Concentrations of estrogen (ER) and progesterone (PR) receptors were measured by radioreceptor assay in tumor (n = 319) and normal (n = 166) mammary tissue from 248 bitches. Correlations between ER and PR and between receptor expression in tumor and normal mammary tissue from the same bitches were evaluated. The influence of tumor, clinical, or hormonal variables on receptor expression also was studied. Approximately 80% of tumor and 95% of normal mammary tissue expressed detectable concentrations of ER, PR, or both. Direct correlation was found between ER and PR concentrations in normal and tumor tissues. Median ER concentrations were significantly higher (46 +/- 47 fmol/mg of cytosolic protein vs 27 +/- 24 fmol/mg of cytosolic protein; P = 0.0002) in normal than in tumor tissue. On the other hand, PR concentrations were significantly higher (57 +/- 52 fmol/mg vs 77 +/- 99 fmol/mg; P = 0.03) in tumors (especially benign tumors) than in normal tissue. Poorly differentiated malignant tumors expressed lower concentrations of receptors than did benign or well differentiated malignant tumors. The ER and PR concentrations decreased with increasing size of the lesion. Hormonal status of the bitch significantly (P < 0.05) influenced receptor expression in normal tissue: bitches in the luteal phase of the estrous cycle had higher concentrations of ER (69 +/- 62 fmol/mg) than did ovariectomized bitches (24 +/- 19 fmol/mg) or bitches in anestrus (38 +/- 45 fmol/ mg) or the follicular phase (13 +/- 7 fmol/mg). For PR, higher concentrations were observed in normal tissue during anestrus than during pseudopregnancy or in bitches treated with medroxyprogesterone acetate. Similar, but nonsignificant, variations were seen in tumor tissue except in medroxyprogesterone acetate-treated bitches in which PR concentrations were high in tumors and low in normal tissue from the same bitches.

During the breeding season, the effect of constant administration of an agonist analog of gonadotropin-releasing hormone (GnRH; goserelin acetate) on reproductive activity of mares was determined. Twenty-four mares undergoing estrous cycles were allocated at random to 6 groups (n = 4/group) and, on May 29 (day 0), received no treatment (group 1, controls), 120 micrograms (group 2), 360 micrograms (group 3), 600 micrograms (group 4), or 1,200 micrograms (group 5) of GnRH agonist/d for 28 days via a depot implanted subcutaneously. The final group of mares (group 6) was treated with 120 miocrograms of GnRH agonist/d for 84 days (3 occasions at 28-day intervals). During a pretreatment period (April 19 to May 29) and for 90 days after initiation of GnRH agonist treatment, follicular development and ovulation were monitored by transrectal ultrasonography of the reproductive tract at 2- to 3-day intervals. On each occasion a blood sample was collected for determination of luteinizing hormone (LH) and progesterone. Estrous behavior was monitored by teasing of mares with a stallion. Initiation of agonist treatment was random, relative to the stage of the estrous cycle, and all mares ovulated within 11 days before or after implantation. in 3 of 4 nontreated control mares, estrous cycles were observed throughout the study, with interovulatory intervals ranging from 18 to 26 days. In the remaining mare, concentration of progesterone was high after asynchronous double ovulation during the pretreatment period, suggestive of persistent corpus luteum. In group-2 mares, ovulation occurred in all mares 7 days before and 2 days after initiation of treatment; however, the next anticipated ovulation was delayed in 3 of 4 mares (interovulatory interval, 33 to 70 days). Estrous cycles were not disrupted in the remaining mare. At higher doses (groups 3-5), 1 mare each from groups 3 and 5 ovulated between days 0 and 2 of treatment initiation.

Serum concentration of ampicillin, a semisynthetic penicillin, was measured in mares at various time intervals up to 24 hours after intrauterine infusion of 3 g of ampicillin. Blood samples were drawn immediately before infusion and at l-, 4-, 10- and 24-hour intervals after infusion. At postinfusion hour 24, two endometrial biopsy specimens were obtained to measure endometrial concentrations of ampicillin. Blood was drawn twice as part of the 24-hour postinfusion sample collection, once before removal of the biopsy specimens and again 5 minutes after removal of the biopsy specimens. After drug infusion, more diestrous mares had detectable serum ampicillin concentration than did estrous mares for all samples, except the 24-hour prebiopsy sample. None of the 24-hour prebiopsy serum samples had detectable ampicillin concentration, but ampicillin was detected in the serum of 4 of 5 diestrous mares after endometrial biopsy. Endometrial concentrations of ampicillin were detectable at postinfusion hour 24 in estrous and diestrous mares, but were not different. All 24-hour biopsy specimens had ampicillin concentrations greater than the ampicillin minimal inhibitory concentration.

