Biomedical subjects

H D Guthrie

Publications and source records attributed to H D Guthrie.

At least 37 records · Page 2Linked to original sources

PubMed1996

Expression of androgen receptors and steroidogenic enzymes in relation to follicular growth and atresia following ovulation in pigs.

Among the new antral follicles that develop after ovulation in pigs, the incidence of atresia, based on granulosa cell apoptosis, increases between Days 5 and 7 of the estrous cycle. The purpose of this study was to determine how follicular growth and atresia affected the expression of some key enzymes regulating follicular steroidogenesis and androgen receptor on Days 3, 5, and 7 after the onset of estrus. Ovaries were frozen in liquid propane for subsequent sectioning and immunohistochemical analysis. Ninety-six follicles were classified according to size as small (< 3 mm), medium (3-5 mm), or large (> 5 mm). Follicles in the active stages of the cell cycle were identified by the presence of the cell proliferation-associated nuclear antigen Ki-67 in granulosa cells. Follicles with apoptotic cells were identified by in situ 3'-end labeling of DNA. Staining intensity of antigens on sections was assigned a numeric value (0-3). Follicles assigned a value > 1 for 3'-end labeling in their granulosa cells were classified atretic. The percentage of atretic follicles increased (p < or = 0.05) from 5% on Days 3 and 5 to 41% on Day 7. Expression of Ki-67 in granulosa cells was more strongly (p < or = 0.05) associated with nonatretic follicles (98% expressing) than with atretic follicles (41% expressing). Aromatase cytochrome P450 (P450arom) was localized predominantly in granulosa cells of nonatretic follicles and was undetectable in atretic follicles. Androgen receptor in granulosa cells and expression of P450 17 alpha-hydroxylase/C17-20 lyase (P450c17) in theca interna were lower (p < or = 0.001) in atretic follicles than in nonatretic follicles. The expression of 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) was localized to the theca interna and was unaffected by follicle atresia. In nonatretic small follicles, the expression of P450arom and P450c17 decreased (p < 0.01) between Days 3 and 7 while expression of Ki-67 was unchanged. In nonatretic follicles, increased follicle size was associated with a decrease (p < 0.01) in androgen receptor expression and increases (p < 0.01) in P450arom, P450c17, and 3 beta HSD expression. In conclusion, increased expression of steroidogenic enzymes was associated with follicular growth. Loss of P450arom expression in vivo is an early event in atresia and is followed by decreased cell proliferation, and decreased expression of androgen receptor and P450c17.

3-Hydroxysteroid Dehydrogenases↗

PubMed1995

Expression of cytochrome P450 1A1, an estrogen hydroxylase, in ovarian granulosa cells is developmentally regulated.

In this paper we report the analysis of porcine ovarian granulosa cells for the expression of several known hepatic estrogen hydroxylase RNAs. Of the P450s examined, only CYP 1A1 RNA was detected. Accordingly, the regulation of this mRNA was studied. The RNA for CYP 1A1 was dramatically and completely induced within 2 hours after exposure of immortalized granulosa cells to 3-methyl-cholanthrene (3MC) and expression could be inhibited with 10 microM phorbol myristate acetate. This message was also inducible by 3MC in cultured primary granulosa cells isolated from immature and developing follicles. Dexamethasone increased the relative expression of CYP 1A1 RNA in 3MC treated cells. In the absence of 3MC, the CYP 1A1 message was expressed in cultured granulosa cells from developing but not immature follicles, indicating developmental regulation of this enzyme. Further support for developmental regulation was provided by studies which detected the appearance of CYP 1A1 RNA during growth of ovarian follicles in vivo. This is the first report identifying a specific P450 estrogen hydroxylase RNA in ovarian granulosa cells.

Animals↗

PubMed1995

Atresia in follicles grown after ovulation in the pig: measurement of increased apoptosis in granulosa cells and reduced follicular fluid estradiol-17 beta.

