Unformatted text preview: The displacement of a known amount of ("hot") tracer-labeled hormone by controlled addition of purified ("cold") hormone, after separation and counting yields a standard curve Unknown quantities of hormone in samples are then determined by reading (*) the standard curve Y=log(B/B0) Validations: Sensitivity or limit of detection (minimum antigen (Ag), plus an indicator with v. high specific activity (readily detected), AB-Ag affinity) Specificity (AB specifically binds the hormone of interest, not other things) Accuracy (how accurate is the actual value obtained as compared to the real value using pure standards) Precision (reliability) intra-assay CV (10 within assay determinations) inter-assay CV (10 assays worth of standard low, medium and high pools) Q. imprecise=really bad | Precise, even inaccurate = okay, because you can compare the changes Standard curve Parallelism (commonly used to test new antibody batches) Note: Antibody binding assays (RIA's, Receptor binding assays, EIA's etc.) only tell the amount of "immuoreactive" hormone or receptor present since they only identify the presence of the antibody identifying region, not necessarily the amount of active hormone or receptor present SITES WHERE HORMONE REGULATION CAN OCCUR 1. Synthesis: Transcription, mRNA, protein synthesis, post-translational,* (e. g. inactive prohormone synthesis & enzymatic change to active hormone) 2. Control of release (decrease in receptor numbers that inhibit release) 3. Blood binding protein levels (theoretical) * 4. End-organ receptor numbers * 5. Post-receptor regulation (e.g. T3 from T4; Dihydrotestosterone [DHT] in sex accessory tissues or Estradiol in brain from testosterone) 6. Clearance and metabolism to inactivity; this typically involves single or multiple steps to make metabolites which are no longer active intermediates) Estrus vs. menstrual cycles: Really, behavioral estrus vs. no behavior change ...the designation of these two cycle types has to do with what is the most outward sign, so ID of the cycle stage is possible For example, the use of "behavioral estrus" started from animal husbandry where breeding at estrus was "behavioral estrus" practiced to improve genetic stock, and utilize labor better it is generally accepted that higher primates hide ovulation as a social cohesive force, so menstruation becomes the Reference e. g. estimating conception dates Decidualization is the build-up of the endometrium to be able to allow the fertilized zygote to embed deeply (interstitial implantation) into the endometrium High Estradiol in the follicular phase causes endometrial proliferation -proliferative phase -proliferative Ovulation leads to endometrial secretion under progesterone influence via the corpus luteum (CL) during the secretory phase Non-rescue of the CL (rescue is via human chorionic gonadotropin (hCG)) leads to menstruation Non-rescue (h 2 pregnancy maintenance plans-involving CL rescue: 1. CL maintains pregnancy until the placenta takes over - producing progesterone (P4) until the placenta does so (switch: ~ 36 days gestation in humans and great apes, earlier in other old world primates) 2. CL maintains pregnancy until term- sometimes (experimentally) even without a uterus (e. g. ferrets), and regresses 12 hours prior to delivery (ferrets: normal gestation is 39 d) a. Autonomous CL (ferret) b. Feedback CL (dog and others) Luteolysis = CL atrophy starts next cycle Most commonly-endometrial Prostaglandin's cause luteolysis to start a new cycle PG's cause pregnancy termination at any stage of gestation (CL or placental) ...
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- Spring '08
- Physiology, behavioral estrus, plans-involving CL rescue, Receptor binding assays, active hormone