SEARCH · Search PubMed

Results for “Follicular development”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources

PubMed1979

Inhibitory effect of charcoal-treated porcine follicular fluid upon serum FSH levels and follicular development in the rhesus monkey.

Injection of charcoal treated porcine follicular fluid into 4 intact, 4 long term castrate and 2 postmenopausal rhesus monkeys brought about a selective decline in serum FSH levels. Luteinizing hormone levels were not significantly decreased. Intraperitoneal injection of 4 ml porcine follicular fluid every 8 hours for the first 4 days of the menstrual cycle led to a decrease in follicle and granulosa cell growth observed at that midcycle. Treatment with porcine serum did not exert this effect.

Animals↗

PubMed2001

C-cell and thyroid epithelial tumours and altered follicular development in transgenic mice expressing the long isoform of MEN 2A RET.

Gain-of-function mutations in the gene encoding the receptor tyrosine kinase RET have been identified as the aetiological factor for multiple endocrine neoplasia type 2A (MEN2A). MEN2A is a dominantly-inherited cancer predisposition syndrome characterized by medullary thyroid carcinoma, a tumour of the calcitonin-producing thyroid C-cells. There are three isoforms of RET: RET9, RET43 and RET51, and although in vitro evidence suggests they vary in cellular transformation activities, little is known about their function in tumorigenesis in vivo. To address this, we used RET51 cDNA to construct mice in which the most frequent MEN2A mutation, Cys-634-Arg, was expressed under the control of the human calcitonin promoter (CT-2A mice). These mice developed C-cell tumours resembling human MTC and follicular tumours resembling human papillary thyroid carcinoma (PTC) depending on the founder line examined. One founder line developed compound MTC/PTC at low frequency (8%) and pancreatic cystadenocarcinoma. CT-2A mice also displayed a developmental defect in thyroid follicular structure, in which much of the thyroid was occupied by large irregular cystic follicles thought to be derived from the ultimobranchial body, a developmental precursor of the thyroid gland. The CT-2A mice will provide a suitable model to further study the effects of the MEN 2A RET mutation in vivo.

Amino Acid Substitution↗

PubMed1996

Localization of laminin proteins during early follicular development in pig and rabbit ovaries.

Laminin, a major component of the basal lamina, is known to be important in the differentiation of epithelial cells. The outer granulosa cell layer of ovarian follicles is attached to a basal lamina surrounding the follicle and it has been demonstrated that proteins of the basal lamina can alter the steroidogenic capacity and cytoskeletal composition of mature granulosa cells. The present studies were carried out to evaluate the developmental expression of laminin proteins in the basal lamina of ovarian follicles during early stages of granulosa cell differentiation. Ovaries from sexually immature pigs (0-20 weeks of age) and rabbits (0-12 weeks of age) were used for this study because formation of primordial follicles and initiation of follicular growth occur partially or completely postnatally. Specific antibodies were made against laminin beta 1/gamma 1 chains using protein purified by high resolution two-dimensional polyacrylmide gel electrophoresis. These antibodies were used in immunohistochemical localization studies to demonstrate that laminin is associated with the basal lamina surrounding egg clusters and their connections to the ovarian surface epithelium and ovarian rete during early ovarian development. In addition, laminin was observed to associate with a continuous matrix that surrounds forming primordial follicles as they are isolated from the egg clusters. Laminin is localized in the basal lamina of primordial, primary, secondary, and tertiary follicles of both pig and rabbit ovaries. Laminin proteins are not only expressed throughout early follicular development in pigs and rabbits, but are also found surrounding the germ cell compartments prior to initiation of meiosis and formation of primordial follicles. These results demonstrate that laminin proteins are deposited in the basal lamina well before granulosa cells undergo morphological differentiation. This pattern of expression suggests that laminin proteins alone do not control changes in granulosa cell morphology during early development but may be required to maintain cell lineage commitment.

Animals↗

PubMed2005

Follicular fluid concentrations of free insulin-like growth factor (IGF)-I during follicular development in mares.