The incidence of atresia in the first group of follicles grown after ovulation was investigated in the pig. At slaughter, 113 follicles 3-6 mm in diameter were dissected from the ovaries of four pregnant pigs per day on Days 5, 6, and 7 after the onset of estrus. Granulosa cells were isolated from each follicle. The percentage of granulosa cells containing sub-diploid amounts of DNA (%Ao cells), a measure of apoptosis, was determined for each follicle by DNA fluorescence flow cytometry of propidium iodide (PI) stained nuclei of ethanol-fixed cells. Granulosa cell DNA condition was used to classify follicles. Follicles with > or = 10% Ao cells (n = 33) were designated biochemically atretic (BA), and follicles with < 10% Ao cells (n = 80) were designated biochemically healthy (BH). Internucleosomal cleavage, also indicative of apoptosis, was determined by autoradiographic analysis of [32P]-3'-end-labeled DNA from granulosa cells. Densitometric analysis showed that optical density of [32P]-3'-end-labeled DNA fragments in the 0.18-20-kb size range was correlated with the %Ao cells (R > or = 0.90, N = 22, p < 0.001). The incidence of pigs with BA follicles was 2 of 4, 3 of 4, and 4 of 4 on Days 5, 6, and 7, respectively. The %BA follicles per pig (mean +/- SEM) increased (p < or = 0.01) between Days 5 and 7; values were 6.2 +/- 3.6, 28.1 +/- 13.5, and 50.0 +/- 7.1, respectively, on Days 5, 6, and 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Changes in insulin-like growth factor-binding protein-2 and -3 in follicular fluid during atresia of follicles grown after ovulation in pigs.

In pigs, medium-sized follicles (3-6 mm in diameter), lost during preovulatory maturation, are rapidly replenished after ovulation, increasing tenfold in number between day 3 and day 8 of the oestrous cycle. The incidence of atresia in medium-sized follicles was previously found to increase between day 5 and day 7 after the onset of oestrus (day 0). This study was conducted to determine whether changes in concentrations of insulin-like growth factor binding proteins (IGFBPs) in pig follicular fluid from medium-sized follicles were related to increased incidence of atresia. Individual follicles were isolated on days 5, 6 and 7 after oestrus from eleven pigs. Follicles were defined as atretic when they contained > or = 10% apoptotic granulosa cells (cells containing subdiploid amounts of DNA fluorescence determined by flow cytometry). Concentrations of IGFBP-2 and -3 were determined by ligand blot analysis with 125I-labelled insulin-like growth factor II and quantified by densitometry. The mean percentage of apoptotic cells per follicle increased (P < or = 0.01) from 3.6 to 35.0 and the mean concentration of IGFBP-2 increased (P < or = 0.001) 3.3-fold between day 5 and day 7 after oestrus. The concentration of IGFBP-3 did not differ significantly among days. Mean oestradiol concentration in follicular fluid decreased (P < or = 0.05) from 52.3 to 0.9 ng ml-1 between day 5 and day 7. Androstenedione concentrations in follicular fluid also decreased (P < or = 0.01) between day 5 and day 7, but progesterone did not differ significantly among days.(ABSTRACT TRUNCATED AT 250 WORDS)

Androstenedione↗

PubMed1995

Follicular atresia in pigs: measurement and physiology.

