scholarly journals Impact of maternal nutrition during pregnancy on pituitary gonadotrophin gene expression and ovarian development in growth-restricted and normally grown late gestation sheep fetuses

Reproduction ◽  
2002 ◽  
pp. 769-777 ◽  
Author(s):  
P Da Silva ◽  
RP Aitken ◽  
SM Rhind ◽  
PA Racey ◽  
JM Wallace
Keyword(s):  
Gene Expression ◽  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Nutrient Intake ◽  
Ovarian Development ◽  
Maternal Nutrition ◽  
Follicular Development ◽  
Late Gestation ◽  
Complete Diet ◽  
High Nutrient

The influence of maternal nutrition during pregnancy on anterior pituitary gonadotrophin gene expression and ovarian development in sheep fetuses during late gestation was investigated. Embryos recovered from superovulated adult ewes that had been inseminated by a single sire were transferred, singly, into the uteri of adolescent recipients. After embryo transfer, adolescent ewes were offered a high or moderate amount of a complete diet. Pregnancies were terminated at day 131 +/- 0.6 of gestation and the fetal brain, anterior pituitary gland and gonads were collected. Gonadotrophin gene expression (LHbeta and FSHbeta subunits) in the fetal pituitary gland was examined using in situ hybridization. Ovarian follicular development was quantified in haematoxylin- and eosin-stained ovarian sections embedded in paraffin wax. Six dams that were offered a high nutrient intake carried normal-sized fetuses (weight within +/- 2 SD of mean weight for control fetuses from dams fed a moderate level of complete diet) and 13 dams carried growth-restricted fetuses (weight +/- 2 SD of mean weight for control fetuses from dams fed a moderate level of complete diet). Mean placental masses in these groups were 354 +/- 24.5 and 230 +/- 21.1 g, respectively, compared with 442 +/- 54.3 g in the dams that were offered a moderate nutrient intake (n = 6). Growth-restricted fetuses from dams offered a high nutrient intake showed higher pituitary LHbeta mRNA expression (P < 0.05) than normal-sized fetuses from dams offered a moderate nutrient intake (252 +/- 21.6 and 172 +/- 23.6 nCi g(-1), respectively). FSHbeta mRNA expression was not influenced by growth status. Fewer follicles (primarily in the resting pool) were observed in the ovaries of both growth-restricted (P < 0.002) and normal-sized fetuses from dams offered a high nutrient intake (P < 0.01) compared with normal-sized fetuses from dams offered a moderate nutrient intake. Irrespective of nutritional treatment, the total number of follicles was positively associated with placental mass (P < 0.01). Thus, a high maternal nutrient intake during adolescent pregnancy had a negative influence on ovarian follicular development in fetuses as determined during late gestation.

Effects of corticotropin-releasing hormone and its antagonist on the gene expression of gonadotrophin-releasing hormone (GnRH) and GnRH receptor in the hypothalamus and anterior pituitary gland of follicular phase ewes

2011 ◽  
Vol 23 (6) ◽  
pp. 780 ◽  
Author(s):  
Magdalena Ciechanowska ◽  
Magdalena Łapot ◽  
Tadeusz Malewski ◽  
Krystyna Mateusiak ◽  
Tomasz Misztal ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Follicular Phase ◽  
Gnrh Receptor ◽  
Corticotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone ◽  
Lh Secretion ◽  
Crh Receptors

There is no information in the literature regarding the effect of corticotropin-releasing hormone (CRH) on genes encoding gonadotrophin-releasing hormone (GnRH) and the GnRH receptor (GnRHR) in the hypothalamus or on GnRHR gene expression in the pituitary gland in vivo. Thus, the aim of the present study was to investigate, in follicular phase ewes, the effects of prolonged, intermittent infusion of small doses of CRH or its antagonist (α-helical CRH 9-41; CRH-A) into the third cerebral ventricle on GnRH mRNA and GnRHR mRNA levels in the hypothalamo–pituitary unit and on LH secretion. Stimulation or inhibition of CRH receptors significantly decreased or increased GnRH gene expression in the hypothalamus, respectively, and led to different responses in GnRHR gene expression in discrete hypothalamic areas. For example, CRH increased GnRHR gene expression in the preoptic area, but decreased it in the hypothalamus/stalk median eminence and in the anterior pituitary gland. In addition, CRH decreased LH secretion. Blockade of CRH receptors had the opposite effect on GnRHR gene expression. The results suggest that activation of CRH receptors in the hypothalamus of follicular phase ewes can modulate the biosynthesis and release of GnRH through complex changes in the expression of GnRH and GnRHR genes in the hypothalamo–anterior pituitary unit.