The objective of the present study was to evaluate changes in concentrations of free insulin-like growth factor (IGF)-I in follicular fluid (FFL) during follicle development in the mare. Mares (n = 14) were classified as either in the follicular phase (n = 8) or luteal phase (n = 6). Follicles (n = 92) were categorized as small (6-15 mm; n = 54), medium (16-25 mm; n = 23) or large (>25 mm; n = 15) and FFL was collected. Free IGF-I levels in FFL in large follicles of follicular phase mares were greater (P < 0.05) than in large follicles of luteal phase mares and small or medium follicles of luteal and follicular phase mares. Free IGF-I concentrations were greater (P < 0.05) in large follicles of luteal phase mares than small but not medium follicles of luteal phase mares. FFL ratio of estradiol:progesterone paralleled changes in free IGF-I. Free IGF-I concentrations were negatively correlated (P < 0.05) with insulin-like growth factor binding protein (IGFBP)-2, -4 and -5 but not IGFBP-3 levels. In addition, free IGF-I concentrations in FFL were positively correlated (P < 0.01) with FFL estradiol, progesterone, androstenedione, estradiol:progesterone ratio, total IGF-I and total IGF-II. We conclude that increases in intrafollicular levels of bioavailable (free) IGF-I are associated with increased steroidogenesis in developing mare follicles.

Androstenedione↗

PubMed2002

Pattern of follicular development in high fecundity Olkuska ewes during the estrous cycle.

Folliculogenesis was studied daily in the 18 oestrous cycles in six prolific Olkuska ewes from October to December using transrectal ultrasonography to record the number and size of all ovarian follicles > or =2 mm in diameter. Blood samples were taken once a day and were analyzed for concentrations of FSH, LH, estradiol and progesterone. Follicular and hormonal data were analyzed for associations between different stages of development of the follicular waves and concentrations of FSH and estradiol. The first wave during which at least one follicle reached maximum diameter of > or =4 mm after ovulation, was defined as a wave 1, and the following waves were numbered sequentially. Waves 1, 2, 3, 4 and the ovulatory one emerged on days: -2 to 4, 4 to 8, 6 to 11, 10 to 12 and 11 to 15, respectively. The mean number of follicles per wave that reached diameter of > or =4 mm was 4.15 +/- 1.1 and 16.62 +/- 8.6 follicles per estrous cycle of a total 299 follicles were observed. Significantly more follicles (p> or =0.05) emerged on days 2, 8 and 13 than in other days. Serum FSH concentrations fluctuated from 0.11 ngml(-1) on day 2 to preovulatory maximum 1.81 ngml(-1) on day 17 of the estrous cycle. The emergence of follicular waves was associated with elevations of FSH concentrations in blood serum. The mean increase in FSH concentration was followed by the recruitment of follicles of the next wave. The mean daily FSH concentration and the mean number of follicles emerging each day were negatively correlated. The length of the interwave interval (4.4 +/- 1.6 days) did not differ significantly from the interval between pulses of FSH (4.8 +/- 0.3 days). The mean serum estradiol concentrations showed fluctuations until day 14 and then gradually increased from 5.47 +/- 0.3 pgml(-1) to reach a peak 13.14 +/- 0.2 pgml(-1) on the day before ovulation. To summarize, the growth of ovarian follicles during the estrous cycle in high fecundity Olkuska sheep exhibited a distinct wave-like pattern. Ovarian follicles emerged from the pool of 2 mm follicles. The preovulatory follicles originated from the large follicle population were present in the ovary at the time of luteal regression. The initial stages of the growth of the largest follicles appears to be controlled primarily by increases in FSH secretion.

Animals↗

PubMed1979

Effects of gonadotropins on follicular development, ovulation, and atresia in the mature guinea pig.

The induction of follicular growth, ovulation, and atresia by heterologous gonadotropic preparations was studied late in the reproductive cycle of the adult female guinea pig. Human chorionic gonadotropin (HCG) administration (10 IU) 12 days following the first signs of opening of the vaginal membrane was found to stimulate ovulation within 24 h in all animals studied, as evidenced by recovery of ova from their oviducts as well as the presence of postovulatory follicles in their ovaries. Histologically, ovaries of animals receiving HCG exhibited atretic changes in most of the follicles smaller than 999 micrometer in diameter. Pregnant mares serum gonadotropin (PMSG, 10 IU) administered on days 9 and 10 of the cycle was not sufficient to stimulate ovulation in this species although histological changes in the follicular complement were observed. Administration of PMSG prior to the HCG appeared to have an inhibitory effect on ovulation induction. Follicles luteinizing with entrapped ova were seen in all groups receiving exogenous gonadotropin, although they were most prevalent in the animals receiving the maximum total gonadotropin doses (i.e. PMSG + HCG).