The physiological regulation of follicular atresia was investigated during the early luteal phase after ovulation and during altrenogest-synchronized preovulatory maturation in pigs (gilts). Apoptosis in dispersed granulosa cells was determined by flow cytometry. Apoptotic (A0) cells contain low, subdiploid amounts of DNA fluorescence. Follicles were classified biochemically as atretic or nonatretic based on the percentage of A0 (% A0) cells, atretic with > or = 10%, and nonatretic with < 10% A0 granulosa cells. The % A0 granulosa cells/follicle ranged from .02 to 89. Follicles containing debris in their isolated granulosa cells were classified as morphologically atretic. The morphological and biochemical criteria of atresia were in agreement for 224 of 248 follicles. Internucleosomal DNA cleavage, the hallmark of apoptosis, was determined by autoradiographic analysis of [32P]3'-end labeled DNA from granulosa cells. Densitometric analysis showed that optical density of [32P]3'-end labeled DNA fragments in the .18 to 20 kbp size range was correlated with the % A0 cells (R > .9, n = 22, P < .001). During altrenogest-synchronized preovulatory maturation, < 5% of large (> 6 mm in diameter) follicles were atretic. Among medium-sized follicles (3 to 6 mm) on d 1 and 3 of preovulatory maturation, only 17% were atretic, in contrast with d 5 when 87% were atretic. During the early luteal phase, atretic follicles/pig increased from 6% on d 5 to 50% on d 7 after estrus. Follicular fluid estradiol-17 beta concentration was greater (P < .001) in nonatretic than in atretic follicles on d 5 and 6 after estrus, but by d 7 estradiol-17 beta had decreased to a mean < 1 ng/mL in nonatretic and atretic follicles. The increase in apoptosis in granulosa cells and loss of estradiol-17 beta production in vivo indicated a high incidence of atresia among the first group of follicles grown after ovulation in pigs. These results indicate that apoptotic cell death was involved in degeneration of granulosa cells and atresia during two different stages of follicular development.

Animals↗

PubMed1994

Flow cytometric determination of degraded deoxyribonucleic acid in granulosa cells to identify atretic follicles during preovulatory maturation in the pig.

Granulosa cells of individual follicles were analyzed by DNA fluorescence flow cytometry to determine how the percentage of cells with degraded DNA and the distribution of cells in the phases of the cell cycle (Go/G1, S1, G2/M) related to the incidence of morphological atresia and to changes in follicular steroid concentrations. Follicles were dissected from ovaries recovered at slaughter on Days 1, 3, 5, or 7 of altrenogest-synchronized preovulatory maturation. Twenty-one follicles with debris among their isolated granulosa cells were classified as morphologically atretic (MA); 92 follicles with debris-free granulosa cells were classified as morphologically healthy (MH). Granulosa cells were prepared for flow cytometry by fixation in 80% ethanol and staining with propidium iodide (PI) containing RNase. DNA fluorescence intensity was determined by use of the 488-nm line of an argon laser. A subpopulation of granulosa cells with degraded DNA (Ao cells), containing less fluorescence than the Go/G1 peak, was found in the DNA histogram of every follicle. The percentage of Ao cells ranged from 0.02 to 83.6% per follicle. The percentage of Ao cells was inversely related to the percentage of Go/G1 cells (r = -0.9611, p = 0.0001). The percentage of Ao cells (mean +/- SEM) was greater (p = 0.0001) in MA (45.9 +/- 6.3%) than in MH follicles (5.3 +/- 1.6%). Follicular estradiol-17 beta was less in MA than in MH follicles, but androstenedione or progesterone did not differ significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Androstenedione↗

PubMed1994

Steroidogenic cytochrome P450 enzyme messenger ribonucleic acids and follicular fluid steroids in individual follicles during preovulatory maturation in the pig.

