Cécile Bienboire-Frosini¹, Camille Chabaud¹, Rosaria Esposito², Morgan Mathieu^2
1IRSEA, Apt, France
²Enzo Life Sciences, Lausen, Switzerland

Featured Product: Progesterone ELISA kit, Testosterone ELISA kit

HIGHLIGHTS

• Enzo’s Progesterone and Testosterone ELISA Kits were tested with ewe and ram plasma, respectively.
• Precision, accuracy, parallelism and linearity under dilution were evaluated.
• These kits are able to recognize and bind in a specific manner the hormones present in the samples, without significant interference caused by the biological matrix.

INTRODUCTION

Progesterone is the major female sex hormone. This steroid is responsible for reproductive activities. It is secreted in large amounts by the corpus luteum and in small quantities directly by the adrenal glands (Aufrere & Benson, 1976; Bardin et al., 1983; Greenspan & Forsham, 1986). Most of the progesterone circulating in the blood is bound to serum proteins such as albumin, while a small portion roams free (Dunn et al., 1981). Testosterone is the main androgen secreted by Leydig cells in testes and effects both primary and secondary sexual development such as muscle mass and sex drive (Imperato-McGinley et al., 1974; Wilson et al., 1981). It circulates in plasma predominately bound to proteins such as albumin or sex hormone-binding globulin (SHBG) (Griffen & Wilson, 1992).

In sheep, reproduction is seasonal and breeding season ends as daylight increases. An increase in frequency of LH pulses and consequently ovulation can, however, be triggered by introducing a male into a flock of ewes in anoestrous. This phenomenon, caused by male pheromones, is called “ram effect” and it is used to manipulate sheep reproduction during the anoestrous season (Rosa et al., 2002; Delgadillo et al., 2009; Fabre-Nys et al., 2016). The ram effect is studied by the researchers at IRSEA (Pageat et al., 2014; Asproni et al., 2017). In this context, rams’ secretions are used to stimulate pre-ovulatory LH peaks in ewes. The levels of progesterone in ewes’ plasma need to be measured to evaluate the anoestrous state. In parallel, testosterone levels in ram plasma can be evaluated in order to investigate its role in pheromones emission.

The aim of the study reported here is to validate Enzo's Progesterone and Testosterone ELISA kits for the quantitative measurement of these hormones in sheep plasma. Enzo has already established several performance criteria, such as the sensitivity, the linearity, the precision, the cross-reactivity and the accuracy. However, because of the different biological matrix (sheep plasma), it is necessary to perform a partial validation to test the intra-assay precision (repeatability), the accuracy as well as the linearity and parallelism (Andreasson et al., 2015).