Animals↗

PubMed1997

Impact of different patterns of feed intake during lactation in the primiparous sow on follicular development and oocyte maturation.

The potential contribution of nutritionally induced differences in follicular and oocyte maturity to embryo survival was addressed in pigs. When primiparous, lactating sows are fed to appetite from farrowing to day 21 of lactation and then with feed intake restricted to 50% from day 22 to 28 (restricted), embryo survival is 64% at day 28 of gestation, compared with 85% in sows fed to 50% from farrowing to day 21 and then fed to appetite from day 22 to 28 (refed). In the present study, 32 sows were equally assigned to these two treatments (restricted or refed) but they were slaughtered 38 h before the estimated time of oestrus. The largest 15 follicles per sow were aspirated and follicular fluid recovered for analysis in vitro. Although plasma oestradiol concentration before slaughter and follicular fluid oestradiol concentration at slaughter were not different (P > 0.05), refed sows had more (P < 0.02) large follicles than did restricted sows. Cumulus expansion scores in vitro were not different between treatments, although more (P < 0.03) oocytes from refed sows had matured to metaphase II than those from restricted sows. Similarly, although cumulus expansion of oocyte-cumulus complexes from prepubertal gilts oocytes incubated with follicular fluid obtained from restricted (n = 1227) or refed (n = 1147) sows was not different (P > 0.05), the rate of oocyte nuclear maturation was greater (P < 0.012) after incubation with follicular fluid from refed than with that from restricted sows. Differences in the maturation of the follicle and oocyte in the period before the LH surge may therefore contribute to the treatment effects on embryo survival.

Animals↗

PubMed1999

[Induced ovarian follicular development: theoretical basis and therapeutic applications].

The fine mechanisms involved in human follicular growth in the ovary are not completely elucidated yet. The morphometric parameters are, by far, better understood than the metabolic ones. However, new data on the steroidogenic follicular human activity and their ability to respond to endogenous and exogenous gonadotropins lead to a better understanding of the results of our different therapeutic schemes. On the other hand, the selection criteria of patients have been modified, dealing now with the ovarian age much more than the real age. A precise determination of the ovarian age allows us to better drive our stimulation protocols and helps us to switch to other alternatives rather than multiplying useless and ineffective stimulations. This is of major importance in term of psychological aspects as well as in term of public health costs for the society.

Adult↗

PubMed1997

[The role of growth factors during follicular development and maturation in the mammal ovary].

The progress of growth and follicular maturation require the participation of several modulators of growth, like gonadotropins, hormonal steroids, interleucins and growth factors, in this case, we are working with the aspects related with mitosis and the differentiation of the cellular components of the follicle, by means of autocrins and/or paracrins action. Sinergical action of growth, factors (EGF, TGF alpha, TGF beta, FGFs and IGFs) stimulating mitosis, is given by one mechanism of mutual reinforcing of its activities, besides of their interaction with gonadotropins and hormonal steroids favoring the proliferation and cytodifferentiation of follicle by stimulation of production and activation of steriodogenesis enzymes and the use of cholesterol coming from high and low density lipoprotein (LDL and HDL), controlling in this way the disponible cholesterol, that is the common substrate for steroids hormonal produced by teca and granulosa cells during the follicular maturation.

Animals↗

PubMed2003

Expression of wilms' tumor gene and protein localization during ovarian formation and follicular development in sheep.

Wilms' tumor protein (WT1) is a transcriptional repressor essential for the development of mammalian kidneys and gonads. To gain insight into possible roles of WT1 in ovarian formation and follicular function, we studied patterns of mRNA and protein localization throughout fetal gonadal development and in ovaries of 4-wk-old and adult sheep. At Day 24 after conception, strong expression of WT1 mRNA and protein was observed in the coelomic epithelial region of the mesonephros where the gonad was forming. By Day 30, expression was observed in the surface epithelium and in many mesenchymal and endothelial cells of the gonad. Epithelial cells continued to express WT1 throughout gonadal development, as did pregranulosa cells during the process of follicular formation. However, WT1 expression was not observed in germ cells. During follicular growth, granulosa cells expressed WT1 from the type 1 (primordial) to the type 4 stages, but thereafter expression was reduced in type 5 (antral) follicles, consistent with the differentiation of granulosa cells into steroid-producing cells. The possible progenitor cells for the theca interna (i.e., the cell streams in the ovarian interstitium) expressed WT1 heterogeneously. However, differentiated theca cells in antral follicles did not express WT1. Strong expression of WT1 was observed during gonadal development, which is consistent with a role for WT1 in ovarian and follicular formation in the ewe. WT1 was identified in many cells of the neonatal and adult ovaries, including granulosa cells, suggesting that this factor is important for preantral follicular growth. However, the decline in WT1 expression in antral follicles suggests that WT1 may prevent premature differentiation of somatic cells of the follicle during early follicular growth.