Changes in follicular concentrations of steroidogenic cytochrome P450 enzyme mRNAs were determined during preovulatory maturation. RNA was isolated from 59 individual follicles dissected from 18 pigs during altrenogest-synchronized preovulatory follicular maturation: at Day 1 (pre-follicular phase), Day 3 (early follicular phase), Day 5 (mid-follicular phase), and Day 7 (late follicular phase, 24-36 h after the onset of the LH surge). Follicular fluid was aspirated for steroid RIA. RNA was also isolated from pooled granulosa cells, theca tissue, and luteal tissue. RNA was analyzed by Northern and slot-blot procedures using cDNA probes to human aromatase cytochrome P450 (P450arom), porcine 17 alpha-hydroxylase cytochrome P450 (P450(17) alpha), and porcine cholesterol side-chain cleavage cytochrome P450 (P450scc). P450arom mRNA was expressed in both granulosa and theca interna cells but was not detectable in luteal tissue from Day 13 of the estrous cycle. Follicular P450arom mRNA concentration tended to increase between Days 1 and 5 and decreased (p < or = 0.05) by 92% between Days 5 and 7. Follicular fluid estradiol-17 beta concentration increased 17-fold between Days 1 and 5 and then decreased (p < or = 0.05) by 96% between Days 5 and 7. P450(17) alpha mRNA was present in theca interna but was not detected in granulosa cells or luteal tissue. Follicular P450(17) alpha mRNA concentrations did not differ significantly among days, but the content per follicle increased (p < 0.05) between Days 1 and 5 and decreased (p < 0.05) between Days 5 and 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Insulin-like growth factor-binding protein-2 and -3 are correlated with atresia and preovulatory maturation in the porcine ovary.

We compared insulin-like growth factor-binding protein (IGFBP) levels with indicators of follicular maturation and atresia in individual follicles of the porcine ovary. Follicular development was synchronized with the progestin, altrenogest, and progestin withdrawal was used to initiate the growth of an ovulatory cohort of follicles, which is accompanied by atresia of noncohort follicles. Individual follicles were isolated on days 1, 3, 5, and 7 after progestin withdrawal. Atretic follicles were identified by the presence of low hypodiploid levels of DNA in 10% or more of their granulosa cells using flow cytometry. The follicular fluid (FF) level of IGFBP-3 did not differ significantly between healthy and atretic medium-sized (3- to 6-mm) follicles and was not significantly correlated with the percentage of granulosa cells containing hypodiploid levels of DNA (r = 0.181) or with endocrine parameters such as FF concentrations of estradiol or androstenedione. However, among healthy follicles (atretic follicles removed from analyses to better examine follicular maturation), IGFBP-3 increased (P < 0.01) between days 1 and 7 and was positively correlated with follicle diameter (r = 0.514; P < 0.05) and the FF concentration of progesterone (r = 0.556; P < 0.01), indicators of the degree of follicular maturation. FF IGFBP-2 levels were 3-fold greater (P < 0.01) in atretic than in healthy follicles, and IGFBP-2 was correlated with percentage of granulosa cells containing hypodiploid levels of DNA (r = 0.729; P < 0.001). Among healthy follicles, FF IGFBP-2 did not differ significantly among days and was not significantly correlated with follicle diameter. These data suggest that the content of IGFBP-2 is related to the state of follicular health/atresia, whereas IGFBP-3 is related to preovulatory follicular development.

Animals↗

PubMed1993

Changes in follicular estradiol-17 beta, progesterone and inhibin immunoactivity in healthy and atretic follicles during preovulatory maturation in the pig.

Follicular hormones, growth and granulosa cell gonadotropin sensitive adenylate cyclase activity were determined in healthy and atretic follicles during preovulatory maturation in pigs. Ovaries were recovered at slaughter which was 1, 3, 5 or 7 d after the last administration of a progesterone agonist (altrenogest). Plasma FSH decreased (P < .05) by 64% between days 1 and 3 and remained low through day 5. The number of large (> 5 mm) follicles increased from 2.7 on day 1 to 14.8 on day 3 and did not differ significantly among days 3, 5 and 7. The number of small (1-2 mm) and medium (3-5 mm) follicles decreased (P < or = .05) by 82% between days 3 and 5. Follicles first became estrogen-active (EA) (> or = 100 ng of estradiol-17 beta/ml of follicular fluid) on day 3, with 14.3% of medium and 73.8% of large follicles being EA. About 30% of small and 13% of medium follicles were morphologically atretic on days 1 and 3. However, by day 5, the proportion of atretic small and medium follicles had increased (P < or = .05) to 100 and 59%, respectively. Follicular fluid inhibin immunoactivity and estradiol-17 beta were lower (P < or = .05) and progesterone was greater (P < or = .05) in atretic than healthy follicles. Granulosa cells from large follicles produced (P < or = .05) more cAMP than cells from healthy or atretic small/medium follicles. Compared to control or pFSH treatment, pLH increased cAMP production by granulosa cells from large follicles on all days and from small/medium follicles on days 1 and 5; pLH had no effect on granulosa cells from atretic follicles. Compared to control, pFSH increased cAMP production in granulosa cells from healthy small/medium follicles only on day 1; no effect was detected in granulosa cells from large or atretic follicles on any day. We conclude that decreased secretion of FSH increased loss and atresia among non-ovulatory follicles. Atretic follicles were marked by loss of granulosa cell gonadotropin-sensitive adenylate cyclase activity and by low concentrations of estradiol-17 beta.

