyclic rats from late pro-oestrus to early oestrus

Follicular growth pattern in cyclic rats from late pro-oestrus to early oestrus

Morphometric Study of Ovarian Follicular Growth during the Estrous Cycle of the Laboratory-Maintained Indian Desert Gerbil, <i>Meriones hurrianae</i> (Jerdon)

EFFECT OF NEONATAL OESTROGEN AND hCG TREATMENT ON THE GENITAL ORGANS OF ADULT FEMALE RATS

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