Animals↗

PubMed1991

Effects of exogenous insulin and body condition on metabolic hormones and gonadotropin-induced follicular development in prepuberal gilts.

To determine influences of insulin and body condition on follicular growth, prepuberal gilts (n = 16) treated with pregnant mare's serum gonadotropin (PMSG) were used in a 2 X 2 factorial experiment with main effects of insulin (0 or .4 IU/kg every 12 h beginning at 1800 on the day before PMSG) and backfat depth (moderate, 25 +/- .8; high, 32 +/- .7 mm; P less than .0001). Body weights were similar. Blood sampling was at 6-h intervals for analyses of LH, FSH, growth hormone (GH), glucagon, cortisol, insulin, insulin-like growth factor-I (IGF-I), plasma urea nitrogen (PUN), nonesterified fatty acids (NEFA), testosterone, estradiol-17 beta, and progesterone. Ovaries were removed 75 h after PMSG treatment, and visible small (less than or equal to 3 mm), medium (4 to 6 mm), large (greater than or equal to 7 mm), and macroscopically atretic follicles were counted. Administration of insulin increased IGF-I in fluid of medium follicles (108.8 vs 60.7 ng/ml; SEM = 13.3; P less than .05). Neither insulin nor fatness affected hCG binding by granulosa cells (12.5 +/- 1.6 ng/10(6) cells) or numbers of large (16.7 +/- 2.6) and medium (10.4 +/- 2.3) follicles. However, insulin increased the number of small follicles (58.9 vs 29.9; SEM = 9.7; P less than .05) and reduced the number of atretic follicles (3.8 vs 11.3; SEM = 1.1; P less than .05). The predominant effect of insulin on reducing number of atretic follicles was in the small size class (.6 vs 6.9; SEM = .6, P less than .01). Follicular fluid estradiol and progesterone were not affected by treatments; however, testosterone concentrations in large follicles were lower in gilts with higher backfat (32.5 vs 59.9 ng/ml; SEM = 4.0; P less than .05). Systemic LH, FSH, glucagon, cortisol, PUN, NEFA, estradiol, and testosterone were not affected by insulin or level of feeding. However, GH was lower in gilts that had higher backfat (overall average of 3.2 vs 2.8 ng/ml; SEM = .1; P less than .05). Insulin reduced atresia and altered intrafollicular IGF-I independently of body condition and without sustained effects on other hormones.

Animals↗

PubMed1994

Follicular development and embryo recovery following 3 versus 8 FSH injections in heifers.

Ovarian follicular dynamics and embryo yield were studied during 2 different FSH regimens for superovulation of cattle. Twenty heifers were given intramuscular injections of FSH (total of 35 mg NIH) either once daily for 3 days (Group 3x1) or twice daily for 4 days (Group 4x2). At 72 h after the first FSH injection, each animal was injected with 0.75 mg cloprostenol. Inseminations were performed at 12 h and 24 h after the onset of heat. Transrectal ultrasonography was performed on the day of the first FSH injection, the day of cloprostenol injection, the day of insemination and finally on the day of embryo recovery (day 6 or 7 after heat). The numbers of small (2-4 mm), medium (5-9 mm) and large (> 10 mm) size follicles were recorded. The total number of corpora lutea, eggs and transferable embryos were recorded on the day of embryo recovery. No differences were found between the 2 groups in either of the parameters studied (p > 0.05). It can be concluded that treatment with this FSH preparation once daily for 3 days gives a folliculogenic and superovulatory response similar to a treatment regimen where it is given twice daily for 4 days.

Animals↗

PubMed1997

Effect of dietary energy restriction on follicular development and luteal function in nonlactating beef cows.