Animals↗

PubMed1993

Expression of the mRNAs for the insulin-like growth factors and their binding proteins during development of porcine ovarian follicles.

We examined the expression of the mRNAs for the insulin-like growth factors (IGFs) and two of their binding proteins (BPs), IGFBP-2 and IGFBP-3, in individual follicles of the porcine ovary. Follicular development was synchronized with a progestin (altrenogest). Individual follicles were isolated on days 1, 3, 5 and 7 after progestin withdrawal. No IGFBP-3 mRNA was detected. While IGF-II mRNA was easily detected, the levels of expression did not change. IGF-I and IGFBP-2 mRNAs increased and decreased, respectively, with follicle development until day 7 when IGF-I expression declined. Regression analysis of IGF-I and IGFBP-2 mRNA expression was performed to assess the relative strength of correlations with day, diameter and steroid concentrations as covariates. IGFBP-2 mRNA was correlated with both day and diameter (r = -.713 and -.705, respectively, n = 24) and neither estrogen (E2) nor progesterone (P4) contributed to the fit. While IGF-I mRNA expression was correlated to both day (r = .483) and diameter (r = .587), the strongest predictor was E2 concentration (r = .694, n = 27). In conclusion, the expression of IGF-I and IGFBP-2 mRNAs in the ovarian follicle are discordantly regulated during follicular growth and maturation. The observed changes in these parameters should result in increased bioavailable IGF-I. This supports a pivotal autocrine/paracrine role for these factors during follicle growth and development.

Animals↗

PubMed1993

Expression of a bovine growth hormone transgene inhibits pregnant mare's serum gonadotropin-induced follicle maturation in prepuberal gilts.

Prepuberal gilts were injected with PMSG to determine whether expression of a bovine growth hormone (bGH) transgene inhibited preovulatory maturation of ovarian follicles. Seven transgenic (TG) gilts of line 3706, which expresses a mouse metallothionein-bGH transgene, and eight nontransgenic, control (C) gilts (128 to 147 d old) were injected with PMSG, 12.5 IU/kg BW, 72 h before necropsy. Surface ovarian follicles > or = 1 mm in diameter were counted, measured for diameter, and aspirated for fluid. Follicles were classified morphologically as healthy or atretic and those with follicular fluid estradiol-17 beta > or = 100 ng/mL were classified as estrogenactive (EA). The number of follicles per gilt was 64.3 +/- 6.1 (mean +/- SEM) and did not differ significantly between bGH-TG and C gilts. The PMSG treatment induced growth of large (> 5 mm) follicles in both bGH-TG and C gilts. However, compared with C gilts, bGH-TG gilts had fewer (P < .05) large follicles (5.9 +/- 1.5 vs 18.3 +/- 5.4), a lower proportion of EA large follicles (35 +/- 12.5 vs 69 +/- 13.2%), and in large follicles less (P < .05) estradiol-17 beta (86 +/- 17 vs 350 +/- 69 ng/mL) and androstenedione (300 +/- 33 vs 1,283 +/- 221 ng/mL). Follicular fluid progesterone and inhibin did not differ significantly between bGH-TG and C gilts. The incidence of atresia among small and medium follicles did not differ significantly between bGH-TG and C gilts.(ABSTRACT TRUNCATED AT 250 WORDS)

Androstenedione↗

PubMed1993

The role of insulin-like growth factors and epidermal growth factor-related peptides in intraovarian regulation in the pig ovary.

