Relationship between Plasma Progesterone Concentration and Number of Conceptuses and Their Growth in Superovulated Cattle

Abstract

Abstract. Elevated concentrations of circulating progesterone (P 4 ) in the immediate post-ovulation period are associated with advancement of conceptus elongation in cattle. Superovulated (SOV) cattle have not only elevated plasma P 4 concentrations but also multiple embryos in the uterus because of the formation of multiple corpora lutea. We examined the relationship between plasma P 4 concentration and uterine glucose level in the immediate post-ovulation period and the presence and growth of multiple conceptuses in SOV cattle. SOV cattle were artificially inseminated with frozen-thawed semen at standing estrus (day 0), and the conceptuses were recovered by nonsurgical flushing of the uterus on day 13. In the SOV cattle, there were quadratic relationships between plasma P 4 concentration on days 4, 5 and 7 and conceptus length and between number of conceptuses in the uterus and conceptus length. These results suggest that conceptus growth in SOV cattle is regulated by both systemic P 4 level and number of conceptuses and that there are ranges of plasma P 4 concentrations and numbers of conceptuses in the uterus that are suitable for conceptus growth and development. Plasma P 4 concentrations on days 5 and 7, but not the numbers of conceptuses, were quadratically correlated with uterine glucose levels on day 13 in SOV cattle. In addition, conceptus length was positively correlated with uterine glucose level in SOV cattle. Accordingly, regardless of the number of conceptuses in the uterus, the plasma P 4 concentration was well correlated with the regulation of conceptus growth via changes in uterine glucose levels in SOV cattle. Key words: Cattle, Conceptus growth, Glucose, Progesterone, Superovulation (J. Reprod. Dev. 58: 609-614, 2012) P rogesterone (P 4 ) is crucially involved in the establishment and maintenance of pregnancy in mammals by stimulating and maintaining the endometrial functions necessary for conceptus growth, implantation, placentation and development to term [1,2]. P 4 supplementation has been associated with advancement of conceptus elongation, increases in interferon-tau (IFNT) production, and higher pregnancy rates in cattle [3][4][5][6][7][8][9] and sheep [10][11][12]. In contrast, animals with low concentrations of P 4 in the immediate post-ovulation period show retarded conceptus development [5,13,14], and this reduces IFNT production [5].During early pregnancy, the endometrium synthesizes and secretes histotroph-a complex mixture of enzymes, growth factors, cytokines, lymphokines, hormones, transport proteins, and nutrients-into the uterine lumen [1,15]. Histotrophic nutrition is essential for survival and growth of the conceptus during early pregnancy, as evidenced by the fact that, in ewes, conceptus elongation does not occur in the absence of uterine glands, and consequently, pregnancy is not established [16][17][18]. Moreover, advancement of conceptus growth due to high P 4 concentrations is mediated by the indirect action of P 4 on the uterine endometrium [19]. P 4 affects the par...

Lipid droplets in the ovine uterus during the estrous cycle: Effects of nutrition, arginine, and FSH

“…For example, in humans, gonadotropin treatment resulted in alterations of mRNA expression of receptors for steroids, and other hormones and growth factors in the endometrium, and in steroid serum concentrations [40,41,[77][78][79]. In cows, treatments with gonadotropins resulted in altered oocyte LD accumulation and blastocyst development, expression of genes that regulate metabolic activity of the embryo, serum profile of P4 and PG metabolites, milk E2 concentration, endometrial and embryonic gene expression, and uterine blood flow, secretory functions, morphology and vascular density [43][44][45][80][81][82][83][84]. In mice, some adverse effects of gonadotropin treatments on blastocyst and conceptus gene expression, fetal development and and lower implantation and pregnancy rates have also been demonstrated [85,86].…”

Iron Supplementation in Twin Pregnancy — The Benefit of Doubling the Iron Dose in Iron Deficient Pregnant Women: A Randomized Controlled Trial

“…Lastly, the growing uterus, particularly in the third trimester, may mechanically impede small bowel transit. With higher progesterone and estrogen concentrations in twin pregnancies, a greater suppression of motilin secretion (Gür et al, 2011; Hiraku et al, 2002; Matsuyama et al, 2012) and a larger uterus placing greater pressure on the gastrointestinal tract, the transit time may be prolonged to an even greater extent in twin pregnancies, resulting in greater iron absorption.…”