Plasma luteinizing hormone and progesterone concentrations, time to onset of estrus, and pregnancy rates were determined in nonlactating anestrous does given 1 of 4 treatments: subcutaneous ear implants containing 3 mg of norgestomet for 9 days (NOR; n = 6); subcutaneous administration, using osmotic minipumps, of 250 ng of gonadotropin-releasing hormone (GnRH)/h for 48 hours (GnRH; n = 6); 3 mg of NOR for 9 days, followed immediately by 250 ng of GnRH/h for 48 hours (NOR + GnRH; n = 6); or no treatment (control; n = 6). During the 72-hour period after removal of NOR or insertion of GnRH pumps, 6 of 6, 0 of 6, 6 of 6, and 3 of 6 does were observed in estrus at a mean (+/- SE) of 49 (+/- 3.0), 0(+/- 0), 32 (+/- 2.0), and 35 (+/- 13.8) hours in groups NOR, GnRH, NOR + GnRH, and control, respectively. Time from end of treatment to peak concentrations of luteinizing hormone were 56 +/-4.0, 28 +/- 4.7, 34 +/- 4.3, and 41 +/- 9.7 hours (mean +/- SE) for NOR, GnRH, Nor +/- GnRH, and control, respectively. Peak concentrations of luteinizing hormone were significantly greater and occurred significantly later in does given NOR. Progesterone concentrations in does that became pregnant increased to concentrations greater than or equal to 1.0 ng/ml 3 to 5 days after breeding and remained high. Functional corpora lutea (CL) was found in 6 does that did not become pregnant, 1 CL was associated with pseudopregnancy and 1 CL was associated with ovulation prior to placement of the GnRH pumps. Functional CL failed to form in 10 of the 12 does in groups GnRH and control. Does had either continual low concentrations of progesterone (3 does) or short-term increases in concentrations of progesterone (7 does). Conception rates for does in groups NOR, GnRH, NOR + GnRH, and control were 83%, 0%, 50% and 0%, respectively. Four does given GnRH and 3 control does were observed in estrus and were bred during the subsequent 2-week period. All of these does, except 1 control became pregnant subsequent to these breedings. The treatments NOR and NOR + GnRH were effective in inducing a synchronized estrus in dairy goats. However, the use of bucks to detect estrus may have introduced the buck effect and enhanced the performance of NOR alone, which has not been this effective in other studies with small ruminants.

A cadela apresenta particularidades reprodutivas que a diferencia de outras espécies. Diversos experimentos têm sido realizados visando estabelecer protocolos eficientes para a maturação, entretanto os resultados mostram-se insatisfatórios. Nesse aspecto, a fase reprodutiva da fêmea doadora deve ser considerada, já que pode ser um fator de variabilidade dos achados ate então presenciados nessa espécie. O objetivo deste estudo foi avaliar a influencia das fases do ciclo estral (anestro e diestro) na maturação in vitro (MIV) de cadelas. Os ovários foram transportados em solução de cloreto de sódio 0,9% e seccionados em solução salina fosfato tamponado (PBS) e os complexos cumulus-oócito (COCs) selecionados em meio de cultura de tecidos (TCM) 199 suplementado com HEPES. Foram obtidos 469 oócitos grau 1 de cadelas em anestro e diestro. Esses oócitos selecionados foram transferidos para o meio de maturação por um período de 72 horas, sendo posteriormente submetidos a solução de hialuronidase e corados com HOESCHT 33342 para avaliação da configuração nuclear. A comparação das fases de anestro e diestro não revelou diferença (p > 0,05) entre os estágios de maturação nuclear. Dessa maneira, a fase do ciclo estral não influenciou na maturação in vitro de oócitos caninos, incrementando os índices de M-II nesta espécie.

Different segments of oviduct (infundibulum, ampulla, isthmus and utero tubaljunction)of six buffaloes each during follicular and luteal phases of estrous cycle were studied. The samples were collected in 10% NBF processed for paraffin sectioning were stained with hematoxylin and eosin, Masson's trichrome, PetiodicAcid Schiff, alcian blue and PASalcian blue. The mucosa was found thrown into longitudinal folds having primary, secondary and tertiary branches. Branching was more pronounced in infundibulum and ampulla as well as during the follicular phase as compared to luteal phase. The different segments were lined with columnarto pseudostratifiedcolumnarepithelium.The cellswere ciliatedand non ciliated type. In follicular phase, the epithelium showed strong PASreaction which was con~entrated in the supranuclear zone while during the luteal phase the reaction was moderate. The reaction was granular in nature. The epithelium was also strongly positive for alcian blue and PASalcian blue during follicularphase. Thepropria submucosa, tunica muscularis and tunica serosa showed weak to mild reaction for PASand alcian blue.