ELISA for the measurement of serum and urinary chorionic gonadotropin concentrations in the laboratory macaque

Abstract

A rapid, sensitive, enzyme‐linked immunosorbant assay (ELISA) for the measurement of chorionic gonadotropin (CG) in serum and urine samples of laboratory macaques is reported. The ligand (CG) is captured by a readily available, widely used, and well‐characterized monoclonal anti‐body (Mab, 518B7) generated against the β subunit of bovine luteinizing hormone (LH). This Mab, while specific for LH, shows very little species specificity, and has been shown to detect LH and CG by radioimmunoassay (RIA) in both human and non‐human primates. A polyclonal antiserum raised in rabbits against human chorionic gonadotropin (hCG) is conjugated to horseradish peroxidase, and is used as the second anti‐body signal. This anti‐hCG antiserum cross reacts with CG secreted by both the human (hCG) and macaque (mCG). The ELISA utilizes hCG as the standard, and results are based on the relative concentrations of mCG in serum and urine. Total assay time is less than 5 hours. Range of the standard curve is 0.002 to 0.5 ng hCG/well, and the least detectable concentration of hCG is 0.0023 ± 0.0007 ng/well. Pregnancy was detected in early pregnant macaques (M. fascicularis) on 9 (N = 1/16), 10 (N = 1/16), 11 (N = 1/16), 12 (N = 6/16), 13 (N = 1/16), 14 (N = 4/16), and 15 (N = 2/16) days following the pre‐ovulatory urinary estrone conjugate peak. The detection of pregnancy by urinary mCG occurred approximately 24 to 72 hours after its detection in serum. Am. J. Primatol. 41:307–322, 1997. © 1997 Wiley‐Liss, Inc.

Studies on Reproductive Endocrinology in Non-human Primates: Application of Non-invasive Methods

“…The measurement of CG, a marker of trophoblast invasion and implantation, has been an important tool for the detection of early pregnancy and the u n d e r s t a n d i n g o f t h e e n d o c r i n e c h a n g e s surrounding implantation in many primate species [17,24]. While a number of methods are available for CG determination, each method has several practical disadvantages when routinely applied.…”

“…The mCG NELISA is a modification of ELISA [17] and the major change was a change in the solid matrix used. The end point of the assay is a color change, which is visible to the unaided eye.…”

Endocrine Biomarkers of Early Fetal Loss in Cynomolgus Macaques (Macaca fascicularis) Following Exposure to Dioxin1

“…Animals were bred on cycle Days 10 and 12, and this breeding interval was verified to encompass the periovulatory E 1 C peak. Pregnancy was confirmed on GD 12 by the measurement of Ͼ 1 ng/ml serum CG [9] and by trans-abdominal ultrasound [10] (Ultramark 9; Advanced Technology Laboratories, Inc., Bothell, WA). There were no false positives or negatives using CG measurements and sonography [10].…”

Ovarian Choriocarcinoma in a Rhesus Monkey Associated with Elevated Serum Chorionic Gonadotropin Levels

“…12 Blood remaining from samples drawn at the beginning of the study was tested for monkey chorionic gonadotropin (mCG) using an enzyme linked immunosorbent assay (ELISA), as previously described. 9 In women with choriocarcinoma, chorionic gonadotropin levels are often elevated. 12 The mCG level in this monkey was 1.90 ng/ml.…”