Twenty nonlactating beef cows were used to determine the effects of dietary energy restriction on ovarian follicular and corpus luteum (CL) development. Cows were fed to either gain (controls) or lose (restricted; RES) body weight. Observations continued until RES cows developed a subfunctional CL (progesterone [P4] < 1.5 ng/mL on d 10 of a cycle; n = 4) or had functional CL (P4 > or = 1.5 ng/mL on d 10 of a cycle; n = 6) followed by anestrus, at which time observations were discontinued on individual controls. Estrous cycles were then standardized for all cows. For RES cows developing subfunctional CL, cycle A was the cycle before development of the subfunctional CL, and cycle B was the 11-d period during development of a subfunctional CL. For RES cows with a functional CL, cycle A was the next to last cycle before anestrus, and cycle B was the 11-d period during formation of a functional CL. Daily P4 concentrations did not differ (P > .10) between controls or RES cows developing functional CL during cycle B but were lower (P < .05) in RES cows developing subfunctional CL. Ovulatory follicles and CL were smaller (P < .05) in RES cows during cycles A and B compared with controls. Daily IGF-l concentrations were higher on d 2 through 4 of both cycles in RES cows developing functional CL compared with RES cows developing subfunctional CL (P < .05). Feeding diets limited in energy resulted in two types of CL. These differences may have been due to IGF-I concentrations.

3-Hydroxysteroid Dehydrogenases↗

PubMed1995

Changes in localization of ovarian immunoreactive estrogen receptor during follicular development in hens.

The aim of this study was to examine the changes of ovarian estrogen receptor (ER) localization in hens to determine the significance of estrogen-ER interactions for the regulation of follicular functions during their development. The ER was localized by immunocytochemistry in the various developmental and regressing stages of follicles, namely cortical and white follicles, the largest (F1, matured follicle) and third largest preovulatory follicles (F3, rapid growth phase follicle), and post-ovulatory follicles (POF). No immunoreaction for ER was observed in the cortical follicles, whereas the interstitial cells in the outer theca externa were ER positive in white follicles. The islets of epithelial cells (identical to estrogen producing cells) in the outer theca externa and granulosa cells were ER positive in F3 follicles. These ER immunoreactions observed in F3 follicle were remarkably reduced in F1 and POF. These results suggest that estrogen-ER interactions may be responsible for the follicular growth, and the loss of ER may be involved in the mechanism of follicular maturation. The estrogen-ER interactions may be also involved in the local control of the steroid production in follicles.

Animals↗

PubMed1979

Suppression of pituitary secretion of follicle-stimulating hormone by porcine follicular fluid during pro-oestrus and oestrus in the rat: effects on gonadotrophin and steroid secretion, follicular development and ovulation during the following cycle.

In this study, we have examined whether the suppression of raised plasma FSH concentrations at pro-oestrus and/or oestrus by porcine follicular fluid (PFF) affected the development of follicles for ovulation in the next cycle. Adult, 4-day-cyclic rats were injected with PFF or pig serum at various hours of pro-oestrus and oestrus. Plasma FSH levels were suppressed following PFF treatment at any time of pro-oestrus and oestrus. Furthermore, this suppression was always followed by a 'rebound' increase in plasma FSH. In contrast, plasma LH concentrations were unaffected by PFF treatment and neither gonadotrophin was altered by treatment with pig serum. When rats treated with PFF or pig serum were allowed to complete one additional cycle, plasma LH and FSH concentrations at the pro-oestrus and oestrus after treatment were not significantly different among groups regardless of treatment or time of treatment. All ovaries of rats treated with PFF or pig serum on the next pro-oestrus morning before ovulation were histologically similar. Furthermore, all animals ovulated a normal complement of ova at the next oestrus regardless of whether preovulatory, secondary or both increases of plasma FSH had been blocked by PFF treatment during the previous cycle. However, animals given PFF during the preceding cycle, plasma oestradiol and progesterone concentrations were significantly altered on the morning and afternoon of pro-oestrus respectively. These results suggest that increased plasma FSH concentrations at pro-oestrus and oestrus may not be essential for folliculogenesis and ovulation in the subsequent cycle. Alternatively, the 'rebound' of FSH on day 1 of dioestrus after the suppression of both phases of FSH secretion at pro-oestrus and oestrus may be sufficient to provide ovulatory follicles for the next pro-oestrous day.