scholarly journals Effect of maternal nutrition and days of gestation on pituitary gland and gonadal gene expression in cattle

2016 ◽  
Vol 99 (4) ◽  
pp. 3056-3071 ◽  
Author(s):  
M.M.D.C.A. Weller ◽  
M.R.S. Fortes ◽  
M.I. Marcondes ◽  
P.P. Rotta ◽  
T.R.S. Gionbeli ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pituitary Gland ◽  
Maternal Nutrition

scholarly journals Aspects of Ovarian Function in a Line of Sheep with a Novel X-Linked Maternally-Imprinted Gene that is Associated with an Increased Ovulation Rate

2021 ◽  
Author(s):  
◽  
Elisabeth Sheinach Feary
Keyword(s):  
Gene Expression ◽  
Pituitary Gland ◽  
Ovarian Function ◽  
Follicular Development ◽  
Cell Types ◽  
Ovulation Rate ◽  
Chromosome 2 ◽  
Ovarian Follicular Development ◽  
Er Alpha ◽  
Large Ovary

<p>Fecundity is a term that refers to the number of offspring produced per female. It combines fertility (i.e. ability to produce offspring) and prolificacy (i.e. number of offspring). Ovulation rate i.e. the number of mature eggs released from the ovaries during one reproductive cycle in sheep, as with other mammals, is controlled by an exchange of hormonal signals between the pituitary gland and the ovary. Genetic mutations affecting ovulation are commonly referred to as the fecundity genes (Fec). The most obvious outcome is the number of offspring produced. There is already evidence of a number of major genes affecting the ovulation rate in sheep, specifically the Booroola, Inverdale, Hanna and more recently the Woodlands gene. The sheep carrying the Woodlands gene arose because the mutation was first recognised on a farm in Woodlands, Southland, New Zealand. Woodlands have a novel, X-linked maternally-imprinted, fecundity trait referred to as FecX2w, where Fec = fecundity, X = X chromosome, 2= 2nd mutation identified on X and W= Woodlands. The studies in this thesis investigated ovarian follicular development in both 4-week old Woodland carrier (W+) and non-carrier (++) lambs and adult ewes and evaluated some aspects of the endocrine interactions between the ovary and pituitary gland. The purpose was to identify potential physiological effects of the FecX2w gene on ovarian function. A confounding issue during these studies was the discovery that a large ovary phenotype (LOP) which was present in many of the W+ but not ++ lambs at 4 weeks of age was in fact a coincidence and not linked to the FecX2w mutation. The key findings from the studies of lambs and/or ewes that were carriers (W+) or non-carriers (++) of the FecX2w gene were: 1. No genotype differences were present either in the numbers of primordial (i.e. Type 1/1a follicles) or developing preantral (i.e. Types 2-4 follicles); 2. Significant genotype differences were present in the numbers of small antral (Type 5) follicles (W+>++; p<0.05); 3. An earlier onset of antral follicular development in W+ vs. ++ ewes with irregularities in morphology between the basement membrane and stroma in the former; 4. No genotype differences in the onset of gene expression during follicular development or in the cell-types expressing GDF9, BMP15, alpha inhibin, beta A inhibin and beta B inhibin, FSHR, ER alpha, or ER beta; 5. No genotype differences in the levels of GDF9 or BMP15 gene expression in oocytes throughout follicular growth; 6. No genotype difference in the diameters that follicles reached in W+ vs. ++ ewes; 7. Some lambs at 4-weeks of age had unusually large ovaries with an exceptional level of antral follicular development that is reminiscent of a polycystic ovarian condition. The underlying cause of this condition is unknown. In conclusion, the physiological characteristics of ovarian follicular development in ewes with the FecX2w gene is different from that in ewes with the Booroola, Inverdale, Hanna or other recently identified mutations.</p>

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