The autocrine and paracrine role of the insulin-like growth factors (IGFs) and epidermal growth factor (EGF)-related peptides in pig ovary are reviewed. For convenience, each of these regulatory systems is divided into several interactive components: regulated expression of the growth factors, growth factor reception at the cell surface and intracellular action of the growth factors. In addition, the concept of regulated bioavailability and targeting of growth factors in the extracellular space is developed as an important control locus and area for future study. With regard to the IGF system, these components include two ligands--IGF-I and -II, both expressed in the porcine ovary--and the possibility of three receptors. IGF-I and the type I IGF receptor appear to be the most important in stimulating ovarian function and amplifying hormone action. In addition, the 'set-point' of the ovarian IGF system may be determined by the activity of several IGF-binding proteins (IGFBPs). At least four of these proteins are expressed in the pig ovary. Studies of their regulation and action in ovarian cells indicate that they can function as antagonists to FSH and the IGFs. However, preliminary evidence suggests a more dynamic model in which these proteins may direct the site and timing of IGF effects. There are fewer data on the EGF system. At least four EGF-related peptides are expressed in pig ovaries, but insufficient information is available to predict their physiological regulation. These peptides are potent mitogens for ovarian cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Changes in concentrations of follicular inhibin alpha and beta A subunit messenger ribonucleic acids and inhibin immunoactivity during preovulatory maturation in the pig.

Ovarian tissues were collected from 5 pigs on each of days 1, 3, 5, and 7 after withdrawal of an orally active progestin to determine changes in follicular inhibin subunit mRNAs during preovulatory maturation. Follicles (N = 146) were aspirated for fluid and homogenized in guanidinium isothiocyanate for RNA isolation. Follicular RNA and inhibin alpha and beta A subunit mRNA standards were dot-blotted, hybridized with [32P]-cDNA probes, and quantified by densitometry. Mean concentrations of alpha mRNA (pg/micrograms of RNA) increased (p < or = 0.05) by 140% as healthy follicles grew from medium (3-5 mm) to large (> 5 mm). Inhibin immunoactivity was greater (p < or = 0.05) in large than medium follicles. In contrast, mean concentrations of inhibin beta A subunit mRNA did not differ between healthy medium and large follicles. However, both alpha mRNA and beta A mRNA increased (p < or = 0.05) linearly as follicular diameter increased from 3 to 5 mm on Day 1 and from 3 to 9 mm on Day 3. On Day 5, alpha mRNA remained elevated, but was not significantly correlated with diameter. In contrast, beta A mRNA decreased linearly (p < 0.05) as diameter increased from 6 to 11 mm on Day 5. The molar ratio alpha mRNA to beta A mRNA was 20:1 in healthy, large follicles on Days 3 and 5. Mean concentration of alpha mRNA in large follicles decreased (p < 0.05) by 72% between Days 5 and 7, while beta A mRNA decreased to non-detectable levels on Day 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1991

Effect of bovine growth hormone gene expression, sex and age on plasma gonadotropins, estrone and testosterone in prepuberal pigs.