Animals↗

PubMed1993

Effect of administration of porcine follicular fluid to gilts during the luteal phase of the estrous cycle on plasma gonadotropins, follicular development, and ovulation rate.

Eighty gilts were assigned randomly to receive twice daily i.v. injections of either 5 mL of steroid-reduced porcine follicular fluid (pFF) or .15 M saline (S) to evaluate the effects of suppression of FSH before, during, and 1 d after induced luteolysis on d 13 (d 0 = onset of estrus) on development of medium and large follicles during the follicular phase and subsequent ovulation rate. Ovaries were recovered and assessed for numbers of corpora albicantia (CA) and medium (NMF, 3 to 6.9 mm) and large (NLF, > 6.9 mm) follicles on d 13, 15, and 17 of the estrous cycle and number of corpora lutea (CL) in the group assigned to be examined after ovulation. Gilts assigned to the postovulatory group were bled at 12-h intervals from d 9.5 through 17. Administration of pFF suppressed concentrations of FSH during treatment with pFF (pFF, .38 +/- .02 vs S, .52 +/- .02 ng/mL, P < .05) and reduced NMF on d 13 (pFF, 17.3 +/- 4.0 vs S, 45.8 +/- 4.0, P < .01) and d 15 (28.1 +/- 4.0 vs 38.7 +/- 4.2, P < .05). The NMF declined markedly between d 15 and 17 in control gilts but not in pFF-treated gilts; pFF and S gilts had achieved similar NMF on d 17 (pFF, 23.1 +/- 4.0 vs S, 21.3 +/- 4.2). Large follicles were first observed on d 17 and were reduced substantially by prior treatment with pFF (pFF, 6.7 +/- 1.4 vs S, 12.4 +/- 1.5, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Gamete intrafallopian transfer (GIFT): use of minilaparotomy and an individualized regimen of induction of follicular development.

The performance of the gamete intrafallopian transfer (GIFT) technique, utilizing an individualized regimen of follicular induction and minilaparotomy in 45 patients with infertility of varying etiologies is reported. The induction regimen consisted of the administration of clomiphene citrate, 100 mg, from day 3 to day 7, and 150 IU FSH/LH (human menopausal gonadotropin [hMG]) from day 6 on. Human chorionic gonadotropin (hCG; 10,000 IU) was administered when at least two follicles measured 16 mm or more in diameter and when serum estradiol (E2) measurement revealed levels of 350 pg/ml per each main follicle. Up to two oocytes and 100,000 motile sperm were transferred to the fallopian tubes via the fimbria, using a catheter. Of the 45 cases, 13 became pregnant by clinical criteria (29 per cent). Of these 13 pregnancies, nine continued to term (69 per cent), three miscarried spontaneously (12 per cent) and one was an ectopic (7 per cent). Of the nine pregnancies that continued to term, five (55 per cent) were twins. Details of the GIFT procedure as well the preliminary non-human primate research studies that led to the development of the GIFT technique are discussed. It is concluded that GIFT is an excellent alternative to in vitro fertilization and embryo transfer (IVF; ET) in all cases of infertility that failed to conceive using conventional forms of therapy and in which the female partner presents at least one normal fallopian tube.

Animals↗

PubMed2004

Expression of mRNA of lipoprotein receptor related protein 8, low density lipoprotein receptor, and very low density lipoprotein receptor in bovine ovarian cells during follicular development and corpus luteum formation and regression.

Lipoproteins in the plasma are the major source of cholesterol obtained by the ovarian theca and granulosa cells for steroidogenesis. In this study, we have identified mRNA expression in bovine theca and granulosa cells of two lipoprotein receptors, low density lipoprotein receptor (LDLr) and very low density lipoprotein receptor (VLDLr) in granulosa cells from small antral follicles through preovulatory follicles and in theca cells from large and medium sized antral follicles. In the corpus luteum (CL) both these receptors were found in the developing and differentiating stages whereas only mRNA for VLDLr was detected in the regression stage. This study also described for the first time, the presence of lipoprotein receptor related protein (LRP8) in granulosa cells from small antral follicles through preovulatory follicles and in theca cells from large and medium sized antral follicles. This may indicate a role of LRP8 in cholesterol delivery to steriodogenic cells. LRP8 was not detected in any of the CL stages. The roles of the LDLr superfamily in lipid transport to ovarian cells and its participation in follicular and CL development and regression is discussed.

Animals↗