Concentration of intrafollicular estradiol and progesterone in mares treated with hCG and its relation to plasma progesterone profile after follicular aspiration

• Grant number: 11/22953-4
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): January 01, 2012
• Effective date (End): July 31, 2012
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Cezinande de Meira
• Grantee: Aline Alves Gruenwaldt Cunha
• Home Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The corpus luteum is a temporary gland formed from ovulation of no importance in controlling the estrous cycle and in the maintenance of pregnancy due to progesterone production. To have your training, and luteinized follicular cells undergo inversion estereidogênse, which involves a series of complex factors. During follicular maturation the follicle acquires characteristics of responding to the factors luteinizing follicular cells, and the dosage of intrafollicular concentrations of estradiol and progesterone, were strong indications of follicular maturation. The application of hCG promotes the expansion of the follicular cells and increased estereidogênese in growing follicles. The objectives of this study aims to assess the concentration of estradiol and progesterone in follicular fluid of follicles e 25 and e 30mm, whether or not under the influence of exogenous hCG and correlate intrafollicular concentrations of estradiol and progesterone are two categories of follicular (e 25 and e 30 mm) with subsequent plasma progesterone. Will be used for follicular fluid samples follicles e 25 mm (n = 14) and e 30 mm (n = 14) aspirated from mares in good body condition, aged between four and 15 years and cycling regularly. The follicular fluid samples will be divided into four groups according to prior treatment: Group-25hCG (n = 7) and Group-30hCG (n = 7), these two groups will receive the mares intramuscularly 2.500UI hCG respectively, when the follicles reach a diameter e 25 or e 30 mm. For 25Salina groups (n = 7) and 30Salina (n = 7) to be used as a control, the mares will also receive intramuscularly, saline volume equal to that of hCG at the time of detection of follicles e 25 (Group-25Salina ) or e 30 mm (Group-30Salina). Twenty four hours after treatment with hCG or saline, the follicles are aspirated and follicular fluid samples in duplicate will be stored at -20 ° C for later determination of estrogen and progesterone. Blood samples will be obtained in heparinized tubes by puncture of the jugular vein every 24 hours immediately prior to treatment with hCG or saline (D-1, D0 = follicle aspiration), continuing up until 15 days after follicle aspiration . Blood samples are centrifuged and the plasma stored as described for follicular fluid for subsequent measurement of the concentration of progesterone. The concentration of serum progesterone, estradiol and progesterone in follicular fluid are determined by radioimmunoassay. The follicular fluid samples are diluted to achieve concentrations that meets the standard curve assay, specific for each hormone. The accuracy of intra-and inter-assay will be determined by the repetition of the control samples in each assay. For statistical analysis, variance analysis will be performed in a completely randomized design (P <0.05) to check the maximum concentration of P4. For serum progesterone concentration (ng / mL) is carried out repeated-measures analysis (P <0.05). For comparison of means by Tukey test (P <0.05) will be used. Still be performed correlations between intrafollicular E2 and P4, P4 maximum concentration and number of days it took to reach this concentration.