Chronic supraphysiological blood levels of growth hormone (GH) may retard sexual maturation in swine. Pigs used in this study included four founder transgenic pigs (two gilts and two boars) expressing a mouse transferrin (TF) promoter fused to a bovine (b) GH structural gene, 13 second- or third- generation transgenic pigs (seven gilts and six boars) expressing a mouse metallothionein (MT) promoter fused to a bGH structural gene and 16 control littermates (eight gilts and eight boars). Blood plasma levels of LH, FSH, estrone and testosterone were measured to determine whether expression of bGH genes altered secretion of hormones between 80 and 180 days of age. Presence of a bGH gene was detected by hybridization of DNA in dot blots of tail biopsies. Expression of a bGH gene was detected by radioimmunoassay of plasma bGH. In four TFbGH founder transgenic pigs bGH ranged from 164 to 1948 ng/ml; in one MTbGH transgenic boar of line 3104 bGH was 1211 ng/ml; and in 12 pigs of line 3706 bGH ranged from 25 to 190 ng/ml. Expression of bGH in transgenic pigs lowered (P = .0192) plasma LH with no significant differences between sexes, had no significant effect on plasma FSH and lowered plasma estrone (P = .0001) and testosterone (P = .0269) in boars (but not gilts). Plasma estrone and testosterone were higher (P = .0001) in boars than in gilts. Plasma FSH was higher (P = .0001) in gilts than boars and decreased (P = .0001) with advancing age in gilts but not in boars.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1991

Changes in the concentration of mRNAs for the inhibin subunits in ovarian follicles after administration of gonadotropins to progestin treated ewes.

RNA was extracted from single or small groups of ovine ovarian follicles after treatment of ewes with FSH and/or LH. The content of mRNA for the alpha-inhibin and beta A-inhibin subunits was analyzed by hybridization with specific cDNA probes. All ewes were treated with progestin vaginal pessaries to suppress spontaneous preovulatory follicle maturation and ewes were given three intramuscular injections of gonadotropins at 8-hr intervals starting 24 hr prior to collection of ovaries. In experiment I, both Schering-FSH and NIDDK-oFSH-17 (oFSH) significantly increased alpha- and beta A-inhibin mRNA per ewe in 2-5 mm follicles and tended to increase alpha- and beta A-inhibin mRNA in large (greater than 5 mm) follicles. In experiment II, oFSH and NIDDK-oLH-25 (oLH) were administered in a 2X2 factorial arrangement. Separate administration of oFSH or oLH increased (P less than .05) the alpha-inhibin mRNA concentration in large follicles. alpha-inhibin mRNA concentration in 4-5 mm follicles was also increased by oFSH but was decreased by oLH. Concomitant treatment with oFSH and oLH did not change alpha-inhibin mRNA concentrations from those measured in oFSH treated ewes. In experiment II, beta A mRNA concentrations followed a pattern similar to that of alpha A mRNA, but the differences were not statistically significant. We conclude that, in the ewe, exogenous FSH increases the concentration of inhibin mRNA in the whole follicle. The ability of exogenous oLH to alter expression of the inhibin subunit genes may depend upon the stage of follicle maturation.

Animals↗

PubMed1990

Changes in plasma follicle-stimulating hormone, luteinizing hormone, estrogen and progesterone during growth of ovulatory follicles in the pig.

This experiment was conducted to determine the changes in secretion of LH, FSH, estrogen and progesterone during follicle maturation. Ovaries were recovered from 11 non-treated (control) gilts, three on day 13, four on day 16, and four on day 19 of the estrous cycle, and from four altrenogest-treated gilts on day 19. Altrenogest, a progesterone agonist, was fed at a dose of 20 mg once daily from days 13 to 18 to block spontaneous follicle maturation. Gilts were bled daily from day 12 until slaughter. For control gilts, the number of follicles/gilt 1-6 mm in diameter decreased (P less than .05) from 93.5 on day 13 to 21.5 on day 19, and the number of large (greater than 6 mm) follicles increased (P less than .05) from 5.3 to 13.2. Altrenogest treatment blocked loss of small follicles and growth of large follicles between days 13 and 19. Plasma progesterone decreased (P less than .001) between days 12 and 16 in both control and altrenogest-treated gilts. Plasma FSH decreased (P less than .05) between days 12 and 16 only in control gilts. Plasma LH was not significantly affected by day or altrenogest treatment. Plasma estrogen increased (P less than .05) between days 15 and 19 only in control gilts. These results indicate that 1) no increased LH secretion was detected in conjunction with emergence of ovulatory follicles, and 2) atresia of nonovulatory follicles was associated with decreased secretion of FSH. Both atresia and decreasing FSH secretion began before estrogen concentration increased in the systemic circulation.

