These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Estrogen concentrations in bovine and porcine tissues.
    Author: Hendricks DM.
    Journal: J Toxicol Environ Health; 1976 Mar; 1(4):617-39. PubMed ID: 1263281.
    Abstract:
    Using an estrogen antiserum that measures biologically active estrogen (estradiol-17beta + estrone), a series of studies have been completed to describe the normal plasma levels of estrogen in cows and sows during various stages of reproduction. The levels are lower in the nonpregnant cow (less than 25 pg/ml) than in most species. Only during late pregnancy are the levels easily assayed. The levels in the nonpregnant sow are 2-3 times greater than in the cow. In both species there is a preovulatory peak of estrogen that is responsible for estrus. Plasma estrogen concentrations were also determined after induction of multiple ovulations by exogenous gonadotropin (PMSG) in the cow and sow and after treatment of cows with either a progestin (MGA) or a prostaglandin (PGF2alpha). (These two drugs have been used to synchronize estrus in the cow.) Estrogen levels rise greatly after treatment with PMSG but show little effect from MGA or PGF2alpha. Data are also presented on the validation of an assay for E2beta and E1 in beef tissue. Less than 20 pg of E2beta and E1 was measured per gram bovine muscle tissue. Considerable effort must be expended to apply radioimmunoassay to the assay of estrogens in tissues. A series of studies conducted to determine normal plasma levels of estrogen during various stages of reproduction in cows and sows is reported. The studies employed an estrogen antiserum to measure plasma levels of estradiol-17beta and estrone. Estrogen levels in the nonpregnant cow were less than 25 pg/ml, which is lower than in most species. During late pregnancy, however, estrogen levels were easily assayable. Nonpregnant sows showed estrogen levels 2-3 times greater than observed in nonpregnant cows. A preovulatory peak of estrogen, which is responsible for promoting estrus, was observed in both species. Estrogen levels markedly increased after the induction of multiple ovulation by administration of pregnant mare's serum gonadotropin in both species. However, the administration of either melengestrol acetate or prostaglandin F2alpha, each of which is used to synchronize estrus in the cow, had little effect on estrogen levels in the cow. The development of specific estrogen radioimmunoassays for muscle, liver, and kidney tissues is discussed.
    [Abstract] [Full Text] [Related] [New Search]