Analysis of Variance↗

PubMed1990

Effects of gonadotropin treatment on ovarian follicle growth and granulosal cell aromatase activity in prepuberal gilts.

This experiment was conducted to compare the ability of USDA porcine FSH-B-1 (pFSH), USDA porcine LH-B-1 (pLH), and pregnant mare's serum gonadotropin (PMSG) to grow large follicles and induce granulosal cell aromatase activity in prepuberal gilts. Twenty-four gilts (164 d old) received one of four treatments by i.m. injection: 1) saline once, n = 8; 2) pFSH (8 micrograms/kg BW, nine times at 8-h intervals), n = 5; 3) pLH (2 micrograms/kg BW, nine times at 8-h intervals), n = 6; or 4) PMSG (15 IU/kg BW, once), n = 5. At slaughter, 72 h after the first injection, the ovaries to saline-treated gilts contained an average of 104 surface antral follicles 1 to 3 mm in diameter. compared to treatment with saline, pFSH increased (P less than .05) the number of follicles 46%, whereas pLH or PMSG decreased (P less than .05) the number by 70 and 84%, respectively. Compared with saline, treatment with PMSG or pLH induced growth of large follicles (7 to 9 mm) (10.8 and 4.8 follicles/gilt, respectively), increased plasma estrogen, increased granulosal cell aromatase activity, and decreased plasma FSH by 51 and 69%; treatment with pFSH had no significant effect on these traits. Results indicate that injected pFSH did not cause growth of large follicles or induce granulosal cell aromatase activity in prepuberal gilts. In contrast, LH initiated growth and increased granulosal cell aromatase activity in a small number of follicles and accelerated atresia among the remaining follicles.

Animals↗

PubMed1988

Ovarian response to injections of charcoal-extracted porcine follicular fluid and porcine follicle-stimulating hormone in gilts fed a progesterone agonist (altrenogest).

This experiment was conducted to compare the negative effects of charcoal-extracted porcine follicular fluid (pFF) and the positive effects of purified porcine follicle-stimulating hormone (pFSH) on growth of follicles and on plasma hormone concentrations. Twenty gilts were fed altrenogest for 18 days (20 mg.day-1.gilt-1) to suppress spontaneous growth of large follicles (greater than 6 mm in diameter). Gilts, assigned at random to receive pFF and pFSH administered in a 2 x 2 factorial arrangement, were injected 9 times at 8-h intervals starting 48 h before the last feeding of altrenogest and ending 8 h before slaughter (24 h after the last feeding of altrenogest). Blood was collected periodically through vena cava catheters. Treatment groups and mean number of medium follicles (3 to 6 mm in diameter)/gilt at necropsy were 1) 20 ml of charcoal-extracted porcine serum i.v. + 4 ml saline i.m., 30.8; 2) 20 ml of pFF i.v. + saline i.m., 0.2; 3) serum i.v. + 8 micrograms of pFSH (USDA-pFSH-B1)/kg BW in saline i.m., 59.0; and 4) pFF i.v. + pFSH in saline i.m., 36.2. Injections of pFF decreased (p less than 0.01) and injections of pFSH increased the number of medium follicles, and the interaction of pFF and pFSH was not significant. Plasma FSH decreased (p less than 0.01) during pFF treatment of saline-injected gilts at a rate of 0.29 ng.ml-1.h-1. During pFSH treatment, plasma FSH increased (p less than 0.05) at statistically identical rates of 0.33 and 0.32 ng.ml-1.h-1 in serum- and pFF-injected gilts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